tiff: Check that there is no aliasing in pixel format selection
[ffmpeg.git] / libavcodec / mpeg4videodec.c
index 17b1190..0966e07 100644 (file)
  */
 
 #include "error_resilience.h"
+#include "idctdsp.h"
+#include "internal.h"
+#include "mpegutils.h"
 #include "mpegvideo.h"
 #include "mpeg4video.h"
 #include "h263.h"
 #include "thread.h"
+#include "xvididct.h"
 
-// The defines below define the number of bits that are read at once for
-// reading vlc values. Changing these may improve speed and data cache needs
-// be aware though that decreasing them may need the number of stages that is
-// passed to get_vlc* to be increased.
+/* The defines below define the number of bits that are read at once for
+ * reading vlc values. Changing these may improve speed and data cache needs
+ * be aware though that decreasing them may need the number of stages that is
+ * passed to get_vlc* to be increased. */
 #define SPRITE_TRAJ_VLC_BITS 6
 #define DC_VLC_BITS 9
 #define MB_TYPE_B_VLC_BITS 4
 
-
 static VLC dc_lum, dc_chrom;
 static VLC sprite_trajectory;
 static VLC mb_type_b_vlc;
 
-static const int mb_type_b_map[4]= {
+static const int mb_type_b_map[4] = {
     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
-    MB_TYPE_L0L1 | MB_TYPE_16x16,
-    MB_TYPE_L1 | MB_TYPE_16x16,
-    MB_TYPE_L0 | MB_TYPE_16x16,
+    MB_TYPE_L0L1    | MB_TYPE_16x16,
+    MB_TYPE_L1      | MB_TYPE_16x16,
+    MB_TYPE_L0      | MB_TYPE_16x16,
 };
 
 /**
@@ -51,391 +54,421 @@ static const int mb_type_b_map[4]= {
  * @param n block index (0-3 are luma, 4-5 are chroma)
  * @param dir the ac prediction direction
  */
-void ff_mpeg4_pred_ac(MpegEncContext * s, int16_t *block, int n,
-                      int dir)
+void ff_mpeg4_pred_ac(MpegEncContext *s, int16_t *block, int n, int dir)
 {
     int i;
     int16_t *ac_val, *ac_val1;
-    int8_t * const qscale_table = s->current_picture.f.qscale_table;
+    int8_t *const qscale_table = s->current_picture.qscale_table;
 
     /* find prediction */
-    ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
+    ac_val  = s->ac_val[0][0] + s->block_index[n] * 16;
     ac_val1 = ac_val;
     if (s->ac_pred) {
         if (dir == 0) {
-            const int xy= s->mb_x-1 + s->mb_y*s->mb_stride;
+            const int xy = s->mb_x - 1 + s->mb_y * s->mb_stride;
             /* left prediction */
             ac_val -= 16;
 
-            if(s->mb_x==0 || s->qscale == qscale_table[xy] || n==1 || n==3){
+            if (s->mb_x == 0 || s->qscale == qscale_table[xy] ||
+                n == 1 || n == 3) {
                 /* same qscale */
-                for(i=1;i<8;i++) {
-                    block[s->dsp.idct_permutation[i<<3]] += ac_val[i];
-                }
-            }else{
+                for (i = 1; i < 8; i++)
+                    block[s->idsp.idct_permutation[i << 3]] += ac_val[i];
+            } else {
                 /* different qscale, we must rescale */
-                for(i=1;i<8;i++) {
-                    block[s->dsp.idct_permutation[i<<3]] += ROUNDED_DIV(ac_val[i]*qscale_table[xy], s->qscale);
-                }
+                for (i = 1; i < 8; i++)
+                    block[s->idsp.idct_permutation[i << 3]] += ROUNDED_DIV(ac_val[i] * qscale_table[xy], s->qscale);
             }
         } else {
-            const int xy= s->mb_x + s->mb_y*s->mb_stride - s->mb_stride;
+            const int xy = s->mb_x + s->mb_y * s->mb_stride - s->mb_stride;
             /* top prediction */
             ac_val -= 16 * s->block_wrap[n];
 
-            if(s->mb_y==0 || s->qscale == qscale_table[xy] || n==2 || n==3){
+            if (s->mb_y == 0 || s->qscale == qscale_table[xy] ||
+                n == 2 || n == 3) {
                 /* same qscale */
-                for(i=1;i<8;i++) {
-                    block[s->dsp.idct_permutation[i]] += ac_val[i + 8];
-                }
-            }else{
+                for (i = 1; i < 8; i++)
+                    block[s->idsp.idct_permutation[i]] += ac_val[i + 8];
+            } else {
                 /* different qscale, we must rescale */
-                for(i=1;i<8;i++) {
-                    block[s->dsp.idct_permutation[i]] += ROUNDED_DIV(ac_val[i + 8]*qscale_table[xy], s->qscale);
-                }
+                for (i = 1; i < 8; i++)
+                    block[s->idsp.idct_permutation[i]] += ROUNDED_DIV(ac_val[i + 8] * qscale_table[xy], s->qscale);
             }
         }
     }
     /* left copy */
-    for(i=1;i<8;i++)
-        ac_val1[i    ] = block[s->dsp.idct_permutation[i<<3]];
+    for (i = 1; i < 8; i++)
+        ac_val1[i] = block[s->idsp.idct_permutation[i << 3]];
 
     /* top copy */
-    for(i=1;i<8;i++)
-        ac_val1[8 + i] = block[s->dsp.idct_permutation[i   ]];
-
+    for (i = 1; i < 8; i++)
+        ac_val1[8 + i] = block[s->idsp.idct_permutation[i]];
 }
 
 /**
  * check if the next stuff is a resync marker or the end.
  * @return 0 if not
  */
-static inline int mpeg4_is_resync(MpegEncContext *s){
-    int bits_count= get_bits_count(&s->gb);
-    int v= show_bits(&s->gb, 16);
+static inline int mpeg4_is_resync(MpegEncContext *s)
+{
+    int bits_count = get_bits_count(&s->gb);
+    int v          = show_bits(&s->gb, 16);
 
-    if(s->workaround_bugs&FF_BUG_NO_PADDING){
+    if (s->workaround_bugs & FF_BUG_NO_PADDING)
         return 0;
-    }
 
-    while(v<=0xFF){
-        if(s->pict_type==AV_PICTURE_TYPE_B || (v>>(8-s->pict_type)!=1) || s->partitioned_frame)
+    while (v <= 0xFF) {
+        if (s->pict_type == AV_PICTURE_TYPE_B ||
+            (v >> (8 - s->pict_type) != 1) || s->partitioned_frame)
             break;
-        skip_bits(&s->gb, 8+s->pict_type);
-        bits_count+= 8+s->pict_type;
-        v= show_bits(&s->gb, 16);
+        skip_bits(&s->gb, 8 + s->pict_type);
+        bits_count += 8 + s->pict_type;
+        v = show_bits(&s->gb, 16);
     }
 
-    if(bits_count + 8 >= s->gb.size_in_bits){
-        v>>=8;
-        v|= 0x7F >> (7-(bits_count&7));
+    if (bits_count + 8 >= s->gb.size_in_bits) {
+        v >>= 8;
+        v  |= 0x7F >> (7 - (bits_count & 7));
 
-        if(v==0x7F)
+        if (v == 0x7F)
             return 1;
-    }else{
-        if(v == ff_mpeg4_resync_prefix[bits_count&7]){
+    } else {
+        if (v == ff_mpeg4_resync_prefix[bits_count & 7]) {
             int len;
-            GetBitContext gb= s->gb;
+            GetBitContext gb = s->gb;
 
             skip_bits(&s->gb, 1);
             align_get_bits(&s->gb);
 
-            for(len=0; len<32; len++){
-                if(get_bits1(&s->gb)) break;
-            }
+            for (len = 0; len < 32; len++)
+                if (get_bits1(&s->gb))
+                    break;
 
-            s->gb= gb;
+            s->gb = gb;
 
-            if(len>=ff_mpeg4_get_video_packet_prefix_length(s))
+            if (len >= ff_mpeg4_get_video_packet_prefix_length(s))
                 return 1;
         }
     }
     return 0;
 }
 
-static void mpeg4_decode_sprite_trajectory(MpegEncContext * s, GetBitContext *gb)
+static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *gb)
 {
-    int i;
-    int a= 2<<s->sprite_warping_accuracy;
-    int rho= 3-s->sprite_warping_accuracy;
-    int r=16/a;
-    const int vop_ref[4][2]= {{0,0}, {s->width,0}, {0, s->height}, {s->width, s->height}}; // only true for rectangle shapes
-    int d[4][2]={{0,0}, {0,0}, {0,0}, {0,0}};
+    MpegEncContext *s = &ctx->m;
+    int a     = 2 << s->sprite_warping_accuracy;
+    int rho   = 3  - s->sprite_warping_accuracy;
+    int r     = 16 / a;
+    int alpha = 0;
+    int beta  = 0;
+    int w     = s->width;
+    int h     = s->height;
+    int min_ab, i, w2, h2, w3, h3;
     int sprite_ref[4][2];
     int virtual_ref[2][2];
-    int w2, h2, w3, h3;
-    int alpha=0, beta=0;
-    int w= s->width;
-    int h= s->height;
-    int min_ab;
 
-    for(i=0; i<s->num_sprite_warping_points; i++){
+    // only true for rectangle shapes
+    const int vop_ref[4][2] = { { 0, 0 },         { s->width, 0 },
+                                { 0, s->height }, { s->width, s->height } };
+    int d[4][2]             = { { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } };
+
+    if (w <= 0 || h <= 0)
+        return AVERROR_INVALIDDATA;
+
+    for (i = 0; i < ctx->num_sprite_warping_points; i++) {
         int length;
-        int x=0, y=0;
+        int x = 0, y = 0;
 
-        length= get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
-        if(length){
-            x= get_xbits(gb, length);
-        }
-        if(!(s->divx_version==500 && s->divx_build==413)) skip_bits1(gb); /* marker bit */
+        length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
+        if (length)
+            x = get_xbits(gb, length);
 
-        length= get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
-        if(length){
-            y=get_xbits(gb, length);
-        }
-        skip_bits1(gb); /* marker bit */
-        s->sprite_traj[i][0]= d[i][0]= x;
-        s->sprite_traj[i][1]= d[i][1]= y;
+        if (!(ctx->divx_version == 500 && ctx->divx_build == 413))
+            skip_bits1(gb);     /* marker bit */
+
+        length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
+        if (length)
+            y = get_xbits(gb, length);
+
+        skip_bits1(gb);         /* marker bit */
+        ctx->sprite_traj[i][0] = d[i][0] = x;
+        ctx->sprite_traj[i][1] = d[i][1] = y;
     }
-    for(; i<4; i++)
-        s->sprite_traj[i][0]= s->sprite_traj[i][1]= 0;
-
-    while((1<<alpha)<w) alpha++;
-    while((1<<beta )<h) beta++; // there seems to be a typo in the mpeg4 std for the definition of w' and h'
-    w2= 1<<alpha;
-    h2= 1<<beta;
-
-// Note, the 4th point isn't used for GMC
-    if(s->divx_version==500 && s->divx_build==413){
-        sprite_ref[0][0]= a*vop_ref[0][0] + d[0][0];
-        sprite_ref[0][1]= a*vop_ref[0][1] + d[0][1];
-        sprite_ref[1][0]= a*vop_ref[1][0] + d[0][0] + d[1][0];
-        sprite_ref[1][1]= a*vop_ref[1][1] + d[0][1] + d[1][1];
-        sprite_ref[2][0]= a*vop_ref[2][0] + d[0][0] + d[2][0];
-        sprite_ref[2][1]= a*vop_ref[2][1] + d[0][1] + d[2][1];
+    for (; i < 4; i++)
+        ctx->sprite_traj[i][0] = ctx->sprite_traj[i][1] = 0;
+
+    while ((1 << alpha) < w)
+        alpha++;
+    while ((1 << beta) < h)
+        beta++;  /* typo in the mpeg4 std for the definition of w' and h' */
+    w2 = 1 << alpha;
+    h2 = 1 << beta;
+
+    // Note, the 4th point isn't used for GMC
+    if (ctx->divx_version == 500 && ctx->divx_build == 413) {
+        sprite_ref[0][0] = a * vop_ref[0][0] + d[0][0];
+        sprite_ref[0][1] = a * vop_ref[0][1] + d[0][1];
+        sprite_ref[1][0] = a * vop_ref[1][0] + d[0][0] + d[1][0];
+        sprite_ref[1][1] = a * vop_ref[1][1] + d[0][1] + d[1][1];
+        sprite_ref[2][0] = a * vop_ref[2][0] + d[0][0] + d[2][0];
+        sprite_ref[2][1] = a * vop_ref[2][1] + d[0][1] + d[2][1];
     } else {
-        sprite_ref[0][0]= (a>>1)*(2*vop_ref[0][0] + d[0][0]);
-        sprite_ref[0][1]= (a>>1)*(2*vop_ref[0][1] + d[0][1]);
-        sprite_ref[1][0]= (a>>1)*(2*vop_ref[1][0] + d[0][0] + d[1][0]);
-        sprite_ref[1][1]= (a>>1)*(2*vop_ref[1][1] + d[0][1] + d[1][1]);
-        sprite_ref[2][0]= (a>>1)*(2*vop_ref[2][0] + d[0][0] + d[2][0]);
-        sprite_ref[2][1]= (a>>1)*(2*vop_ref[2][1] + d[0][1] + d[2][1]);
+        sprite_ref[0][0] = (a >> 1) * (2 * vop_ref[0][0] + d[0][0]);
+        sprite_ref[0][1] = (a >> 1) * (2 * vop_ref[0][1] + d[0][1]);
+        sprite_ref[1][0] = (a >> 1) * (2 * vop_ref[1][0] + d[0][0] + d[1][0]);
+        sprite_ref[1][1] = (a >> 1) * (2 * vop_ref[1][1] + d[0][1] + d[1][1]);
+        sprite_ref[2][0] = (a >> 1) * (2 * vop_ref[2][0] + d[0][0] + d[2][0]);
+        sprite_ref[2][1] = (a >> 1) * (2 * vop_ref[2][1] + d[0][1] + d[2][1]);
     }
-/*    sprite_ref[3][0]= (a>>1)*(2*vop_ref[3][0] + d[0][0] + d[1][0] + d[2][0] + d[3][0]);
-    sprite_ref[3][1]= (a>>1)*(2*vop_ref[3][1] + d[0][1] + d[1][1] + d[2][1] + d[3][1]); */
-
-// this is mostly identical to the mpeg4 std (and is totally unreadable because of that ...)
-// perhaps it should be reordered to be more readable ...
-// the idea behind this virtual_ref mess is to be able to use shifts later per pixel instead of divides
-// so the distance between points is converted from w&h based to w2&h2 based which are of the 2^x form
-    virtual_ref[0][0]= 16*(vop_ref[0][0] + w2)
-        + ROUNDED_DIV(((w - w2)*(r*sprite_ref[0][0] - 16*vop_ref[0][0]) + w2*(r*sprite_ref[1][0] - 16*vop_ref[1][0])),w);
-    virtual_ref[0][1]= 16*vop_ref[0][1]
-        + ROUNDED_DIV(((w - w2)*(r*sprite_ref[0][1] - 16*vop_ref[0][1]) + w2*(r*sprite_ref[1][1] - 16*vop_ref[1][1])),w);
-    virtual_ref[1][0]= 16*vop_ref[0][0]
-        + ROUNDED_DIV(((h - h2)*(r*sprite_ref[0][0] - 16*vop_ref[0][0]) + h2*(r*sprite_ref[2][0] - 16*vop_ref[2][0])),h);
-    virtual_ref[1][1]= 16*(vop_ref[0][1] + h2)
-        + ROUNDED_DIV(((h - h2)*(r*sprite_ref[0][1] - 16*vop_ref[0][1]) + h2*(r*sprite_ref[2][1] - 16*vop_ref[2][1])),h);
-
-    switch(s->num_sprite_warping_points)
-    {
-        case 0:
-            s->sprite_offset[0][0]= 0;
-            s->sprite_offset[0][1]= 0;
-            s->sprite_offset[1][0]= 0;
-            s->sprite_offset[1][1]= 0;
-            s->sprite_delta[0][0]= a;
-            s->sprite_delta[0][1]= 0;
-            s->sprite_delta[1][0]= 0;
-            s->sprite_delta[1][1]= a;
-            s->sprite_shift[0]= 0;
-            s->sprite_shift[1]= 0;
-            break;
-        case 1: //GMC only
-            s->sprite_offset[0][0]= sprite_ref[0][0] - a*vop_ref[0][0];
-            s->sprite_offset[0][1]= sprite_ref[0][1] - a*vop_ref[0][1];
-            s->sprite_offset[1][0]= ((sprite_ref[0][0]>>1)|(sprite_ref[0][0]&1)) - a*(vop_ref[0][0]/2);
-            s->sprite_offset[1][1]= ((sprite_ref[0][1]>>1)|(sprite_ref[0][1]&1)) - a*(vop_ref[0][1]/2);
-            s->sprite_delta[0][0]= a;
-            s->sprite_delta[0][1]= 0;
-            s->sprite_delta[1][0]= 0;
-            s->sprite_delta[1][1]= a;
-            s->sprite_shift[0]= 0;
-            s->sprite_shift[1]= 0;
-            break;
-        case 2:
-            s->sprite_offset[0][0]= (sprite_ref[0][0]<<(alpha+rho))
-                                                  + (-r*sprite_ref[0][0] + virtual_ref[0][0])*(-vop_ref[0][0])
-                                                  + ( r*sprite_ref[0][1] - virtual_ref[0][1])*(-vop_ref[0][1])
-                                                  + (1<<(alpha+rho-1));
-            s->sprite_offset[0][1]= (sprite_ref[0][1]<<(alpha+rho))
-                                                  + (-r*sprite_ref[0][1] + virtual_ref[0][1])*(-vop_ref[0][0])
-                                                  + (-r*sprite_ref[0][0] + virtual_ref[0][0])*(-vop_ref[0][1])
-                                                  + (1<<(alpha+rho-1));
-            s->sprite_offset[1][0]= ( (-r*sprite_ref[0][0] + virtual_ref[0][0])*(-2*vop_ref[0][0] + 1)
-                                     +( r*sprite_ref[0][1] - virtual_ref[0][1])*(-2*vop_ref[0][1] + 1)
-                                     +2*w2*r*sprite_ref[0][0]
-                                     - 16*w2
-                                     + (1<<(alpha+rho+1)));
-            s->sprite_offset[1][1]= ( (-r*sprite_ref[0][1] + virtual_ref[0][1])*(-2*vop_ref[0][0] + 1)
-                                     +(-r*sprite_ref[0][0] + virtual_ref[0][0])*(-2*vop_ref[0][1] + 1)
-                                     +2*w2*r*sprite_ref[0][1]
-                                     - 16*w2
-                                     + (1<<(alpha+rho+1)));
-            s->sprite_delta[0][0]=   (-r*sprite_ref[0][0] + virtual_ref[0][0]);
-            s->sprite_delta[0][1]=   (+r*sprite_ref[0][1] - virtual_ref[0][1]);
-            s->sprite_delta[1][0]=   (-r*sprite_ref[0][1] + virtual_ref[0][1]);
-            s->sprite_delta[1][1]=   (-r*sprite_ref[0][0] + virtual_ref[0][0]);
-
-            s->sprite_shift[0]= alpha+rho;
-            s->sprite_shift[1]= alpha+rho+2;
-            break;
-        case 3:
-            min_ab= FFMIN(alpha, beta);
-            w3= w2>>min_ab;
-            h3= h2>>min_ab;
-            s->sprite_offset[0][0]=  (sprite_ref[0][0]<<(alpha+beta+rho-min_ab))
-                                   + (-r*sprite_ref[0][0] + virtual_ref[0][0])*h3*(-vop_ref[0][0])
-                                   + (-r*sprite_ref[0][0] + virtual_ref[1][0])*w3*(-vop_ref[0][1])
-                                   + (1<<(alpha+beta+rho-min_ab-1));
-            s->sprite_offset[0][1]=  (sprite_ref[0][1]<<(alpha+beta+rho-min_ab))
-                                   + (-r*sprite_ref[0][1] + virtual_ref[0][1])*h3*(-vop_ref[0][0])
-                                   + (-r*sprite_ref[0][1] + virtual_ref[1][1])*w3*(-vop_ref[0][1])
-                                   + (1<<(alpha+beta+rho-min_ab-1));
-            s->sprite_offset[1][0]=  (-r*sprite_ref[0][0] + virtual_ref[0][0])*h3*(-2*vop_ref[0][0] + 1)
-                                   + (-r*sprite_ref[0][0] + virtual_ref[1][0])*w3*(-2*vop_ref[0][1] + 1)
-                                   + 2*w2*h3*r*sprite_ref[0][0]
-                                   - 16*w2*h3
-                                   + (1<<(alpha+beta+rho-min_ab+1));
-            s->sprite_offset[1][1]=  (-r*sprite_ref[0][1] + virtual_ref[0][1])*h3*(-2*vop_ref[0][0] + 1)
-                                   + (-r*sprite_ref[0][1] + virtual_ref[1][1])*w3*(-2*vop_ref[0][1] + 1)
-                                   + 2*w2*h3*r*sprite_ref[0][1]
-                                   - 16*w2*h3
-                                   + (1<<(alpha+beta+rho-min_ab+1));
-            s->sprite_delta[0][0]=   (-r*sprite_ref[0][0] + virtual_ref[0][0])*h3;
-            s->sprite_delta[0][1]=   (-r*sprite_ref[0][0] + virtual_ref[1][0])*w3;
-            s->sprite_delta[1][0]=   (-r*sprite_ref[0][1] + virtual_ref[0][1])*h3;
-            s->sprite_delta[1][1]=   (-r*sprite_ref[0][1] + virtual_ref[1][1])*w3;
-
-            s->sprite_shift[0]= alpha + beta + rho - min_ab;
-            s->sprite_shift[1]= alpha + beta + rho - min_ab + 2;
-            break;
+    /* sprite_ref[3][0] = (a >> 1) * (2 * vop_ref[3][0] + d[0][0] + d[1][0] + d[2][0] + d[3][0]);
+     * sprite_ref[3][1] = (a >> 1) * (2 * vop_ref[3][1] + d[0][1] + d[1][1] + d[2][1] + d[3][1]); */
+
+    /* this is mostly identical to the mpeg4 std (and is totally unreadable
+     * because of that...). Perhaps it should be reordered to be more readable.
+     * The idea behind this virtual_ref mess is to be able to use shifts later
+     * per pixel instead of divides so the distance between points is converted
+     * from w&h based to w2&h2 based which are of the 2^x form. */
+    virtual_ref[0][0] = 16 * (vop_ref[0][0] + w2) +
+                         ROUNDED_DIV(((w - w2) *
+                                      (r * sprite_ref[0][0] - 16 * vop_ref[0][0]) +
+                                      w2 * (r * sprite_ref[1][0] - 16 * vop_ref[1][0])), w);
+    virtual_ref[0][1] = 16 * vop_ref[0][1] +
+                        ROUNDED_DIV(((w - w2) *
+                                     (r * sprite_ref[0][1] - 16 * vop_ref[0][1]) +
+                                     w2 * (r * sprite_ref[1][1] - 16 * vop_ref[1][1])), w);
+    virtual_ref[1][0] = 16 * vop_ref[0][0] +
+                        ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][0] - 16 * vop_ref[0][0]) +
+                                     h2 * (r * sprite_ref[2][0] - 16 * vop_ref[2][0])), h);
+    virtual_ref[1][1] = 16 * (vop_ref[0][1] + h2) +
+                        ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][1] - 16 * vop_ref[0][1]) +
+                                     h2 * (r * sprite_ref[2][1] - 16 * vop_ref[2][1])), h);
+
+    switch (ctx->num_sprite_warping_points) {
+    case 0:
+        s->sprite_offset[0][0] =
+        s->sprite_offset[0][1] =
+        s->sprite_offset[1][0] =
+        s->sprite_offset[1][1] = 0;
+        s->sprite_delta[0][0]  = a;
+        s->sprite_delta[0][1]  =
+        s->sprite_delta[1][0]  = 0;
+        s->sprite_delta[1][1]  = a;
+        ctx->sprite_shift[0]   =
+        ctx->sprite_shift[1]   = 0;
+        break;
+    case 1:     // GMC only
+        s->sprite_offset[0][0] = sprite_ref[0][0] - a * vop_ref[0][0];
+        s->sprite_offset[0][1] = sprite_ref[0][1] - a * vop_ref[0][1];
+        s->sprite_offset[1][0] = ((sprite_ref[0][0] >> 1) | (sprite_ref[0][0] & 1)) -
+                                 a * (vop_ref[0][0] / 2);
+        s->sprite_offset[1][1] = ((sprite_ref[0][1] >> 1) | (sprite_ref[0][1] & 1)) -
+                                 a * (vop_ref[0][1] / 2);
+        s->sprite_delta[0][0]  = a;
+        s->sprite_delta[0][1]  =
+        s->sprite_delta[1][0]  = 0;
+        s->sprite_delta[1][1]  = a;
+        ctx->sprite_shift[0]   =
+        ctx->sprite_shift[1]   = 0;
+        break;
+    case 2:
+        s->sprite_offset[0][0] = (sprite_ref[0][0] << (alpha + rho)) +
+                                 (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
+                                 (-vop_ref[0][0]) +
+                                 (r * sprite_ref[0][1] - virtual_ref[0][1]) *
+                                 (-vop_ref[0][1]) + (1 << (alpha + rho - 1));
+        s->sprite_offset[0][1] = (sprite_ref[0][1] << (alpha + rho)) +
+                                 (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
+                                 (-vop_ref[0][0]) +
+                                 (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
+                                 (-vop_ref[0][1]) + (1 << (alpha + rho - 1));
+        s->sprite_offset[1][0] = ((-r * sprite_ref[0][0] + virtual_ref[0][0]) *
+                                  (-2 * vop_ref[0][0] + 1) +
+                                  (r * sprite_ref[0][1] - virtual_ref[0][1]) *
+                                  (-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
+                                  sprite_ref[0][0] - 16 * w2 + (1 << (alpha + rho + 1)));
+        s->sprite_offset[1][1] = ((-r * sprite_ref[0][1] + virtual_ref[0][1]) *
+                                  (-2 * vop_ref[0][0] + 1) +
+                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
+                                  (-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
+                                  sprite_ref[0][1] - 16 * w2 + (1 << (alpha + rho + 1)));
+        s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
+        s->sprite_delta[0][1] = (+r * sprite_ref[0][1] - virtual_ref[0][1]);
+        s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]);
+        s->sprite_delta[1][1] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
+
+        ctx->sprite_shift[0]  = alpha + rho;
+        ctx->sprite_shift[1]  = alpha + rho + 2;
+        break;
+    case 3:
+        min_ab = FFMIN(alpha, beta);
+        w3     = w2 >> min_ab;
+        h3     = h2 >> min_ab;
+        s->sprite_offset[0][0] = (sprite_ref[0][0] << (alpha + beta + rho - min_ab)) +
+                                 (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
+                                 h3 * (-vop_ref[0][0]) +
+                                 (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
+                                 w3 * (-vop_ref[0][1]) +
+                                 (1 << (alpha + beta + rho - min_ab - 1));
+        s->sprite_offset[0][1] = (sprite_ref[0][1] << (alpha + beta + rho - min_ab)) +
+                                 (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
+                                 h3 * (-vop_ref[0][0]) +
+                                 (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
+                                 w3 * (-vop_ref[0][1]) +
+                                 (1 << (alpha + beta + rho - min_ab - 1));
+        s->sprite_offset[1][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
+                                 h3 * (-2 * vop_ref[0][0] + 1) +
+                                 (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
+                                 w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
+                                 r * sprite_ref[0][0] - 16 * w2 * h3 +
+                                 (1 << (alpha + beta + rho - min_ab + 1));
+        s->sprite_offset[1][1] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
+                                 h3 * (-2 * vop_ref[0][0] + 1) +
+                                 (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
+                                 w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
+                                 r * sprite_ref[0][1] - 16 * w2 * h3 +
+                                 (1 << (alpha + beta + rho - min_ab + 1));
+        s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3;
+        s->sprite_delta[0][1] = (-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3;
+        s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3;
+        s->sprite_delta[1][1] = (-r * sprite_ref[0][1] + virtual_ref[1][1]) * w3;
+
+        ctx->sprite_shift[0]  = alpha + beta + rho - min_ab;
+        ctx->sprite_shift[1]  = alpha + beta + rho - min_ab + 2;
+        break;
     }
     /* try to simplify the situation */
-    if(   s->sprite_delta[0][0] == a<<s->sprite_shift[0]
-       && s->sprite_delta[0][1] == 0
-       && s->sprite_delta[1][0] == 0
-       && s->sprite_delta[1][1] == a<<s->sprite_shift[0])
-    {
-        s->sprite_offset[0][0]>>=s->sprite_shift[0];
-        s->sprite_offset[0][1]>>=s->sprite_shift[0];
-        s->sprite_offset[1][0]>>=s->sprite_shift[1];
-        s->sprite_offset[1][1]>>=s->sprite_shift[1];
-        s->sprite_delta[0][0]= a;
-        s->sprite_delta[0][1]= 0;
-        s->sprite_delta[1][0]= 0;
-        s->sprite_delta[1][1]= a;
-        s->sprite_shift[0]= 0;
-        s->sprite_shift[1]= 0;
-        s->real_sprite_warping_points=1;
-    }
-    else{
-        int shift_y= 16 - s->sprite_shift[0];
-        int shift_c= 16 - s->sprite_shift[1];
-        for(i=0; i<2; i++){
-            s->sprite_offset[0][i]<<= shift_y;
-            s->sprite_offset[1][i]<<= shift_c;
-            s->sprite_delta[0][i]<<= shift_y;
-            s->sprite_delta[1][i]<<= shift_y;
-            s->sprite_shift[i]= 16;
+    if (s->sprite_delta[0][0] == a << ctx->sprite_shift[0] &&
+        s->sprite_delta[0][1] == 0 &&
+        s->sprite_delta[1][0] == 0 &&
+        s->sprite_delta[1][1] == a << ctx->sprite_shift[0]) {
+        s->sprite_offset[0][0] >>= ctx->sprite_shift[0];
+        s->sprite_offset[0][1] >>= ctx->sprite_shift[0];
+        s->sprite_offset[1][0] >>= ctx->sprite_shift[1];
+        s->sprite_offset[1][1] >>= ctx->sprite_shift[1];
+        s->sprite_delta[0][0] = a;
+        s->sprite_delta[0][1] = 0;
+        s->sprite_delta[1][0] = 0;
+        s->sprite_delta[1][1] = a;
+        ctx->sprite_shift[0] = 0;
+        ctx->sprite_shift[1] = 0;
+        s->real_sprite_warping_points = 1;
+    } else {
+        int shift_y = 16 - ctx->sprite_shift[0];
+        int shift_c = 16 - ctx->sprite_shift[1];
+        for (i = 0; i < 2; i++) {
+            s->sprite_offset[0][i] <<= shift_y;
+            s->sprite_offset[1][i] <<= shift_c;
+            s->sprite_delta[0][i]  <<= shift_y;
+            s->sprite_delta[1][i]  <<= shift_y;
+            ctx->sprite_shift[i]     = 16;
         }
-        s->real_sprite_warping_points= s->num_sprite_warping_points;
+        s->real_sprite_warping_points = ctx->num_sprite_warping_points;
     }
+
+    return 0;
 }
 
 /**
  * Decode the next video packet.
  * @return <0 if something went wrong
  */
-int ff_mpeg4_decode_video_packet_header(MpegEncContext *s)
+int ff_mpeg4_decode_video_packet_header(Mpeg4DecContext *ctx)
 {
-    int mb_num_bits= av_log2(s->mb_num - 1) + 1;
-    int header_extension=0, mb_num, len;
+    MpegEncContext *s = &ctx->m;
+
+    int mb_num_bits      = av_log2(s->mb_num - 1) + 1;
+    int header_extension = 0, mb_num, len;
 
     /* is there enough space left for a video packet + header */
-    if( get_bits_count(&s->gb) > s->gb.size_in_bits-20) return -1;
+    if (get_bits_count(&s->gb) > s->gb.size_in_bits - 20)
+        return -1;
 
-    for(len=0; len<32; len++){
-        if(get_bits1(&s->gb)) break;
-    }
+    for (len = 0; len < 32; len++)
+        if (get_bits1(&s->gb))
+            break;
 
-    if(len!=ff_mpeg4_get_video_packet_prefix_length(s)){
+    if (len != ff_mpeg4_get_video_packet_prefix_length(s)) {
         av_log(s->avctx, AV_LOG_ERROR, "marker does not match f_code\n");
         return -1;
     }
 
-    if(s->shape != RECT_SHAPE){
-        header_extension= get_bits1(&s->gb);
-        //FIXME more stuff here
+    if (ctx->shape != RECT_SHAPE) {
+        header_extension = get_bits1(&s->gb);
+        // FIXME more stuff here
     }
 
-    mb_num= get_bits(&s->gb, mb_num_bits);
-    if(mb_num>=s->mb_num){
-        av_log(s->avctx, AV_LOG_ERROR, "illegal mb_num in video packet (%d %d) \n", mb_num, s->mb_num);
+    mb_num = get_bits(&s->gb, mb_num_bits);
+    if (mb_num >= s->mb_num) {
+        av_log(s->avctx, AV_LOG_ERROR,
+               "illegal mb_num in video packet (%d %d) \n", mb_num, s->mb_num);
         return -1;
     }
-    if(s->pict_type == AV_PICTURE_TYPE_B){
+    if (s->pict_type == AV_PICTURE_TYPE_B) {
         int mb_x = 0, mb_y = 0;
 
-        while (s->next_picture.f.mbskip_table[s->mb_index2xy[mb_num]]) {
+        while (s->next_picture.mbskip_table[s->mb_index2xy[mb_num]]) {
             if (!mb_x)
-                ff_thread_await_progress(&s->next_picture_ptr->f, mb_y++, 0);
+                ff_thread_await_progress(&s->next_picture_ptr->tf, mb_y++, 0);
             mb_num++;
-            if (++mb_x == s->mb_width) mb_x = 0;
+            if (++mb_x == s->mb_width)
+                mb_x = 0;
         }
-        if(mb_num >= s->mb_num) return -1; // slice contains just skipped MBs which where already decoded
+        if (mb_num >= s->mb_num)
+            return -1;  // slice contains just skipped MBs (already decoded)
     }
 
-    s->mb_x= mb_num % s->mb_width;
-    s->mb_y= mb_num / s->mb_width;
+    s->mb_x = mb_num % s->mb_width;
+    s->mb_y = mb_num / s->mb_width;
 
-    if(s->shape != BIN_ONLY_SHAPE){
-        int qscale= get_bits(&s->gb, s->quant_precision);
-        if(qscale)
-            s->chroma_qscale=s->qscale= qscale;
+    if (ctx->shape != BIN_ONLY_SHAPE) {
+        int qscale = get_bits(&s->gb, s->quant_precision);
+        if (qscale)
+            s->chroma_qscale = s->qscale = qscale;
     }
 
-    if(s->shape == RECT_SHAPE){
-        header_extension= get_bits1(&s->gb);
-    }
-    if(header_extension){
-        int time_incr=0;
+    if (ctx->shape == RECT_SHAPE)
+        header_extension = get_bits1(&s->gb);
+
+    if (header_extension) {
+        int time_incr = 0;
 
         while (get_bits1(&s->gb) != 0)
             time_incr++;
 
         check_marker(&s->gb, "before time_increment in video packed header");
-        skip_bits(&s->gb, s->time_increment_bits); /* time_increment */
+        skip_bits(&s->gb, ctx->time_increment_bits);      /* time_increment */
         check_marker(&s->gb, "before vop_coding_type in video packed header");
 
         skip_bits(&s->gb, 2); /* vop coding type */
-        //FIXME not rect stuff here
+        // FIXME not rect stuff here
 
-        if(s->shape != BIN_ONLY_SHAPE){
+        if (ctx->shape != BIN_ONLY_SHAPE) {
             skip_bits(&s->gb, 3); /* intra dc vlc threshold */
-//FIXME don't just ignore everything
-            if(s->pict_type == AV_PICTURE_TYPE_S && s->vol_sprite_usage==GMC_SPRITE){
-                mpeg4_decode_sprite_trajectory(s, &s->gb);
+            // FIXME don't just ignore everything
+            if (s->pict_type == AV_PICTURE_TYPE_S &&
+                ctx->vol_sprite_usage == GMC_SPRITE) {
+                if (mpeg4_decode_sprite_trajectory(ctx, &s->gb) < 0)
+                    return AVERROR_INVALIDDATA;
                 av_log(s->avctx, AV_LOG_ERROR, "untested\n");
             }
 
-            //FIXME reduced res stuff here
+            // FIXME reduced res stuff here
 
             if (s->pict_type != AV_PICTURE_TYPE_I) {
                 int f_code = get_bits(&s->gb, 3);       /* fcode_for */
-                if(f_code==0){
-                    av_log(s->avctx, AV_LOG_ERROR, "Error, video packet header damaged (f_code=0)\n");
-                }
+                if (f_code == 0)
+                    av_log(s->avctx, AV_LOG_ERROR,
+                           "Error, video packet header damaged (f_code=0)\n");
             }
             if (s->pict_type == AV_PICTURE_TYPE_B) {
                 int b_code = get_bits(&s->gb, 3);
-                if(b_code==0){
-                    av_log(s->avctx, AV_LOG_ERROR, "Error, video packet header damaged (b_code=0)\n");
-                }
+                if (b_code == 0)
+                    av_log(s->avctx, AV_LOG_ERROR,
+                           "Error, video packet header damaged (b_code=0)\n");
             }
         }
     }
-    //FIXME new-pred stuff
+    // FIXME new-pred stuff
 
     return 0;
 }
@@ -445,43 +478,49 @@ int ff_mpeg4_decode_video_packet_header(MpegEncContext *s)
  * @param n either 0 for the x component or 1 for y
  * @return the average MV for a GMC MB
  */
-static inline int get_amv(MpegEncContext *s, int n){
+static inline int get_amv(Mpeg4DecContext *ctx, int n)
+{
+    MpegEncContext *s = &ctx->m;
     int x, y, mb_v, sum, dx, dy, shift;
-    int len = 1 << (s->f_code + 4);
-    const int a= s->sprite_warping_accuracy;
+    int len     = 1 << (s->f_code + 4);
+    const int a = s->sprite_warping_accuracy;
 
-    if(s->workaround_bugs & FF_BUG_AMV)
+    if (s->workaround_bugs & FF_BUG_AMV)
         len >>= s->quarter_sample;
 
-    if(s->real_sprite_warping_points==1){
-        if(s->divx_version==500 && s->divx_build==413)
-            sum= s->sprite_offset[0][n] / (1<<(a - s->quarter_sample));
+    if (s->real_sprite_warping_points == 1) {
+        if (ctx->divx_version == 500 && ctx->divx_build == 413)
+            sum = s->sprite_offset[0][n] / (1 << (a - s->quarter_sample));
         else
-            sum= RSHIFT(s->sprite_offset[0][n]<<s->quarter_sample, a);
-    }else{
-        dx= s->sprite_delta[n][0];
-        dy= s->sprite_delta[n][1];
-        shift= s->sprite_shift[0];
-        if(n) dy -= 1<<(shift + a + 1);
-        else  dx -= 1<<(shift + a + 1);
-        mb_v= s->sprite_offset[0][n] + dx*s->mb_x*16 + dy*s->mb_y*16;
-
-        sum=0;
-        for(y=0; y<16; y++){
+            sum = RSHIFT(s->sprite_offset[0][n] << s->quarter_sample, a);
+    } else {
+        dx    = s->sprite_delta[n][0];
+        dy    = s->sprite_delta[n][1];
+        shift = ctx->sprite_shift[0];
+        if (n)
+            dy -= 1 << (shift + a + 1);
+        else
+            dx -= 1 << (shift + a + 1);
+        mb_v = s->sprite_offset[0][n] + dx * s->mb_x * 16 + dy * s->mb_y * 16;
+
+        sum = 0;
+        for (y = 0; y < 16; y++) {
             int v;
 
-            v= mb_v + dy*y;
-            //XXX FIXME optimize
-            for(x=0; x<16; x++){
-                sum+= v>>shift;
-                v+= dx;
+            v = mb_v + dy * y;
+            // FIXME optimize
+            for (x = 0; x < 16; x++) {
+                sum += v >> shift;
+                v   += dx;
             }
         }
-        sum= RSHIFT(sum, a+8-s->quarter_sample);
+        sum = RSHIFT(sum, a + 8 - s->quarter_sample);
     }
 
-    if      (sum < -len) sum= -len;
-    else if (sum >= len) sum= len-1;
+    if (sum < -len)
+        sum = -len;
+    else if (sum >= len)
+        sum = len - 1;
 
     return sum;
 }
@@ -492,7 +531,7 @@ static inline int get_amv(MpegEncContext *s, int n){
  * @param dir_ptr the prediction direction will be stored here
  * @return the quantized dc
  */
-static inline int mpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr)
+static inline int mpeg4_decode_dc(MpegEncContext *s, int n, int *dir_ptr)
 {
     int level, code;
 
@@ -500,29 +539,31 @@ static inline int mpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr)
         code = get_vlc2(&s->gb, dc_lum.table, DC_VLC_BITS, 1);
     else
         code = get_vlc2(&s->gb, dc_chrom.table, DC_VLC_BITS, 1);
-    if (code < 0 || code > 9 /* && s->nbit<9 */){
+
+    if (code < 0 || code > 9 /* && s->nbit < 9 */) {
         av_log(s->avctx, AV_LOG_ERROR, "illegal dc vlc\n");
         return -1;
     }
+
     if (code == 0) {
         level = 0;
     } else {
-        if(IS_3IV1){
-            if(code==1)
-                level= 2*get_bits1(&s->gb)-1;
-            else{
-                if(get_bits1(&s->gb))
-                    level = get_bits(&s->gb, code-1) + (1<<(code-1));
+        if (IS_3IV1) {
+            if (code == 1)
+                level = 2 * get_bits1(&s->gb) - 1;
+            else {
+                if (get_bits1(&s->gb))
+                    level = get_bits(&s->gb, code - 1) + (1 << (code - 1));
                 else
-                    level = -get_bits(&s->gb, code-1) - (1<<(code-1));
+                    level = -get_bits(&s->gb, code - 1) - (1 << (code - 1));
             }
-        }else{
+        } else {
             level = get_xbits(&s->gb, code);
         }
 
-        if (code > 8){
-            if(get_bits1(&s->gb)==0){ /* marker */
-                if(s->err_recognition&AV_EF_BITSTREAM){
+        if (code > 8) {
+            if (get_bits1(&s->gb) == 0) { /* marker */
+                if (s->err_recognition & AV_EF_BITSTREAM) {
                     av_log(s->avctx, AV_LOG_ERROR, "dc marker bit missing\n");
                     return -1;
                 }
@@ -537,124 +578,145 @@ static inline int mpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr)
  * Decode first partition.
  * @return number of MBs decoded or <0 if an error occurred
  */
-static int mpeg4_decode_partition_a(MpegEncContext *s){
-    int mb_num;
+static int mpeg4_decode_partition_a(Mpeg4DecContext *ctx)
+{
+    MpegEncContext *s = &ctx->m;
+    int mb_num = 0;
     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 
     /* decode first partition */
-    mb_num=0;
-    s->first_slice_line=1;
-    for(; s->mb_y<s->mb_height; s->mb_y++){
+    s->first_slice_line = 1;
+    for (; s->mb_y < s->mb_height; s->mb_y++) {
         ff_init_block_index(s);
-        for(; s->mb_x<s->mb_width; s->mb_x++){
-            const int xy= s->mb_x + s->mb_y*s->mb_stride;
+        for (; s->mb_x < s->mb_width; s->mb_x++) {
+            const int xy = s->mb_x + s->mb_y * s->mb_stride;
             int cbpc;
-            int dir=0;
+            int dir = 0;
 
             mb_num++;
             ff_update_block_index(s);
-            if(s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y+1)
-                s->first_slice_line=0;
+            if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
+                s->first_slice_line = 0;
 
-            if(s->pict_type==AV_PICTURE_TYPE_I){
+            if (s->pict_type == AV_PICTURE_TYPE_I) {
                 int i;
 
-                do{
-                    if(show_bits_long(&s->gb, 19)==DC_MARKER){
-                        return mb_num-1;
-                    }
+                do {
+                    if (show_bits_long(&s->gb, 19) == DC_MARKER)
+                        return mb_num - 1;
 
                     cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
-                    if (cbpc < 0){
-                        av_log(s->avctx, AV_LOG_ERROR, "cbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
+                    if (cbpc < 0) {
+                        av_log(s->avctx, AV_LOG_ERROR,
+                               "cbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
                         return -1;
                     }
-                }while(cbpc == 8);
+                } while (cbpc == 8);
 
-                s->cbp_table[xy]= cbpc & 3;
-                s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
-                s->mb_intra = 1;
+                s->cbp_table[xy]               = cbpc & 3;
+                s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
+                s->mb_intra                    = 1;
 
-                if(cbpc & 4) {
+                if (cbpc & 4)
                     ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
-                }
-                s->current_picture.f.qscale_table[xy]= s->qscale;
 
-                s->mbintra_table[xy]= 1;
-                for(i=0; i<6; i++){
+                s->current_picture.qscale_table[xy] = s->qscale;
+
+                s->mbintra_table[xy] = 1;
+                for (i = 0; i < 6; i++) {
                     int dc_pred_dir;
-                    int dc= mpeg4_decode_dc(s, i, &dc_pred_dir);
-                    if(dc < 0){
-                        av_log(s->avctx, AV_LOG_ERROR, "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
+                    int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
+                    if (dc < 0) {
+                        av_log(s->avctx, AV_LOG_ERROR,
+                               "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
                         return -1;
                     }
-                    dir<<=1;
-                    if(dc_pred_dir) dir|=1;
+                    dir <<= 1;
+                    if (dc_pred_dir)
+                        dir |= 1;
                 }
-                s->pred_dir_table[xy]= dir;
-            }else{ /* P/S_TYPE */
+                s->pred_dir_table[xy] = dir;
+            } else { /* P/S_TYPE */
                 int mx, my, pred_x, pred_y, bits;
-                int16_t * const mot_val = s->current_picture.f.motion_val[0][s->block_index[0]];
-                const int stride= s->b8_stride*2;
+                int16_t *const mot_val = s->current_picture.motion_val[0][s->block_index[0]];
+                const int stride       = s->b8_stride * 2;
 
 try_again:
-                bits= show_bits(&s->gb, 17);
-                if(bits==MOTION_MARKER){
-                    return mb_num-1;
-                }
+                bits = show_bits(&s->gb, 17);
+                if (bits == MOTION_MARKER)
+                    return mb_num - 1;
+
                 skip_bits1(&s->gb);
-                if(bits&0x10000){
+                if (bits & 0x10000) {
                     /* skip mb */
-                    if(s->pict_type==AV_PICTURE_TYPE_S && s->vol_sprite_usage==GMC_SPRITE){
-                        s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_GMC | MB_TYPE_L0;
-                        mx= get_amv(s, 0);
-                        my= get_amv(s, 1);
-                    }else{
-                        s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
-                        mx=my=0;
+                    if (s->pict_type == AV_PICTURE_TYPE_S &&
+                        ctx->vol_sprite_usage == GMC_SPRITE) {
+                        s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
+                                                         MB_TYPE_16x16 |
+                                                         MB_TYPE_GMC   |
+                                                         MB_TYPE_L0;
+                        mx = get_amv(ctx, 0);
+                        my = get_amv(ctx, 1);
+                    } else {
+                        s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
+                                                         MB_TYPE_16x16 |
+                                                         MB_TYPE_L0;
+                        mx = my = 0;
                     }
-                    mot_val[0       ]= mot_val[2       ]=
-                    mot_val[0+stride]= mot_val[2+stride]= mx;
-                    mot_val[1       ]= mot_val[3       ]=
-                    mot_val[1+stride]= mot_val[3+stride]= my;
-
-                    if(s->mbintra_table[xy])
+                    mot_val[0]          =
+                    mot_val[2]          =
+                    mot_val[0 + stride] =
+                    mot_val[2 + stride] = mx;
+                    mot_val[1]          =
+                    mot_val[3]          =
+                    mot_val[1 + stride] =
+                    mot_val[3 + stride] = my;
+
+                    if (s->mbintra_table[xy])
                         ff_clean_intra_table_entries(s);
                     continue;
                 }
 
                 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
-                if (cbpc < 0){
-                    av_log(s->avctx, AV_LOG_ERROR, "cbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
+                if (cbpc < 0) {
+                    av_log(s->avctx, AV_LOG_ERROR,
+                           "cbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
                     return -1;
                 }
-                if(cbpc == 20)
+                if (cbpc == 20)
                     goto try_again;
 
-                s->cbp_table[xy]= cbpc&(8+3); //8 is dquant
+                s->cbp_table[xy] = cbpc & (8 + 3);  // 8 is dquant
 
                 s->mb_intra = ((cbpc & 4) != 0);
 
-                if(s->mb_intra){
-                    s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
-                    s->mbintra_table[xy]= 1;
-                    mot_val[0       ]= mot_val[2       ]=
-                    mot_val[0+stride]= mot_val[2+stride]= 0;
-                    mot_val[1       ]= mot_val[3       ]=
-                    mot_val[1+stride]= mot_val[3+stride]= 0;
-                }else{
-                    if(s->mbintra_table[xy])
+                if (s->mb_intra) {
+                    s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
+                    s->mbintra_table[xy] = 1;
+                    mot_val[0]          =
+                    mot_val[2]          =
+                    mot_val[0 + stride] =
+                    mot_val[2 + stride] = 0;
+                    mot_val[1]          =
+                    mot_val[3]          =
+                    mot_val[1 + stride] =
+                    mot_val[3 + stride] = 0;
+                } else {
+                    if (s->mbintra_table[xy])
                         ff_clean_intra_table_entries(s);
 
-                    if(s->pict_type==AV_PICTURE_TYPE_S && s->vol_sprite_usage==GMC_SPRITE && (cbpc & 16) == 0)
-                        s->mcsel= get_bits1(&s->gb);
-                    else s->mcsel= 0;
+                    if (s->pict_type == AV_PICTURE_TYPE_S &&
+                        ctx->vol_sprite_usage == GMC_SPRITE &&
+                        (cbpc & 16) == 0)
+                        s->mcsel = get_bits1(&s->gb);
+                    else
+                        s->mcsel = 0;
 
                     if ((cbpc & 16) == 0) {
                         /* 16x16 motion prediction */
 
                         ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
-                        if(!s->mcsel){
+                        if (!s->mcsel) {
                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
                             if (mx >= 0xffff)
                                 return -1;
@@ -662,22 +724,30 @@ try_again:
                             my = ff_h263_decode_motion(s, pred_y, s->f_code);
                             if (my >= 0xffff)
                                 return -1;
-                            s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
+                            s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
+                                                             MB_TYPE_L0;
                         } else {
-                            mx = get_amv(s, 0);
-                            my = get_amv(s, 1);
-                            s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_GMC | MB_TYPE_L0;
+                            mx = get_amv(ctx, 0);
+                            my = get_amv(ctx, 1);
+                            s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
+                                                             MB_TYPE_GMC   |
+                                                             MB_TYPE_L0;
                         }
 
-                        mot_val[0       ]= mot_val[2       ] =
-                        mot_val[0+stride]= mot_val[2+stride]= mx;
-                        mot_val[1       ]= mot_val[3       ]=
-                        mot_val[1+stride]= mot_val[3+stride]= my;
+                        mot_val[0]          =
+                        mot_val[2]          =
+                        mot_val[0 + stride] =
+                        mot_val[2 + stride] = mx;
+                        mot_val[1]          =
+                        mot_val[3]          =
+                        mot_val[1 + stride] =
+                        mot_val[3 + stride] = my;
                     } else {
                         int i;
-                        s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
-                        for(i=0;i<4;i++) {
-                            int16_t *mot_val= ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
+                        s->current_picture.mb_type[xy] = MB_TYPE_8x8 |
+                                                         MB_TYPE_L0;
+                        for (i = 0; i < 4; i++) {
+                            int16_t *mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
                             if (mx >= 0xffff)
                                 return -1;
@@ -692,7 +762,7 @@ try_again:
                 }
             }
         }
-        s->mb_x= 0;
+        s->mb_x = 0;
     }
 
     return mb_num;
@@ -702,85 +772,91 @@ try_again:
  * decode second partition.
  * @return <0 if an error occurred
  */
-static int mpeg4_decode_partition_b(MpegEncContext *s, int mb_count){
-    int mb_num=0;
+static int mpeg4_decode_partition_b(MpegEncContext *s, int mb_count)
+{
+    int mb_num = 0;
     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 
-    s->mb_x= s->resync_mb_x;
-    s->first_slice_line=1;
-    for(s->mb_y= s->resync_mb_y; mb_num < mb_count; s->mb_y++){
+    s->mb_x = s->resync_mb_x;
+    s->first_slice_line = 1;
+    for (s->mb_y = s->resync_mb_y; mb_num < mb_count; s->mb_y++) {
         ff_init_block_index(s);
-        for(; mb_num < mb_count && s->mb_x<s->mb_width; s->mb_x++){
-            const int xy= s->mb_x + s->mb_y*s->mb_stride;
+        for (; mb_num < mb_count && s->mb_x < s->mb_width; s->mb_x++) {
+            const int xy = s->mb_x + s->mb_y * s->mb_stride;
 
             mb_num++;
             ff_update_block_index(s);
-            if(s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y+1)
-                s->first_slice_line=0;
-
-            if(s->pict_type==AV_PICTURE_TYPE_I){
-                int ac_pred= get_bits1(&s->gb);
-                int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
-                if(cbpy<0){
-                    av_log(s->avctx, AV_LOG_ERROR, "cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
+            if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
+                s->first_slice_line = 0;
+
+            if (s->pict_type == AV_PICTURE_TYPE_I) {
+                int ac_pred = get_bits1(&s->gb);
+                int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
+                if (cbpy < 0) {
+                    av_log(s->avctx, AV_LOG_ERROR,
+                           "cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
                     return -1;
                 }
 
-                s->cbp_table[xy]|= cbpy<<2;
-                s->current_picture.f.mb_type[xy] |= ac_pred*MB_TYPE_ACPRED;
-            }else{ /* P || S_TYPE */
-                if (IS_INTRA(s->current_picture.f.mb_type[xy])) {
-                    int dir=0,i;
+                s->cbp_table[xy]               |= cbpy << 2;
+                s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
+            } else { /* P || S_TYPE */
+                if (IS_INTRA(s->current_picture.mb_type[xy])) {
+                    int i;
+                    int dir     = 0;
                     int ac_pred = get_bits1(&s->gb);
-                    int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
+                    int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 
-                    if(cbpy<0){
-                        av_log(s->avctx, AV_LOG_ERROR, "I cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
+                    if (cbpy < 0) {
+                        av_log(s->avctx, AV_LOG_ERROR,
+                               "I cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
                         return -1;
                     }
 
-                    if(s->cbp_table[xy] & 8) {
+                    if (s->cbp_table[xy] & 8)
                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
-                    }
-                    s->current_picture.f.qscale_table[xy] = s->qscale;
+                    s->current_picture.qscale_table[xy] = s->qscale;
 
-                    for(i=0; i<6; i++){
+                    for (i = 0; i < 6; i++) {
                         int dc_pred_dir;
-                        int dc= mpeg4_decode_dc(s, i, &dc_pred_dir);
-                        if(dc < 0){
-                            av_log(s->avctx, AV_LOG_ERROR, "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
+                        int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
+                        if (dc < 0) {
+                            av_log(s->avctx, AV_LOG_ERROR,
+                                   "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
                             return -1;
                         }
-                        dir<<=1;
-                        if(dc_pred_dir) dir|=1;
+                        dir <<= 1;
+                        if (dc_pred_dir)
+                            dir |= 1;
                     }
-                    s->cbp_table[xy]&= 3; //remove dquant
-                    s->cbp_table[xy]|= cbpy<<2;
-                    s->current_picture.f.mb_type[xy] |= ac_pred*MB_TYPE_ACPRED;
-                    s->pred_dir_table[xy]= dir;
-                } else if (IS_SKIP(s->current_picture.f.mb_type[xy])) {
-                    s->current_picture.f.qscale_table[xy] = s->qscale;
-                    s->cbp_table[xy]= 0;
-                }else{
+                    s->cbp_table[xy]               &= 3;  // remove dquant
+                    s->cbp_table[xy]               |= cbpy << 2;
+                    s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
+                    s->pred_dir_table[xy]           = dir;
+                } else if (IS_SKIP(s->current_picture.mb_type[xy])) {
+                    s->current_picture.qscale_table[xy] = s->qscale;
+                    s->cbp_table[xy]                    = 0;
+                } else {
                     int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 
-                    if(cbpy<0){
-                        av_log(s->avctx, AV_LOG_ERROR, "P cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
+                    if (cbpy < 0) {
+                        av_log(s->avctx, AV_LOG_ERROR,
+                               "P cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
                         return -1;
                     }
 
-                    if(s->cbp_table[xy] & 8) {
+                    if (s->cbp_table[xy] & 8)
                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
-                    }
-                    s->current_picture.f.qscale_table[xy] = s->qscale;
+                    s->current_picture.qscale_table[xy] = s->qscale;
 
-                    s->cbp_table[xy]&= 3; //remove dquant
-                    s->cbp_table[xy]|= (cbpy^0xf)<<2;
+                    s->cbp_table[xy] &= 3;  // remove dquant
+                    s->cbp_table[xy] |= (cbpy ^ 0xf) << 2;
                 }
             }
         }
-        if(mb_num >= mb_count) return 0;
-        s->mb_x= 0;
+        if (mb_num >= mb_count)
+            return 0;
+        s->mb_x = 0;
     }
     return 0;
 }
@@ -789,50 +865,60 @@ static int mpeg4_decode_partition_b(MpegEncContext *s, int mb_count){
  * Decode the first and second partition.
  * @return <0 if error (and sets error type in the error_status_table)
  */
-int ff_mpeg4_decode_partitions(MpegEncContext *s)
+int ff_mpeg4_decode_partitions(Mpeg4DecContext *ctx)
 {
+    MpegEncContext *s = &ctx->m;
     int mb_num;
-    const int part_a_error= s->pict_type==AV_PICTURE_TYPE_I ? (ER_DC_ERROR|ER_MV_ERROR) : ER_MV_ERROR;
-    const int part_a_end  = s->pict_type==AV_PICTURE_TYPE_I ? (ER_DC_END  |ER_MV_END)   : ER_MV_END;
+    const int part_a_error = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_ERROR | ER_MV_ERROR) : ER_MV_ERROR;
+    const int part_a_end   = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_END   | ER_MV_END)   : ER_MV_END;
 
-    mb_num= mpeg4_decode_partition_a(s);
-    if(mb_num<0){
-        ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, part_a_error);
+    mb_num = mpeg4_decode_partition_a(ctx);
+    if (mb_num < 0) {
+        ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
+                        s->mb_x, s->mb_y, part_a_error);
         return -1;
     }
 
-    if(s->resync_mb_x + s->resync_mb_y*s->mb_width + mb_num > s->mb_num){
+    if (s->resync_mb_x + s->resync_mb_y * s->mb_width + mb_num > s->mb_num) {
         av_log(s->avctx, AV_LOG_ERROR, "slice below monitor ...\n");
-        ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, part_a_error);
+        ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
+                        s->mb_x, s->mb_y, part_a_error);
         return -1;
     }
 
-    s->mb_num_left= mb_num;
+    s->mb_num_left = mb_num;
 
-    if(s->pict_type==AV_PICTURE_TYPE_I){
-        while(show_bits(&s->gb, 9) == 1)
+    if (s->pict_type == AV_PICTURE_TYPE_I) {
+        while (show_bits(&s->gb, 9) == 1)
             skip_bits(&s->gb, 9);
-        if(get_bits_long(&s->gb, 19)!=DC_MARKER){
-            av_log(s->avctx, AV_LOG_ERROR, "marker missing after first I partition at %d %d\n", s->mb_x, s->mb_y);
+        if (get_bits_long(&s->gb, 19) != DC_MARKER) {
+            av_log(s->avctx, AV_LOG_ERROR,
+                   "marker missing after first I partition at %d %d\n",
+                   s->mb_x, s->mb_y);
             return -1;
         }
-    }else{
-        while(show_bits(&s->gb, 10) == 1)
+    } else {
+        while (show_bits(&s->gb, 10) == 1)
             skip_bits(&s->gb, 10);
-        if(get_bits(&s->gb, 17)!=MOTION_MARKER){
-            av_log(s->avctx, AV_LOG_ERROR, "marker missing after first P partition at %d %d\n", s->mb_x, s->mb_y);
+        if (get_bits(&s->gb, 17) != MOTION_MARKER) {
+            av_log(s->avctx, AV_LOG_ERROR,
+                   "marker missing after first P partition at %d %d\n",
+                   s->mb_x, s->mb_y);
             return -1;
         }
     }
-    ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, part_a_end);
+    ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
+                    s->mb_x - 1, s->mb_y, part_a_end);
 
-    if( mpeg4_decode_partition_b(s, mb_num) < 0){
-        if(s->pict_type==AV_PICTURE_TYPE_P)
-            ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_DC_ERROR);
+    if (mpeg4_decode_partition_b(s, mb_num) < 0) {
+        if (s->pict_type == AV_PICTURE_TYPE_P)
+            ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
+                            s->mb_x, s->mb_y, ER_DC_ERROR);
         return -1;
-    }else{
-        if(s->pict_type==AV_PICTURE_TYPE_P)
-            ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_DC_END);
+    } else {
+        if (s->pict_type == AV_PICTURE_TYPE_P)
+            ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
+                            s->mb_x - 1, s->mb_y, ER_DC_END);
     }
 
     return 0;
@@ -842,221 +928,242 @@ int ff_mpeg4_decode_partitions(MpegEncContext *s)
  * Decode a block.
  * @return <0 if an error occurred
  */
-static inline int mpeg4_decode_block(MpegEncContext * s, int16_t * block,
-                              int n, int coded, int intra, int rvlc)
+static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
+                                     int n, int coded, int intra, int rvlc)
 {
-    int level, i, last, run;
-    int dc_pred_dir;
-    RLTable * rl;
-    RL_VLC_ELEM * rl_vlc;
-    const uint8_t * scan_table;
-    int qmul, qadd;
-
-    //Note intra & rvlc should be optimized away if this is inlined
-
-    if(intra) {
-      if(s->use_intra_dc_vlc){
-        /* DC coef */
-        if(s->partitioned_frame){
-            level = s->dc_val[0][ s->block_index[n] ];
-            if(n<4) level= FASTDIV((level + (s->y_dc_scale>>1)), s->y_dc_scale);
-            else    level= FASTDIV((level + (s->c_dc_scale>>1)), s->c_dc_scale);
-            dc_pred_dir= (s->pred_dir_table[s->mb_x + s->mb_y*s->mb_stride]<<n)&32;
-        }else{
-            level = mpeg4_decode_dc(s, n, &dc_pred_dir);
-            if (level < 0)
-                return -1;
-        }
-        block[0] = level;
-        i = 0;
-      }else{
+    MpegEncContext *s = &ctx->m;
+    int level, i, last, run, qmul, qadd, dc_pred_dir;
+    RLTable *rl;
+    RL_VLC_ELEM *rl_vlc;
+    const uint8_t *scan_table;
+
+    // Note intra & rvlc should be optimized away if this is inlined
+
+    if (intra) {
+        if (ctx->use_intra_dc_vlc) {
+            /* DC coef */
+            if (s->partitioned_frame) {
+                level = s->dc_val[0][s->block_index[n]];
+                if (n < 4)
+                    level = FASTDIV((level + (s->y_dc_scale >> 1)), s->y_dc_scale);
+                else
+                    level = FASTDIV((level + (s->c_dc_scale >> 1)), s->c_dc_scale);
+                dc_pred_dir = (s->pred_dir_table[s->mb_x + s->mb_y * s->mb_stride] << n) & 32;
+            } else {
+                level = mpeg4_decode_dc(s, n, &dc_pred_dir);
+                if (level < 0)
+                    return -1;
+            }
+            block[0] = level;
+            i        = 0;
+        } else {
             i = -1;
             ff_mpeg4_pred_dc(s, n, 0, &dc_pred_dir, 0);
-      }
-      if (!coded)
-          goto not_coded;
-
-      if(rvlc){
-          rl = &ff_rvlc_rl_intra;
-          rl_vlc = ff_rvlc_rl_intra.rl_vlc[0];
-      }else{
-          rl = &ff_mpeg4_rl_intra;
-          rl_vlc = ff_mpeg4_rl_intra.rl_vlc[0];
-      }
-      if (s->ac_pred) {
-          if (dc_pred_dir == 0)
-              scan_table = s->intra_v_scantable.permutated; /* left */
-          else
-              scan_table = s->intra_h_scantable.permutated; /* top */
-      } else {
+        }
+        if (!coded)
+            goto not_coded;
+
+        if (rvlc) {
+            rl     = &ff_rvlc_rl_intra;
+            rl_vlc = ff_rvlc_rl_intra.rl_vlc[0];
+        } else {
+            rl     = &ff_mpeg4_rl_intra;
+            rl_vlc = ff_mpeg4_rl_intra.rl_vlc[0];
+        }
+        if (s->ac_pred) {
+            if (dc_pred_dir == 0)
+                scan_table = s->intra_v_scantable.permutated;  /* left */
+            else
+                scan_table = s->intra_h_scantable.permutated;  /* top */
+        } else {
             scan_table = s->intra_scantable.permutated;
-      }
-      qmul=1;
-      qadd=0;
+        }
+        qmul = 1;
+        qadd = 0;
     } else {
         i = -1;
         if (!coded) {
             s->block_last_index[n] = i;
             return 0;
         }
-        if(rvlc) rl = &ff_rvlc_rl_inter;
-        else     rl = &ff_h263_rl_inter;
+        if (rvlc)
+            rl = &ff_rvlc_rl_inter;
+        else
+            rl = &ff_h263_rl_inter;
 
         scan_table = s->intra_scantable.permutated;
 
-        if(s->mpeg_quant){
-            qmul=1;
-            qadd=0;
-            if(rvlc){
+        if (s->mpeg_quant) {
+            qmul = 1;
+            qadd = 0;
+            if (rvlc)
                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[0];
-            }else{
+            else
                 rl_vlc = ff_h263_rl_inter.rl_vlc[0];
-            }
-        }else{
+        } else {
             qmul = s->qscale << 1;
             qadd = (s->qscale - 1) | 1;
-            if(rvlc){
+            if (rvlc)
                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[s->qscale];
-            }else{
+            else
                 rl_vlc = ff_h263_rl_inter.rl_vlc[s->qscale];
-            }
         }
     }
-  {
-    OPEN_READER(re, &s->gb);
-    for(;;) {
-        UPDATE_CACHE(re, &s->gb);
-        GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
-        if (level==0) {
-          /* escape */
-          if(rvlc){
-                if(SHOW_UBITS(re, &s->gb, 1)==0){
-                    av_log(s->avctx, AV_LOG_ERROR, "1. marker bit missing in rvlc esc\n");
-                    return -1;
-                }; SKIP_CACHE(re, &s->gb, 1);
-
-                last=  SHOW_UBITS(re, &s->gb, 1); SKIP_CACHE(re, &s->gb, 1);
-                run=   SHOW_UBITS(re, &s->gb, 6);
-                SKIP_COUNTER(re, &s->gb, 1+1+6);
-                UPDATE_CACHE(re, &s->gb);
-
-                if(SHOW_UBITS(re, &s->gb, 1)==0){
-                    av_log(s->avctx, AV_LOG_ERROR, "2. marker bit missing in rvlc esc\n");
-                    return -1;
-                }; SKIP_CACHE(re, &s->gb, 1);
-
-                level= SHOW_UBITS(re, &s->gb, 11); SKIP_CACHE(re, &s->gb, 11);
-
-                if(SHOW_UBITS(re, &s->gb, 5)!=0x10){
-                    av_log(s->avctx, AV_LOG_ERROR, "reverse esc missing\n");
-                    return -1;
-                }; SKIP_CACHE(re, &s->gb, 5);
+    {
+        OPEN_READER(re, &s->gb);
+        for (;;) {
+            UPDATE_CACHE(re, &s->gb);
+            GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
+            if (level == 0) {
+                /* escape */
+                if (rvlc) {
+                    if (SHOW_UBITS(re, &s->gb, 1) == 0) {
+                        av_log(s->avctx, AV_LOG_ERROR,
+                               "1. marker bit missing in rvlc esc\n");
+                        return -1;
+                    }
+                    SKIP_CACHE(re, &s->gb, 1);
 
-                level=  level * qmul + qadd;
-                level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
-                SKIP_COUNTER(re, &s->gb, 1+11+5+1);
-
-                i+= run + 1;
-                if(last) i+=192;
-          }else{
-            int cache;
-            cache= GET_CACHE(re, &s->gb);
-
-            if(IS_3IV1)
-                cache ^= 0xC0000000;
-
-            if (cache&0x80000000) {
-                if (cache&0x40000000) {
-                    /* third escape */
-                    SKIP_CACHE(re, &s->gb, 2);
-                    last=  SHOW_UBITS(re, &s->gb, 1); SKIP_CACHE(re, &s->gb, 1);
-                    run=   SHOW_UBITS(re, &s->gb, 6);
-                    SKIP_COUNTER(re, &s->gb, 2+1+6);
+                    last = SHOW_UBITS(re, &s->gb, 1);
+                    SKIP_CACHE(re, &s->gb, 1);
+                    run = SHOW_UBITS(re, &s->gb, 6);
+                    SKIP_COUNTER(re, &s->gb, 1 + 1 + 6);
                     UPDATE_CACHE(re, &s->gb);
 
-                    if(IS_3IV1){
-                        level= SHOW_SBITS(re, &s->gb, 12); LAST_SKIP_BITS(re, &s->gb, 12);
-                    }else{
-                        if(SHOW_UBITS(re, &s->gb, 1)==0){
-                            av_log(s->avctx, AV_LOG_ERROR, "1. marker bit missing in 3. esc\n");
-                            return -1;
-                        }; SKIP_CACHE(re, &s->gb, 1);
-
-                        level= SHOW_SBITS(re, &s->gb, 12); SKIP_CACHE(re, &s->gb, 12);
+                    if (SHOW_UBITS(re, &s->gb, 1) == 0) {
+                        av_log(s->avctx, AV_LOG_ERROR,
+                               "2. marker bit missing in rvlc esc\n");
+                        return -1;
+                    }
+                    SKIP_CACHE(re, &s->gb, 1);
 
-                        if(SHOW_UBITS(re, &s->gb, 1)==0){
-                            av_log(s->avctx, AV_LOG_ERROR, "2. marker bit missing in 3. esc\n");
-                            return -1;
-                        }
+                    level = SHOW_UBITS(re, &s->gb, 11);
+                    SKIP_CACHE(re, &s->gb, 11);
 
-                        SKIP_COUNTER(re, &s->gb, 1+12+1);
+                    if (SHOW_UBITS(re, &s->gb, 5) != 0x10) {
+                        av_log(s->avctx, AV_LOG_ERROR, "reverse esc missing\n");
+                        return -1;
                     }
+                    SKIP_CACHE(re, &s->gb, 5);
 
-                    if (level>0) level= level * qmul + qadd;
-                    else         level= level * qmul - qadd;
+                    level = level * qmul + qadd;
+                    level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
+                    SKIP_COUNTER(re, &s->gb, 1 + 11 + 5 + 1);
 
-                    if((unsigned)(level + 2048) > 4095){
-                        if(s->err_recognition & AV_EF_BITSTREAM){
-                            if(level > 2560 || level<-2560){
-                                av_log(s->avctx, AV_LOG_ERROR, "|level| overflow in 3. esc, qp=%d\n", s->qscale);
-                                return -1;
+                    i += run + 1;
+                    if (last)
+                        i += 192;
+                } else {
+                    int cache;
+                    cache = GET_CACHE(re, &s->gb);
+
+                    if (IS_3IV1)
+                        cache ^= 0xC0000000;
+
+                    if (cache & 0x80000000) {
+                        if (cache & 0x40000000) {
+                            /* third escape */
+                            SKIP_CACHE(re, &s->gb, 2);
+                            last = SHOW_UBITS(re, &s->gb, 1);
+                            SKIP_CACHE(re, &s->gb, 1);
+                            run = SHOW_UBITS(re, &s->gb, 6);
+                            SKIP_COUNTER(re, &s->gb, 2 + 1 + 6);
+                            UPDATE_CACHE(re, &s->gb);
+
+                            if (IS_3IV1) {
+                                level = SHOW_SBITS(re, &s->gb, 12);
+                                LAST_SKIP_BITS(re, &s->gb, 12);
+                            } else {
+                                if (SHOW_UBITS(re, &s->gb, 1) == 0) {
+                                    av_log(s->avctx, AV_LOG_ERROR,
+                                           "1. marker bit missing in 3. esc\n");
+                                    return -1;
+                                }
+                                SKIP_CACHE(re, &s->gb, 1);
+
+                                level = SHOW_SBITS(re, &s->gb, 12);
+                                SKIP_CACHE(re, &s->gb, 12);
+
+                                if (SHOW_UBITS(re, &s->gb, 1) == 0) {
+                                    av_log(s->avctx, AV_LOG_ERROR,
+                                           "2. marker bit missing in 3. esc\n");
+                                    return -1;
+                                }
+
+                                SKIP_COUNTER(re, &s->gb, 1 + 12 + 1);
                             }
+
+                            if (level > 0)
+                                level = level * qmul + qadd;
+                            else
+                                level = level * qmul - qadd;
+
+                            if ((unsigned)(level + 2048) > 4095) {
+                                if (s->err_recognition & AV_EF_BITSTREAM) {
+                                    if (level > 2560 || level < -2560) {
+                                        av_log(s->avctx, AV_LOG_ERROR,
+                                               "|level| overflow in 3. esc, qp=%d\n",
+                                               s->qscale);
+                                        return -1;
+                                    }
+                                }
+                                level = level < 0 ? -2048 : 2047;
+                            }
+
+                            i += run + 1;
+                            if (last)
+                                i += 192;
+                        } else {
+                            /* second escape */
+                            SKIP_BITS(re, &s->gb, 2);
+                            GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
+                            i    += run + rl->max_run[run >> 7][level / qmul] + 1;  // FIXME opt indexing
+                            level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
+                            LAST_SKIP_BITS(re, &s->gb, 1);
                         }
-                        level= level<0 ? -2048 : 2047;
+                    } else {
+                        /* first escape */
+                        SKIP_BITS(re, &s->gb, 1);
+                        GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
+                        i    += run;
+                        level = level + rl->max_level[run >> 7][(run - 1) & 63] * qmul;  // FIXME opt indexing
+                        level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
+                        LAST_SKIP_BITS(re, &s->gb, 1);
                     }
-
-                    i+= run + 1;
-                    if(last) i+=192;
-                } else {
-                    /* second escape */
-                    SKIP_BITS(re, &s->gb, 2);
-                    GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
-                    i+= run + rl->max_run[run>>7][level/qmul] +1; //FIXME opt indexing
-                    level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
-                    LAST_SKIP_BITS(re, &s->gb, 1);
                 }
             } else {
-                /* first escape */
-                SKIP_BITS(re, &s->gb, 1);
-                GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
-                i+= run;
-                level = level + rl->max_level[run>>7][(run-1)&63] * qmul;//FIXME opt indexing
+                i    += run;
                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
                 LAST_SKIP_BITS(re, &s->gb, 1);
             }
-          }
-        } else {
-            i+= run;
-            level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
-            LAST_SKIP_BITS(re, &s->gb, 1);
-        }
-        if (i > 62){
-            i-= 192;
-            if(i&(~63)){
-                av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
-                return -1;
+            if (i > 62) {
+                i -= 192;
+                if (i & (~63)) {
+                    av_log(s->avctx, AV_LOG_ERROR,
+                           "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
+                    return -1;
+                }
+
+                block[scan_table[i]] = level;
+                break;
             }
 
             block[scan_table[i]] = level;
-            break;
         }
-
-        block[scan_table[i]] = level;
+        CLOSE_READER(re, &s->gb);
     }
-    CLOSE_READER(re, &s->gb);
-  }
- not_coded:
+
+not_coded:
     if (intra) {
-        if(!s->use_intra_dc_vlc){
+        if (!ctx->use_intra_dc_vlc) {
             block[0] = ff_mpeg4_pred_dc(s, n, block[0], &dc_pred_dir, 0);
 
-            i -= i>>31; //if(i == -1) i=0;
+            i -= i >> 31;  // if (i == -1) i = 0;
         }
 
         ff_mpeg4_pred_ac(s, block, n, dc_pred_dir);
-        if (s->ac_pred) {
-            i = 63; /* XXX: not optimal */
-        }
+        if (s->ac_pred)
+            i = 63;  // FIXME not optimal
     }
     s->block_last_index[n] = i;
     return 0;
@@ -1068,43 +1175,45 @@ static inline int mpeg4_decode_block(MpegEncContext * s, int16_t * block,
  */
 static int mpeg4_decode_partitioned_mb(MpegEncContext *s, int16_t block[6][64])
 {
+    Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
     int cbp, mb_type;
-    const int xy= s->mb_x + s->mb_y*s->mb_stride;
+    const int xy = s->mb_x + s->mb_y * s->mb_stride;
 
-    mb_type = s->current_picture.f.mb_type[xy];
-    cbp = s->cbp_table[xy];
+    mb_type = s->current_picture.mb_type[xy];
+    cbp     = s->cbp_table[xy];
 
-    s->use_intra_dc_vlc= s->qscale < s->intra_dc_threshold;
+    ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
 
-    if (s->current_picture.f.qscale_table[xy] != s->qscale) {
-        ff_set_qscale(s, s->current_picture.f.qscale_table[xy]);
-    }
+    if (s->current_picture.qscale_table[xy] != s->qscale)
+        ff_set_qscale(s, s->current_picture.qscale_table[xy]);
 
-    if (s->pict_type == AV_PICTURE_TYPE_P || s->pict_type==AV_PICTURE_TYPE_S) {
+    if (s->pict_type == AV_PICTURE_TYPE_P ||
+        s->pict_type == AV_PICTURE_TYPE_S) {
         int i;
-        for(i=0; i<4; i++){
-            s->mv[0][i][0] = s->current_picture.f.motion_val[0][s->block_index[i]][0];
-            s->mv[0][i][1] = s->current_picture.f.motion_val[0][s->block_index[i]][1];
+        for (i = 0; i < 4; i++) {
+            s->mv[0][i][0] = s->current_picture.motion_val[0][s->block_index[i]][0];
+            s->mv[0][i][1] = s->current_picture.motion_val[0][s->block_index[i]][1];
         }
         s->mb_intra = IS_INTRA(mb_type);
 
         if (IS_SKIP(mb_type)) {
             /* skip mb */
-            for(i=0;i<6;i++)
+            for (i = 0; i < 6; i++)
                 s->block_last_index[i] = -1;
-            s->mv_dir = MV_DIR_FORWARD;
+            s->mv_dir  = MV_DIR_FORWARD;
             s->mv_type = MV_TYPE_16X16;
-            if(s->pict_type==AV_PICTURE_TYPE_S && s->vol_sprite_usage==GMC_SPRITE){
-                s->mcsel=1;
+            if (s->pict_type == AV_PICTURE_TYPE_S
+                && ctx->vol_sprite_usage == GMC_SPRITE) {
+                s->mcsel      = 1;
                 s->mb_skipped = 0;
-            }else{
-                s->mcsel=0;
+            } else {
+                s->mcsel      = 0;
                 s->mb_skipped = 1;
             }
-        }else if(s->mb_intra){
-            s->ac_pred = IS_ACPRED(s->current_picture.f.mb_type[xy]);
-        }else if(!s->mb_intra){
-//            s->mcsel= 0; //FIXME do we need to init that
+        } else if (s->mb_intra) {
+            s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
+        } else if (!s->mb_intra) {
+            // s->mcsel = 0;  // FIXME do we need to init that?
 
             s->mv_dir = MV_DIR_FORWARD;
             if (IS_8X8(mb_type)) {
@@ -1115,132 +1224,147 @@ static int mpeg4_decode_partitioned_mb(MpegEncContext *s, int16_t block[6][64])
         }
     } else { /* I-Frame */
         s->mb_intra = 1;
-        s->ac_pred = IS_ACPRED(s->current_picture.f.mb_type[xy]);
+        s->ac_pred  = IS_ACPRED(s->current_picture.mb_type[xy]);
     }
 
     if (!IS_SKIP(mb_type)) {
         int i;
-        s->dsp.clear_blocks(s->block[0]);
+        s->bdsp.clear_blocks(s->block[0]);
         /* decode each block */
         for (i = 0; i < 6; i++) {
-            if(mpeg4_decode_block(s, block[i], i, cbp&32, s->mb_intra, s->rvlc) < 0){
-                av_log(s->avctx, AV_LOG_ERROR, "texture corrupted at %d %d %d\n", s->mb_x, s->mb_y, s->mb_intra);
+            if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, s->mb_intra, ctx->rvlc) < 0) {
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "texture corrupted at %d %d %d\n",
+                       s->mb_x, s->mb_y, s->mb_intra);
                 return -1;
             }
-            cbp+=cbp;
+            cbp += cbp;
         }
     }
 
     /* per-MB end of slice check */
-
-    if(--s->mb_num_left <= 0){
-        if(mpeg4_is_resync(s))
+    if (--s->mb_num_left <= 0) {
+        if (mpeg4_is_resync(s))
             return SLICE_END;
         else
             return SLICE_NOEND;
-    }else{
-        if(mpeg4_is_resync(s)){
-            const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
-            if(s->cbp_table[xy+delta])
+    } else {
+        if (mpeg4_is_resync(s)) {
+            const int delta = s->mb_x + 1 == s->mb_width ? 2 : 1;
+            if (s->cbp_table[xy + delta])
                 return SLICE_END;
         }
         return SLICE_OK;
     }
 }
 
-static int mpeg4_decode_mb(MpegEncContext *s,
-                      int16_t block[6][64])
+static int mpeg4_decode_mb(MpegEncContext *s, int16_t block[6][64])
 {
+    Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
     int16_t *mot_val;
     static int8_t quant_tab[4] = { -1, -2, 1, 2 };
-    const int xy= s->mb_x + s->mb_y * s->mb_stride;
+    const int xy = s->mb_x + s->mb_y * s->mb_stride;
 
     assert(s->h263_pred);
 
-    if (s->pict_type == AV_PICTURE_TYPE_P || s->pict_type==AV_PICTURE_TYPE_S) {
-        do{
+    if (s->pict_type == AV_PICTURE_TYPE_P ||
+        s->pict_type == AV_PICTURE_TYPE_S) {
+        do {
             if (get_bits1(&s->gb)) {
                 /* skip mb */
                 s->mb_intra = 0;
-                for(i=0;i<6;i++)
+                for (i = 0; i < 6; i++)
                     s->block_last_index[i] = -1;
-                s->mv_dir = MV_DIR_FORWARD;
+                s->mv_dir  = MV_DIR_FORWARD;
                 s->mv_type = MV_TYPE_16X16;
-                if(s->pict_type==AV_PICTURE_TYPE_S && s->vol_sprite_usage==GMC_SPRITE){
-                    s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_GMC | MB_TYPE_16x16 | MB_TYPE_L0;
-                    s->mcsel=1;
-                    s->mv[0][0][0]= get_amv(s, 0);
-                    s->mv[0][0][1]= get_amv(s, 1);
-
-                    s->mb_skipped = 0;
-                }else{
-                    s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
-                    s->mcsel=0;
+                if (s->pict_type == AV_PICTURE_TYPE_S &&
+                    ctx->vol_sprite_usage == GMC_SPRITE) {
+                    s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
+                                                     MB_TYPE_GMC   |
+                                                     MB_TYPE_16x16 |
+                                                     MB_TYPE_L0;
+                    s->mcsel       = 1;
+                    s->mv[0][0][0] = get_amv(ctx, 0);
+                    s->mv[0][0][1] = get_amv(ctx, 1);
+                    s->mb_skipped  = 0;
+                } else {
+                    s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
+                                                     MB_TYPE_16x16 |
+                                                     MB_TYPE_L0;
+                    s->mcsel       = 0;
                     s->mv[0][0][0] = 0;
                     s->mv[0][0][1] = 0;
-                    s->mb_skipped = 1;
+                    s->mb_skipped  = 1;
                 }
                 goto end;
             }
             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
-            if (cbpc < 0){
-                av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
+            if (cbpc < 0) {
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
                 return -1;
             }
-        }while(cbpc == 20);
+        } while (cbpc == 20);
 
-        s->dsp.clear_blocks(s->block[0]);
-        dquant = cbpc & 8;
+        s->bdsp.clear_blocks(s->block[0]);
+        dquant      = cbpc & 8;
         s->mb_intra = ((cbpc & 4) != 0);
-        if (s->mb_intra) goto intra;
+        if (s->mb_intra)
+            goto intra;
 
-        if(s->pict_type==AV_PICTURE_TYPE_S && s->vol_sprite_usage==GMC_SPRITE && (cbpc & 16) == 0)
-            s->mcsel= get_bits1(&s->gb);
-        else s->mcsel= 0;
+        if (s->pict_type == AV_PICTURE_TYPE_S &&
+            ctx->vol_sprite_usage == GMC_SPRITE && (cbpc & 16) == 0)
+            s->mcsel = get_bits1(&s->gb);
+        else
+            s->mcsel = 0;
         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1) ^ 0x0F;
 
         cbp = (cbpc & 3) | (cbpy << 2);
-        if (dquant) {
+        if (dquant)
             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
-        }
-        if((!s->progressive_sequence) && (cbp || (s->workaround_bugs&FF_BUG_XVID_ILACE)))
-            s->interlaced_dct= get_bits1(&s->gb);
+        if ((!s->progressive_sequence) &&
+            (cbp || (s->workaround_bugs & FF_BUG_XVID_ILACE)))
+            s->interlaced_dct = get_bits1(&s->gb);
 
         s->mv_dir = MV_DIR_FORWARD;
         if ((cbpc & 16) == 0) {
-            if(s->mcsel){
-                s->current_picture.f.mb_type[xy] = MB_TYPE_GMC | MB_TYPE_16x16 | MB_TYPE_L0;
+            if (s->mcsel) {
+                s->current_picture.mb_type[xy] = MB_TYPE_GMC   |
+                                                 MB_TYPE_16x16 |
+                                                 MB_TYPE_L0;
                 /* 16x16 global motion prediction */
-                s->mv_type = MV_TYPE_16X16;
-                mx= get_amv(s, 0);
-                my= get_amv(s, 1);
+                s->mv_type     = MV_TYPE_16X16;
+                mx             = get_amv(ctx, 0);
+                my             = get_amv(ctx, 1);
                 s->mv[0][0][0] = mx;
                 s->mv[0][0][1] = my;
-            }else if((!s->progressive_sequence) && get_bits1(&s->gb)){
-                s->current_picture.f.mb_type[xy] = MB_TYPE_16x8 | MB_TYPE_L0 | MB_TYPE_INTERLACED;
+            } else if ((!s->progressive_sequence) && get_bits1(&s->gb)) {
+                s->current_picture.mb_type[xy] = MB_TYPE_16x8 |
+                                                 MB_TYPE_L0   |
+                                                 MB_TYPE_INTERLACED;
                 /* 16x8 field motion prediction */
-                s->mv_type= MV_TYPE_FIELD;
+                s->mv_type = MV_TYPE_FIELD;
 
-                s->field_select[0][0]= get_bits1(&s->gb);
-                s->field_select[0][1]= get_bits1(&s->gb);
+                s->field_select[0][0] = get_bits1(&s->gb);
+                s->field_select[0][1] = get_bits1(&s->gb);
 
                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 
-                for(i=0; i<2; i++){
+                for (i = 0; i < 2; i++) {
                     mx = ff_h263_decode_motion(s, pred_x, s->f_code);
                     if (mx >= 0xffff)
                         return -1;
 
-                    my = ff_h263_decode_motion(s, pred_y/2, s->f_code);
+                    my = ff_h263_decode_motion(s, pred_y / 2, s->f_code);
                     if (my >= 0xffff)
                         return -1;
 
                     s->mv[0][i][0] = mx;
                     s->mv[0][i][1] = my;
                 }
-            }else{
-                s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
+            } else {
+                s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
                 /* 16x16 motion prediction */
                 s->mv_type = MV_TYPE_16X16;
                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
@@ -1257,11 +1381,11 @@ static int mpeg4_decode_mb(MpegEncContext *s,
                 s->mv[0][0][1] = my;
             }
         } else {
-            s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
-            s->mv_type = MV_TYPE_8X8;
-            for(i=0;i<4;i++) {
+            s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
+            s->mv_type                     = MV_TYPE_8X8;
+            for (i = 0; i < 4; i++) {
                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
-                mx = ff_h263_decode_motion(s, pred_x, s->f_code);
+                mx      = ff_h263_decode_motion(s, pred_x, s->f_code);
                 if (mx >= 0xffff)
                     return -1;
 
@@ -1270,213 +1394,233 @@ static int mpeg4_decode_mb(MpegEncContext *s,
                     return -1;
                 s->mv[0][i][0] = mx;
                 s->mv[0][i][1] = my;
-                mot_val[0] = mx;
-                mot_val[1] = my;
+                mot_val[0]     = mx;
+                mot_val[1]     = my;
             }
         }
-    } else if(s->pict_type==AV_PICTURE_TYPE_B) {
-        int modb1; // first bit of modb
-        int modb2; // second bit of modb
+    } else if (s->pict_type == AV_PICTURE_TYPE_B) {
+        int modb1;   // first bit of modb
+        int modb2;   // second bit of modb
         int mb_type;
 
-        s->mb_intra = 0; //B-frames never contain intra blocks
-        s->mcsel=0;      //     ...               true gmc blocks
+        s->mb_intra = 0;  // B-frames never contain intra blocks
+        s->mcsel    = 0;  //      ...               true gmc blocks
 
-        if(s->mb_x==0){
-            for(i=0; i<2; i++){
-                s->last_mv[i][0][0]=
-                s->last_mv[i][0][1]=
-                s->last_mv[i][1][0]=
-                s->last_mv[i][1][1]= 0;
+        if (s->mb_x == 0) {
+            for (i = 0; i < 2; i++) {
+                s->last_mv[i][0][0] =
+                s->last_mv[i][0][1] =
+                s->last_mv[i][1][0] =
+                s->last_mv[i][1][1] = 0;
             }
 
-            ff_thread_await_progress(&s->next_picture_ptr->f, s->mb_y, 0);
+            ff_thread_await_progress(&s->next_picture_ptr->tf, s->mb_y, 0);
         }
 
         /* if we skipped it in the future P Frame than skip it now too */
-        s->mb_skipped = s->next_picture.f.mbskip_table[s->mb_y * s->mb_stride + s->mb_x]; // Note, skiptab=0 if last was GMC
+        s->mb_skipped = s->next_picture.mbskip_table[s->mb_y * s->mb_stride + s->mb_x];  // Note, skiptab=0 if last was GMC
 
-        if(s->mb_skipped){
-                /* skip mb */
-            for(i=0;i<6;i++)
+        if (s->mb_skipped) {
+            /* skip mb */
+            for (i = 0; i < 6; i++)
                 s->block_last_index[i] = -1;
 
-            s->mv_dir = MV_DIR_FORWARD;
-            s->mv_type = MV_TYPE_16X16;
-            s->mv[0][0][0] = 0;
-            s->mv[0][0][1] = 0;
-            s->mv[1][0][0] = 0;
+            s->mv_dir      = MV_DIR_FORWARD;
+            s->mv_type     = MV_TYPE_16X16;
+            s->mv[0][0][0] =
+            s->mv[0][0][1] =
+            s->mv[1][0][0] =
             s->mv[1][0][1] = 0;
-            s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
+            s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
+                                             MB_TYPE_16x16 |
+                                             MB_TYPE_L0;
             goto end;
         }
 
-        modb1= get_bits1(&s->gb);
-        if(modb1){
-            mb_type= MB_TYPE_DIRECT2 | MB_TYPE_SKIP | MB_TYPE_L0L1; //like MB_TYPE_B_DIRECT but no vectors coded
-            cbp=0;
-        }else{
-            modb2= get_bits1(&s->gb);
-            mb_type= get_vlc2(&s->gb, mb_type_b_vlc.table, MB_TYPE_B_VLC_BITS, 1);
-            if(mb_type<0){
+        modb1 = get_bits1(&s->gb);
+        if (modb1) {
+            // like MB_TYPE_B_DIRECT but no vectors coded
+            mb_type = MB_TYPE_DIRECT2 | MB_TYPE_SKIP | MB_TYPE_L0L1;
+            cbp     = 0;
+        } else {
+            modb2   = get_bits1(&s->gb);
+            mb_type = get_vlc2(&s->gb, mb_type_b_vlc.table, MB_TYPE_B_VLC_BITS, 1);
+            if (mb_type < 0) {
                 av_log(s->avctx, AV_LOG_ERROR, "illegal MB_type\n");
                 return -1;
             }
-            mb_type= mb_type_b_map[ mb_type ];
-            if(modb2) cbp= 0;
-            else{
-                s->dsp.clear_blocks(s->block[0]);
-                cbp= get_bits(&s->gb, 6);
+            mb_type = mb_type_b_map[mb_type];
+            if (modb2) {
+                cbp = 0;
+            } else {
+                s->bdsp.clear_blocks(s->block[0]);
+                cbp = get_bits(&s->gb, 6);
             }
 
             if ((!IS_DIRECT(mb_type)) && cbp) {
-                if(get_bits1(&s->gb)){
-                    ff_set_qscale(s, s->qscale + get_bits1(&s->gb)*4 - 2);
-                }
+                if (get_bits1(&s->gb))
+                    ff_set_qscale(s, s->qscale + get_bits1(&s->gb) * 4 - 2);
             }
 
-            if(!s->progressive_sequence){
-                if(cbp)
-                    s->interlaced_dct= get_bits1(&s->gb);
+            if (!s->progressive_sequence) {
+                if (cbp)
+                    s->interlaced_dct = get_bits1(&s->gb);
 
-                if(!IS_DIRECT(mb_type) && get_bits1(&s->gb)){
+                if (!IS_DIRECT(mb_type) && get_bits1(&s->gb)) {
                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
                     mb_type &= ~MB_TYPE_16x16;
 
-                    if(USES_LIST(mb_type, 0)){
-                        s->field_select[0][0]= get_bits1(&s->gb);
-                        s->field_select[0][1]= get_bits1(&s->gb);
+                    if (USES_LIST(mb_type, 0)) {
+                        s->field_select[0][0] = get_bits1(&s->gb);
+                        s->field_select[0][1] = get_bits1(&s->gb);
                     }
-                    if(USES_LIST(mb_type, 1)){
-                        s->field_select[1][0]= get_bits1(&s->gb);
-                        s->field_select[1][1]= get_bits1(&s->gb);
+                    if (USES_LIST(mb_type, 1)) {
+                        s->field_select[1][0] = get_bits1(&s->gb);
+                        s->field_select[1][1] = get_bits1(&s->gb);
                     }
                 }
             }
 
             s->mv_dir = 0;
-            if((mb_type & (MB_TYPE_DIRECT2|MB_TYPE_INTERLACED)) == 0){
-                s->mv_type= MV_TYPE_16X16;
+            if ((mb_type & (MB_TYPE_DIRECT2 | MB_TYPE_INTERLACED)) == 0) {
+                s->mv_type = MV_TYPE_16X16;
 
-                if(USES_LIST(mb_type, 0)){
+                if (USES_LIST(mb_type, 0)) {
                     s->mv_dir = MV_DIR_FORWARD;
 
                     mx = ff_h263_decode_motion(s, s->last_mv[0][0][0], s->f_code);
                     my = ff_h263_decode_motion(s, s->last_mv[0][0][1], s->f_code);
-                    s->last_mv[0][1][0]= s->last_mv[0][0][0]= s->mv[0][0][0] = mx;
-                    s->last_mv[0][1][1]= s->last_mv[0][0][1]= s->mv[0][0][1] = my;
+                    s->last_mv[0][1][0] =
+                    s->last_mv[0][0][0] =
+                    s->mv[0][0][0]      = mx;
+                    s->last_mv[0][1][1] =
+                    s->last_mv[0][0][1] =
+                    s->mv[0][0][1]      = my;
                 }
 
-                if(USES_LIST(mb_type, 1)){
+                if (USES_LIST(mb_type, 1)) {
                     s->mv_dir |= MV_DIR_BACKWARD;
 
                     mx = ff_h263_decode_motion(s, s->last_mv[1][0][0], s->b_code);
                     my = ff_h263_decode_motion(s, s->last_mv[1][0][1], s->b_code);
-                    s->last_mv[1][1][0]= s->last_mv[1][0][0]= s->mv[1][0][0] = mx;
-                    s->last_mv[1][1][1]= s->last_mv[1][0][1]= s->mv[1][0][1] = my;
+                    s->last_mv[1][1][0] =
+                    s->last_mv[1][0][0] =
+                    s->mv[1][0][0]      = mx;
+                    s->last_mv[1][1][1] =
+                    s->last_mv[1][0][1] =
+                    s->mv[1][0][1]      = my;
                 }
-            }else if(!IS_DIRECT(mb_type)){
-                s->mv_type= MV_TYPE_FIELD;
+            } else if (!IS_DIRECT(mb_type)) {
+                s->mv_type = MV_TYPE_FIELD;
 
-                if(USES_LIST(mb_type, 0)){
+                if (USES_LIST(mb_type, 0)) {
                     s->mv_dir = MV_DIR_FORWARD;
 
-                    for(i=0; i<2; i++){
-                        mx = ff_h263_decode_motion(s, s->last_mv[0][i][0]  , s->f_code);
-                        my = ff_h263_decode_motion(s, s->last_mv[0][i][1]/2, s->f_code);
-                        s->last_mv[0][i][0]=  s->mv[0][i][0] = mx;
-                        s->last_mv[0][i][1]= (s->mv[0][i][1] = my)*2;
+                    for (i = 0; i < 2; i++) {
+                        mx = ff_h263_decode_motion(s, s->last_mv[0][i][0], s->f_code);
+                        my = ff_h263_decode_motion(s, s->last_mv[0][i][1] / 2, s->f_code);
+                        s->last_mv[0][i][0] =
+                        s->mv[0][i][0]      = mx;
+                        s->last_mv[0][i][1] = (s->mv[0][i][1] = my) * 2;
                     }
                 }
 
-                if(USES_LIST(mb_type, 1)){
+                if (USES_LIST(mb_type, 1)) {
                     s->mv_dir |= MV_DIR_BACKWARD;
 
-                    for(i=0; i<2; i++){
-                        mx = ff_h263_decode_motion(s, s->last_mv[1][i][0]  , s->b_code);
-                        my = ff_h263_decode_motion(s, s->last_mv[1][i][1]/2, s->b_code);
-                        s->last_mv[1][i][0]=  s->mv[1][i][0] = mx;
-                        s->last_mv[1][i][1]= (s->mv[1][i][1] = my)*2;
+                    for (i = 0; i < 2; i++) {
+                        mx = ff_h263_decode_motion(s, s->last_mv[1][i][0], s->b_code);
+                        my = ff_h263_decode_motion(s, s->last_mv[1][i][1] / 2, s->b_code);
+                        s->last_mv[1][i][0] =
+                        s->mv[1][i][0]      = mx;
+                        s->last_mv[1][i][1] = (s->mv[1][i][1] = my) * 2;
                     }
                 }
             }
         }
 
-        if(IS_DIRECT(mb_type)){
-            if(IS_SKIP(mb_type))
-                mx=my=0;
-            else{
+        if (IS_DIRECT(mb_type)) {
+            if (IS_SKIP(mb_type)) {
+                mx =
+                my = 0;
+            } else {
                 mx = ff_h263_decode_motion(s, 0, 1);
                 my = ff_h263_decode_motion(s, 0, 1);
             }
 
             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
-            mb_type |= ff_mpeg4_set_direct_mv(s, mx, my);
+            mb_type  |= ff_mpeg4_set_direct_mv(s, mx, my);
         }
-        s->current_picture.f.mb_type[xy] = mb_type;
+        s->current_picture.mb_type[xy] = mb_type;
     } else { /* I-Frame */
-        do{
+        do {
             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
-            if (cbpc < 0){
-                av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
+            if (cbpc < 0) {
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
                 return -1;
             }
-        }while(cbpc == 8);
+        } while (cbpc == 8);
 
         dquant = cbpc & 4;
         s->mb_intra = 1;
+
 intra:
         s->ac_pred = get_bits1(&s->gb);
-        if(s->ac_pred)
-            s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
+        if (s->ac_pred)
+            s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
         else
-            s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
+            s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 
         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
-        if(cbpy<0){
-            av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
+        if (cbpy < 0) {
+            av_log(s->avctx, AV_LOG_ERROR,
+                   "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
             return -1;
         }
         cbp = (cbpc & 3) | (cbpy << 2);
 
-        s->use_intra_dc_vlc= s->qscale < s->intra_dc_threshold;
+        ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
 
-        if (dquant) {
+        if (dquant)
             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
-        }
 
-        if(!s->progressive_sequence)
-            s->interlaced_dct= get_bits1(&s->gb);
+        if (!s->progressive_sequence)
+            s->interlaced_dct = get_bits1(&s->gb);
 
-        s->dsp.clear_blocks(s->block[0]);
+        s->bdsp.clear_blocks(s->block[0]);
         /* decode each block */
         for (i = 0; i < 6; i++) {
-            if (mpeg4_decode_block(s, block[i], i, cbp&32, 1, 0) < 0)
+            if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 1, 0) < 0)
                 return -1;
-            cbp+=cbp;
+            cbp += cbp;
         }
         goto end;
     }
 
     /* decode each block */
     for (i = 0; i < 6; i++) {
-        if (mpeg4_decode_block(s, block[i], i, cbp&32, 0, 0) < 0)
+        if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 0, 0) < 0)
             return -1;
-        cbp+=cbp;
+        cbp += cbp;
     }
-end:
 
-        /* per-MB end of slice check */
-    if(s->codec_id==AV_CODEC_ID_MPEG4){
-        if(mpeg4_is_resync(s)){
-            const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
-
-            if (s->pict_type == AV_PICTURE_TYPE_B && s->next_picture.f.mbskip_table[xy + delta]) {
-                ff_thread_await_progress(&s->next_picture_ptr->f,
-                                        (s->mb_x + delta >= s->mb_width) ? FFMIN(s->mb_y+1, s->mb_height-1) : s->mb_y, 0);
+end:
+    /* per-MB end of slice check */
+    if (s->codec_id == AV_CODEC_ID_MPEG4) {
+        if (mpeg4_is_resync(s)) {
+            const int delta = s->mb_x + 1 == s->mb_width ? 2 : 1;
+
+            if (s->pict_type == AV_PICTURE_TYPE_B &&
+                s->next_picture.mbskip_table[xy + delta]) {
+                ff_thread_await_progress(&s->next_picture_ptr->tf,
+                                         (s->mb_x + delta >= s->mb_width)
+                                         ? FFMIN(s->mb_y + 1, s->mb_height - 1)
+                                         : s->mb_y, 0);
             }
 
-            if (s->pict_type == AV_PICTURE_TYPE_B && s->next_picture.f.mbskip_table[xy + delta])
+            if (s->pict_type == AV_PICTURE_TYPE_B &&
+                s->next_picture.mbskip_table[xy + delta])
                 return SLICE_OK;
             return SLICE_END;
         }
@@ -1485,16 +1629,16 @@ end:
     return SLICE_OK;
 }
 
-
-static int mpeg4_decode_gop_header(MpegEncContext * s, GetBitContext *gb){
+static int mpeg4_decode_gop_header(MpegEncContext *s, GetBitContext *gb)
+{
     int hours, minutes, seconds;
     unsigned time_code = show_bits(gb, 18);
 
     if (time_code & 0x40) {     /* marker_bit */
         hours   = time_code >> 13;
-        minutes = time_code >>  7 & 0x3f;
-        seconds = time_code       & 0x3f;
-        s->time_base = seconds + 60*(minutes + 60*hours);
+        minutes = time_code >> 7 & 0x3f;
+        seconds = time_code & 0x3f;
+        s->time_base = seconds + 60 * (minutes + 60 * hours);
         skip_bits(gb, 20);      /* time_code, closed_gov, broken_link */
     } else {
         av_log(s->avctx, AV_LOG_WARNING, "GOP header missing marker_bit\n");
@@ -1503,49 +1647,52 @@ static int mpeg4_decode_gop_header(MpegEncContext * s, GetBitContext *gb){
     return 0;
 }
 
-static int mpeg4_decode_profile_level(MpegEncContext * s, GetBitContext *gb){
-  int profile_and_level_indication;
+static int mpeg4_decode_profile_level(MpegEncContext *s, GetBitContext *gb)
+{
+    int profile_and_level_indication;
 
-  profile_and_level_indication = get_bits(gb, 8);
+    profile_and_level_indication = get_bits(gb, 8);
 
-  s->avctx->profile = (profile_and_level_indication & 0xf0) >> 4;
-  s->avctx->level   = (profile_and_level_indication & 0x0f);
+    s->avctx->profile = (profile_and_level_indication & 0xf0) >> 4;
+    s->avctx->level   = (profile_and_level_indication & 0x0f);
 
-  // for Simple profile, level 0
-  if (s->avctx->profile == 0 && s->avctx->level == 8) {
-      s->avctx->level = 0;
-  }
+    // for Simple profile, level 0
+    if (s->avctx->profile == 0 && s->avctx->level == 8) {
+        s->avctx->level = 0;
+    }
 
-  return 0;
+    return 0;
 }
 
-static int decode_vol_header(MpegEncContext *s, GetBitContext *gb){
+static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
+{
+    MpegEncContext *s = &ctx->m;
     int width, height, vo_ver_id;
 
     /* vol header */
-    skip_bits(gb, 1); /* random access */
-    s->vo_type= get_bits(gb, 8);
-    if (get_bits1(gb) != 0) { /* is_ol_id */
-        vo_ver_id = get_bits(gb, 4); /* vo_ver_id */
-        skip_bits(gb, 3); /* vo_priority */
+    skip_bits(gb, 1);                   /* random access */
+    s->vo_type = get_bits(gb, 8);
+    if (get_bits1(gb) != 0) {           /* is_ol_id */
+        vo_ver_id = get_bits(gb, 4);    /* vo_ver_id */
+        skip_bits(gb, 3);               /* vo_priority */
     } else {
         vo_ver_id = 1;
     }
-    s->aspect_ratio_info= get_bits(gb, 4);
-    if(s->aspect_ratio_info == FF_ASPECT_EXTENDED){
-        s->avctx->sample_aspect_ratio.num= get_bits(gb, 8); // par_width
-        s->avctx->sample_aspect_ratio.den= get_bits(gb, 8); // par_height
-    }else{
-        s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
+    s->aspect_ratio_info = get_bits(gb, 4);
+    if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
+        s->avctx->sample_aspect_ratio.num = get_bits(gb, 8);  // par_width
+        s->avctx->sample_aspect_ratio.den = get_bits(gb, 8);  // par_height
+    } else {
+        s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[s->aspect_ratio_info];
     }
 
-    if ((s->vol_control_parameters=get_bits1(gb))) { /* vol control parameter */
-        int chroma_format= get_bits(gb, 2);
-        if(chroma_format!=CHROMA_420){
+    if ((ctx->vol_control_parameters = get_bits1(gb))) { /* vol control parameter */
+        int chroma_format = get_bits(gb, 2);
+        if (chroma_format != CHROMA_420)
             av_log(s->avctx, AV_LOG_ERROR, "illegal chroma format\n");
-        }
-        s->low_delay= get_bits1(gb);
-        if(get_bits1(gb)){ /* vbv parameters */
+
+        s->low_delay = get_bits1(gb);
+        if (get_bits1(gb)) {    /* vbv parameters */
             get_bits(gb, 15);   /* first_half_bitrate */
             skip_bits1(gb);     /* marker */
             get_bits(gb, 15);   /* latter_half_bitrate */
@@ -1558,273 +1705,288 @@ static int decode_vol_header(MpegEncContext *s, GetBitContext *gb){
             get_bits(gb, 15);   /* latter_half_vbv_occupancy */
             skip_bits1(gb);     /* marker */
         }
-    }else{
-        // set low delay flag only once the smartest? low delay detection won't be overriden
-        if(s->picture_number==0)
-            s->low_delay=0;
+    } else {
+        /* is setting low delay flag only once the smartest thing to do?
+         * low delay detection won't be overriden. */
+        if (s->picture_number == 0)
+            s->low_delay = 0;
     }
 
-    s->shape = get_bits(gb, 2); /* vol shape */
-    if(s->shape != RECT_SHAPE) av_log(s->avctx, AV_LOG_ERROR, "only rectangular vol supported\n");
-    if(s->shape == GRAY_SHAPE && vo_ver_id != 1){
+    ctx->shape = get_bits(gb, 2); /* vol shape */
+    if (ctx->shape != RECT_SHAPE)
+        av_log(s->avctx, AV_LOG_ERROR, "only rectangular vol supported\n");
+    if (ctx->shape == GRAY_SHAPE && vo_ver_id != 1) {
         av_log(s->avctx, AV_LOG_ERROR, "Gray shape not supported\n");
-        skip_bits(gb, 4);  //video_object_layer_shape_extension
+        skip_bits(gb, 4);  /* video_object_layer_shape_extension */
     }
 
     check_marker(gb, "before time_increment_resolution");
 
-    s->avctx->time_base.den = get_bits(gb, 16);
-    if(!s->avctx->time_base.den){
-        av_log(s->avctx, AV_LOG_ERROR, "time_base.den==0\n");
-        s->avctx->time_base.num = 0;
+    s->avctx->framerate.num = get_bits(gb, 16);
+    if (!s->avctx->framerate.num) {
+        av_log(s->avctx, AV_LOG_ERROR, "framerate==0\n");
         return -1;
     }
 
-    s->time_increment_bits = av_log2(s->avctx->time_base.den - 1) + 1;
-    if (s->time_increment_bits < 1)
-        s->time_increment_bits = 1;
+    ctx->time_increment_bits = av_log2(s->avctx->framerate.num - 1) + 1;
+    if (ctx->time_increment_bits < 1)
+        ctx->time_increment_bits = 1;
 
     check_marker(gb, "before fixed_vop_rate");
 
-    if (get_bits1(gb) != 0) {   /* fixed_vop_rate  */
-        s->avctx->time_base.num = get_bits(gb, s->time_increment_bits);
-    }else
-        s->avctx->time_base.num = 1;
+    if (get_bits1(gb) != 0)     /* fixed_vop_rate  */
+        s->avctx->framerate.den = get_bits(gb, ctx->time_increment_bits);
+    else
+        s->avctx->framerate.den = 1;
 
-    s->t_frame=0;
+    ctx->t_frame = 0;
 
-    if (s->shape != BIN_ONLY_SHAPE) {
-        if (s->shape == RECT_SHAPE) {
+    if (ctx->shape != BIN_ONLY_SHAPE) {
+        if (ctx->shape == RECT_SHAPE) {
             skip_bits1(gb);   /* marker */
             width = get_bits(gb, 13);
             skip_bits1(gb);   /* marker */
             height = get_bits(gb, 13);
             skip_bits1(gb);   /* marker */
-            if(width && height && !(s->width && s->codec_tag == AV_RL32("MP4S"))){ /* they should be non zero but who knows ... */
+            if (width && height &&  /* they should be non zero but who knows */
+                !(s->width && s->codec_tag == AV_RL32("MP4S"))) {
                 if (s->width && s->height &&
                     (s->width != width || s->height != height))
                     s->context_reinit = 1;
-                s->width = width;
+                s->width  = width;
                 s->height = height;
             }
         }
 
-        s->progressive_sequence=
-        s->progressive_frame= get_bits1(gb)^1;
-        s->interlaced_dct=0;
-        if(!get_bits1(gb) && (s->avctx->debug & FF_DEBUG_PICT_INFO))
-            av_log(s->avctx, AV_LOG_INFO, "MPEG4 OBMC not supported (very likely buggy encoder)\n");   /* OBMC Disable */
-        if (vo_ver_id == 1) {
-            s->vol_sprite_usage = get_bits1(gb); /* vol_sprite_usage */
-        } else {
-            s->vol_sprite_usage = get_bits(gb, 2); /* vol_sprite_usage */
-        }
-        if(s->vol_sprite_usage==STATIC_SPRITE) av_log(s->avctx, AV_LOG_ERROR, "Static Sprites not supported\n");
-        if(s->vol_sprite_usage==STATIC_SPRITE || s->vol_sprite_usage==GMC_SPRITE){
-            if(s->vol_sprite_usage==STATIC_SPRITE){
-                s->sprite_width = get_bits(gb, 13);
+        s->progressive_sequence  =
+        s->progressive_frame     = get_bits1(gb) ^ 1;
+        s->interlaced_dct        = 0;
+        if (!get_bits1(gb) && (s->avctx->debug & FF_DEBUG_PICT_INFO))
+            av_log(s->avctx, AV_LOG_INFO,           /* OBMC Disable */
+                   "MPEG4 OBMC not supported (very likely buggy encoder)\n");
+        if (vo_ver_id == 1)
+            ctx->vol_sprite_usage = get_bits1(gb);    /* vol_sprite_usage */
+        else
+            ctx->vol_sprite_usage = get_bits(gb, 2);  /* vol_sprite_usage */
+
+        if (ctx->vol_sprite_usage == STATIC_SPRITE)
+            av_log(s->avctx, AV_LOG_ERROR, "Static Sprites not supported\n");
+        if (ctx->vol_sprite_usage == STATIC_SPRITE ||
+            ctx->vol_sprite_usage == GMC_SPRITE) {
+            if (ctx->vol_sprite_usage == STATIC_SPRITE) {
+                skip_bits(gb, 13); // sprite_width
                 skip_bits1(gb); /* marker */
-                s->sprite_height= get_bits(gb, 13);
+                skip_bits(gb, 13); // sprite_height
                 skip_bits1(gb); /* marker */
-                s->sprite_left  = get_bits(gb, 13);
+                skip_bits(gb, 13); // sprite_left
                 skip_bits1(gb); /* marker */
-                s->sprite_top   = get_bits(gb, 13);
+                skip_bits(gb, 13); // sprite_top
                 skip_bits1(gb); /* marker */
             }
-            s->num_sprite_warping_points= get_bits(gb, 6);
-            if(s->num_sprite_warping_points > 3){
-                av_log(s->avctx, AV_LOG_ERROR, "%d sprite_warping_points\n", s->num_sprite_warping_points);
-                s->num_sprite_warping_points= 0;
+            ctx->num_sprite_warping_points = get_bits(gb, 6);
+            if (ctx->num_sprite_warping_points > 3) {
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "%d sprite_warping_points\n",
+                       ctx->num_sprite_warping_points);
+                ctx->num_sprite_warping_points = 0;
                 return -1;
             }
-            s->sprite_warping_accuracy = get_bits(gb, 2);
-            s->sprite_brightness_change= get_bits1(gb);
-            if(s->vol_sprite_usage==STATIC_SPRITE)
-                s->low_latency_sprite= get_bits1(gb);
+            s->sprite_warping_accuracy  = get_bits(gb, 2);
+            ctx->sprite_brightness_change = get_bits1(gb);
+            if (ctx->vol_sprite_usage == STATIC_SPRITE)
+                skip_bits1(gb); // low_latency_sprite
         }
         // FIXME sadct disable bit if verid!=1 && shape not rect
 
-        if (get_bits1(gb) == 1) {   /* not_8_bit */
-            s->quant_precision = get_bits(gb, 4); /* quant_precision */
-            if(get_bits(gb, 4)!=8) av_log(s->avctx, AV_LOG_ERROR, "N-bit not supported\n"); /* bits_per_pixel */
-            if(s->quant_precision!=5) av_log(s->avctx, AV_LOG_ERROR, "quant precision %d\n", s->quant_precision);
+        if (get_bits1(gb) == 1) {                   /* not_8_bit */
+            s->quant_precision = get_bits(gb, 4);   /* quant_precision */
+            if (get_bits(gb, 4) != 8)               /* bits_per_pixel */
+                av_log(s->avctx, AV_LOG_ERROR, "N-bit not supported\n");
+            if (s->quant_precision != 5)
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "quant precision %d\n", s->quant_precision);
         } else {
             s->quant_precision = 5;
         }
 
         // FIXME a bunch of grayscale shape things
 
-        if((s->mpeg_quant=get_bits1(gb))){ /* vol_quant_type */
+        if ((s->mpeg_quant = get_bits1(gb))) { /* vol_quant_type */
             int i, v;
 
             /* load default matrixes */
-            for(i=0; i<64; i++){
-                int j= s->dsp.idct_permutation[i];
-                v= ff_mpeg4_default_intra_matrix[i];
-                s->intra_matrix[j]= v;
-                s->chroma_intra_matrix[j]= v;
-
-                v= ff_mpeg4_default_non_intra_matrix[i];
-                s->inter_matrix[j]= v;
-                s->chroma_inter_matrix[j]= v;
+            for (i = 0; i < 64; i++) {
+                int j = s->idsp.idct_permutation[i];
+                v = ff_mpeg4_default_intra_matrix[i];
+                s->intra_matrix[j]        = v;
+                s->chroma_intra_matrix[j] = v;
+
+                v = ff_mpeg4_default_non_intra_matrix[i];
+                s->inter_matrix[j]        = v;
+                s->chroma_inter_matrix[j] = v;
             }
 
             /* load custom intra matrix */
-            if(get_bits1(gb)){
-                int last=0;
-                for(i=0; i<64; i++){
+            if (get_bits1(gb)) {
+                int last = 0;
+                for (i = 0; i < 64; i++) {
                     int j;
-                    v= get_bits(gb, 8);
-                    if(v==0) break;
-
-                    last= v;
-                    j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
-                    s->intra_matrix[j]= v;
-                    s->chroma_intra_matrix[j]= v;
+                    v = get_bits(gb, 8);
+                    if (v == 0)
+                        break;
+
+                    last = v;
+                    j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
+                    s->intra_matrix[j]        = last;
+                    s->chroma_intra_matrix[j] = last;
                 }
 
                 /* replicate last value */
-                for(; i<64; i++){
-                    int j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
-                    s->intra_matrix[j]= last;
-                    s->chroma_intra_matrix[j]= last;
+                for (; i < 64; i++) {
+                    int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
+                    s->intra_matrix[j]        = last;
+                    s->chroma_intra_matrix[j] = last;
                 }
             }
 
             /* load custom non intra matrix */
-            if(get_bits1(gb)){
-                int last=0;
-                for(i=0; i<64; i++){
+            if (get_bits1(gb)) {
+                int last = 0;
+                for (i = 0; i < 64; i++) {
                     int j;
-                    v= get_bits(gb, 8);
-                    if(v==0) break;
-
-                    last= v;
-                    j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
-                    s->inter_matrix[j]= v;
-                    s->chroma_inter_matrix[j]= v;
+                    v = get_bits(gb, 8);
+                    if (v == 0)
+                        break;
+
+                    last = v;
+                    j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
+                    s->inter_matrix[j]        = v;
+                    s->chroma_inter_matrix[j] = v;
                 }
 
                 /* replicate last value */
-                for(; i<64; i++){
-                    int j= s->dsp.idct_permutation[ ff_zigzag_direct[i] ];
-                    s->inter_matrix[j]= last;
-                    s->chroma_inter_matrix[j]= last;
+                for (; i < 64; i++) {
+                    int j = s->idsp.idct_permutation[ff_zigzag_direct[i]];
+                    s->inter_matrix[j]        = last;
+                    s->chroma_inter_matrix[j] = last;
                 }
             }
 
             // FIXME a bunch of grayscale shape things
         }
 
-        if(vo_ver_id != 1)
-             s->quarter_sample= get_bits1(gb);
-        else s->quarter_sample=0;
-
-        if(!get_bits1(gb)){
-            int pos= get_bits_count(gb);
-            int estimation_method= get_bits(gb, 2);
-            if(estimation_method<2){
-                if(!get_bits1(gb)){
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //opaque
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //transparent
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //intra_cae
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //inter_cae
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //no_update
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //upampling
+        if (vo_ver_id != 1)
+            s->quarter_sample = get_bits1(gb);
+        else
+            s->quarter_sample = 0;
+
+        if (!get_bits1(gb)) {
+            int pos               = get_bits_count(gb);
+            int estimation_method = get_bits(gb, 2);
+            if (estimation_method < 2) {
+                if (!get_bits1(gb)) {
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* opaque */
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* transparent */
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_cae */
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* inter_cae */
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* no_update */
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* upampling */
                 }
-                if(!get_bits1(gb)){
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //intra_blocks
-                    s->cplx_estimation_trash_p += 8*get_bits1(gb); //inter_blocks
-                    s->cplx_estimation_trash_p += 8*get_bits1(gb); //inter4v_blocks
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //not coded blocks
+                if (!get_bits1(gb)) {
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_blocks */
+                    ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter_blocks */
+                    ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter4v_blocks */
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* not coded blocks */
                 }
-                if(!check_marker(gb, "in complexity estimation part 1")){
+                if (!check_marker(gb, "in complexity estimation part 1")) {
                     skip_bits_long(gb, pos - get_bits_count(gb));
                     goto no_cplx_est;
                 }
-                if(!get_bits1(gb)){
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //dct_coeffs
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //dct_lines
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //vlc_syms
-                    s->cplx_estimation_trash_i += 4*get_bits1(gb); //vlc_bits
+                if (!get_bits1(gb)) {
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_coeffs */
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_lines */
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* vlc_syms */
+                    ctx->cplx_estimation_trash_i += 4 * get_bits1(gb);  /* vlc_bits */
                 }
-                if(!get_bits1(gb)){
-                    s->cplx_estimation_trash_p += 8*get_bits1(gb); //apm
-                    s->cplx_estimation_trash_p += 8*get_bits1(gb); //npm
-                    s->cplx_estimation_trash_b += 8*get_bits1(gb); //interpolate_mc_q
-                    s->cplx_estimation_trash_p += 8*get_bits1(gb); //forwback_mc_q
-                    s->cplx_estimation_trash_p += 8*get_bits1(gb); //halfpel2
-                    s->cplx_estimation_trash_p += 8*get_bits1(gb); //halfpel4
+                if (!get_bits1(gb)) {
+                    ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* apm */
+                    ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* npm */
+                    ctx->cplx_estimation_trash_b += 8 * get_bits1(gb);  /* interpolate_mc_q */
+                    ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* forwback_mc_q */
+                    ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel2 */
+                    ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel4 */
                 }
-                if(!check_marker(gb, "in complexity estimation part 2")){
+                if (!check_marker(gb, "in complexity estimation part 2")) {
                     skip_bits_long(gb, pos - get_bits_count(gb));
                     goto no_cplx_est;
                 }
-                if(estimation_method==1){
-                    s->cplx_estimation_trash_i += 8*get_bits1(gb); //sadct
-                    s->cplx_estimation_trash_p += 8*get_bits1(gb); //qpel
+                if (estimation_method == 1) {
+                    ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* sadct */
+                    ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* qpel */
                 }
-            }else
-                av_log(s->avctx, AV_LOG_ERROR, "Invalid Complexity estimation method %d\n", estimation_method);
-        }else{
+            } else
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "Invalid Complexity estimation method %d\n",
+                       estimation_method);
+        } else {
+
 no_cplx_est:
-            s->cplx_estimation_trash_i=
-            s->cplx_estimation_trash_p=
-            s->cplx_estimation_trash_b= 0;
+            ctx->cplx_estimation_trash_i =
+            ctx->cplx_estimation_trash_p =
+            ctx->cplx_estimation_trash_b = 0;
         }
 
-        s->resync_marker= !get_bits1(gb); /* resync_marker_disabled */
+        ctx->resync_marker = !get_bits1(gb); /* resync_marker_disabled */
 
-        s->data_partitioning= get_bits1(gb);
-        if(s->data_partitioning){
-            s->rvlc= get_bits1(gb);
-        }
+        s->data_partitioning = get_bits1(gb);
+        if (s->data_partitioning)
+            ctx->rvlc = get_bits1(gb);
 
-        if(vo_ver_id != 1) {
-            s->new_pred= get_bits1(gb);
-            if(s->new_pred){
+        if (vo_ver_id != 1) {
+            ctx->new_pred = get_bits1(gb);
+            if (ctx->new_pred) {
                 av_log(s->avctx, AV_LOG_ERROR, "new pred not supported\n");
                 skip_bits(gb, 2); /* requested upstream message type */
-                skip_bits1(gb); /* newpred segment type */
+                skip_bits1(gb);   /* newpred segment type */
             }
-            s->reduced_res_vop= get_bits1(gb);
-            if(s->reduced_res_vop) av_log(s->avctx, AV_LOG_ERROR, "reduced resolution VOP not supported\n");
-        }
-        else{
-            s->new_pred=0;
-            s->reduced_res_vop= 0;
+            if (get_bits1(gb)) // reduced_res_vop
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "reduced resolution VOP not supported\n");
+        } else {
+            ctx->new_pred = 0;
         }
 
-        s->scalability= get_bits1(gb);
+        ctx->scalability = get_bits1(gb);
 
-        if (s->scalability) {
-            GetBitContext bak= *gb;
+        if (ctx->scalability) {
+            GetBitContext bak = *gb;
             int h_sampling_factor_n;
             int h_sampling_factor_m;
             int v_sampling_factor_n;
             int v_sampling_factor_m;
 
-            s->hierachy_type= get_bits1(gb);
+            skip_bits1(gb);    // hierarchy_type
             skip_bits(gb, 4);  /* ref_layer_id */
             skip_bits1(gb);    /* ref_layer_sampling_dir */
-            h_sampling_factor_n= get_bits(gb, 5);
-            h_sampling_factor_m= get_bits(gb, 5);
-            v_sampling_factor_n= get_bits(gb, 5);
-            v_sampling_factor_m= get_bits(gb, 5);
-            s->enhancement_type= get_bits1(gb);
-
-            if(   h_sampling_factor_n==0 || h_sampling_factor_m==0
-               || v_sampling_factor_n==0 || v_sampling_factor_m==0){
+            h_sampling_factor_n = get_bits(gb, 5);
+            h_sampling_factor_m = get_bits(gb, 5);
+            v_sampling_factor_n = get_bits(gb, 5);
+            v_sampling_factor_m = get_bits(gb, 5);
+            ctx->enhancement_type = get_bits1(gb);
+
+            if (h_sampling_factor_n == 0 || h_sampling_factor_m == 0 ||
+                v_sampling_factor_n == 0 || v_sampling_factor_m == 0) {
                 /* illegal scalability header (VERY broken encoder),
                  * trying to workaround */
-                s->scalability=0;
-                *gb= bak;
-            }else
+                ctx->scalability = 0;
+                *gb            = bak;
+            } else
                 av_log(s->avctx, AV_LOG_ERROR, "scalability not supported\n");
 
             // bin shape stuff FIXME
         }
     }
+
     return 0;
 }
 
@@ -1832,270 +1994,320 @@ no_cplx_est:
  * Decode the user data stuff in the header.
  * Also initializes divx/xvid/lavc_version/build.
  */
-static int decode_user_data(MpegEncContext *s, GetBitContext *gb){
+static int decode_user_data(Mpeg4DecContext *ctx, GetBitContext *gb)
+{
+    MpegEncContext *s = &ctx->m;
     char buf[256];
     int i;
     int e;
     int ver = 0, build = 0, ver2 = 0, ver3 = 0;
     char last;
 
-    for(i=0; i<255 && get_bits_count(gb) < gb->size_in_bits; i++){
-        if(show_bits(gb, 23) == 0) break;
-        buf[i]= get_bits(gb, 8);
+    for (i = 0; i < 255 && get_bits_count(gb) < gb->size_in_bits; i++) {
+        if (show_bits(gb, 23) == 0)
+            break;
+        buf[i] = get_bits(gb, 8);
     }
-    buf[i]=0;
+    buf[i] = 0;
 
     /* divx detection */
-    e=sscanf(buf, "DivX%dBuild%d%c", &ver, &build, &last);
-    if(e<2)
-        e=sscanf(buf, "DivX%db%d%c", &ver, &build, &last);
-    if(e>=2){
-        s->divx_version= ver;
-        s->divx_build= build;
-        s->divx_packed= e==3 && last=='p';
-        if(s->divx_packed && !s->showed_packed_warning) {
-            av_log(s->avctx, AV_LOG_WARNING, "Invalid and inefficient vfw-avi packed B frames detected\n");
-            s->showed_packed_warning=1;
+    e = sscanf(buf, "DivX%dBuild%d%c", &ver, &build, &last);
+    if (e < 2)
+        e = sscanf(buf, "DivX%db%d%c", &ver, &build, &last);
+    if (e >= 2) {
+        ctx->divx_version = ver;
+        ctx->divx_build   = build;
+        s->divx_packed  = e == 3 && last == 'p';
+        if (s->divx_packed && !ctx->showed_packed_warning) {
+            av_log(s->avctx, AV_LOG_WARNING,
+                   "Invalid and inefficient vfw-avi packed B frames detected\n");
+            ctx->showed_packed_warning = 1;
         }
     }
 
     /* libavcodec detection */
-    e=sscanf(buf, "FFmpe%*[^b]b%d", &build)+3;
-    if(e!=4)
-        e=sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build);
-    if(e!=4){
-        e=sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3)+1;
-        if (e>1)
-            build= (ver<<16) + (ver2<<8) + ver3;
+    e = sscanf(buf, "FFmpe%*[^b]b%d", &build) + 3;
+    if (e != 4)
+        e = sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build);
+    if (e != 4) {
+        e = sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3) + 1;
+        if (e > 1)
+            build = (ver << 16) + (ver2 << 8) + ver3;
     }
-    if(e!=4){
-        if(strcmp(buf, "ffmpeg")==0){
-            s->lavc_build= 4600;
-        }
-    }
-    if(e==4){
-        s->lavc_build= build;
+    if (e != 4) {
+        if (strcmp(buf, "ffmpeg") == 0)
+            ctx->lavc_build = 4600;
     }
+    if (e == 4)
+        ctx->lavc_build = build;
 
     /* Xvid detection */
-    e=sscanf(buf, "XviD%d", &build);
-    if(e==1){
-        s->xvid_build= build;
+    e = sscanf(buf, "XviD%d", &build);
+    if (e == 1)
+        ctx->xvid_build = build;
+
+    if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1) {
+        if (s->codec_tag        == AV_RL32("XVID") ||
+            s->codec_tag        == AV_RL32("XVIX") ||
+            s->codec_tag        == AV_RL32("RMP4") ||
+            s->codec_tag        == AV_RL32("ZMP4") ||
+            s->codec_tag        == AV_RL32("SIPP"))
+            ctx->xvid_build = 0;
     }
 
+    if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1)
+        if (s->codec_tag == AV_RL32("DIVX") && s->vo_type == 0 &&
+            ctx->vol_control_parameters == 0)
+            ctx->divx_version = 400;  // divx 4
+
+    if (ctx->xvid_build >= 0 && ctx->divx_version >= 0) {
+        ctx->divx_version =
+        ctx->divx_build   = -1;
+    }
+
+    if (CONFIG_MPEG4_DECODER && ctx->xvid_build >= 0)
+        ff_xvid_idct_init(&s->idsp, s->avctx);
+
     return 0;
 }
 
-static int decode_vop_header(MpegEncContext *s, GetBitContext *gb){
+static int decode_vop_header(Mpeg4DecContext *ctx, GetBitContext *gb)
+{
+    MpegEncContext *s = &ctx->m;
     int time_incr, time_increment;
 
     s->pict_type = get_bits(gb, 2) + AV_PICTURE_TYPE_I;        /* pict type: I = 0 , P = 1 */
-    if(s->pict_type==AV_PICTURE_TYPE_B && s->low_delay && s->vol_control_parameters==0 && !(s->flags & CODEC_FLAG_LOW_DELAY)){
-        av_log(s->avctx, AV_LOG_ERROR, "low_delay flag incorrectly, clearing it\n");
-        s->low_delay=0;
+    if (s->pict_type == AV_PICTURE_TYPE_B && s->low_delay &&
+        ctx->vol_control_parameters == 0 && !(s->flags & CODEC_FLAG_LOW_DELAY)) {
+        av_log(s->avctx, AV_LOG_ERROR, "low_delay flag set incorrectly, clearing it\n");
+        s->low_delay = 0;
     }
 
-    s->partitioned_frame= s->data_partitioning && s->pict_type!=AV_PICTURE_TYPE_B;
-    if(s->partitioned_frame)
-        s->decode_mb= mpeg4_decode_partitioned_mb;
+    s->partitioned_frame = s->data_partitioning && s->pict_type != AV_PICTURE_TYPE_B;
+    if (s->partitioned_frame)
+        s->decode_mb = mpeg4_decode_partitioned_mb;
     else
-        s->decode_mb= mpeg4_decode_mb;
+        s->decode_mb = mpeg4_decode_mb;
 
-    time_incr=0;
+    time_incr = 0;
     while (get_bits1(gb) != 0)
         time_incr++;
 
     check_marker(gb, "before time_increment");
 
-    if(s->time_increment_bits==0 || !(show_bits(gb, s->time_increment_bits+1)&1)){
-        av_log(s->avctx, AV_LOG_ERROR, "hmm, seems the headers are not complete, trying to guess time_increment_bits\n");
-
-        for(s->time_increment_bits=1 ;s->time_increment_bits<16; s->time_increment_bits++){
-            if (    s->pict_type == AV_PICTURE_TYPE_P
-                || (s->pict_type == AV_PICTURE_TYPE_S && s->vol_sprite_usage==GMC_SPRITE)) {
-                if((show_bits(gb, s->time_increment_bits+6)&0x37) == 0x30) break;
-            }else
-                if((show_bits(gb, s->time_increment_bits+5)&0x1F) == 0x18) break;
+    if (ctx->time_increment_bits == 0 ||
+        !(show_bits(gb, ctx->time_increment_bits + 1) & 1)) {
+        av_log(s->avctx, AV_LOG_ERROR,
+               "hmm, seems the headers are not complete, trying to guess time_increment_bits\n");
+
+        for (ctx->time_increment_bits = 1;
+             ctx->time_increment_bits < 16;
+             ctx->time_increment_bits++) {
+            if (s->pict_type == AV_PICTURE_TYPE_P ||
+                (s->pict_type == AV_PICTURE_TYPE_S &&
+                 ctx->vol_sprite_usage == GMC_SPRITE)) {
+                if ((show_bits(gb, ctx->time_increment_bits + 6) & 0x37) == 0x30)
+                    break;
+            } else if ((show_bits(gb, ctx->time_increment_bits + 5) & 0x1F) == 0x18)
+                break;
         }
 
-        av_log(s->avctx, AV_LOG_ERROR, "my guess is %d bits ;)\n",s->time_increment_bits);
+        av_log(s->avctx, AV_LOG_ERROR,
+               "my guess is %d bits ;)\n", ctx->time_increment_bits);
     }
 
-    if(IS_3IV1) time_increment= get_bits1(gb); //FIXME investigate further
-    else time_increment= get_bits(gb, s->time_increment_bits);
-
-    if(s->pict_type!=AV_PICTURE_TYPE_B){
-        s->last_time_base= s->time_base;
-        s->time_base+= time_incr;
-        s->time= s->time_base*s->avctx->time_base.den + time_increment;
-        if(s->workaround_bugs&FF_BUG_UMP4){
-            if(s->time < s->last_non_b_time){
+    if (IS_3IV1)
+        time_increment = get_bits1(gb);        // FIXME investigate further
+    else
+        time_increment = get_bits(gb, ctx->time_increment_bits);
+
+    if (s->pict_type != AV_PICTURE_TYPE_B) {
+        s->last_time_base = s->time_base;
+        s->time_base     += time_incr;
+        s->time = s->time_base * s->avctx->framerate.num + time_increment;
+        if (s->workaround_bugs & FF_BUG_UMP4) {
+            if (s->time < s->last_non_b_time) {
                 /* header is not mpeg-4-compatible, broken encoder,
                  * trying to workaround */
                 s->time_base++;
-                s->time+= s->avctx->time_base.den;
+                s->time += s->avctx->framerate.num;
             }
         }
-        s->pp_time= s->time - s->last_non_b_time;
-        s->last_non_b_time= s->time;
-    }else{
-        s->time= (s->last_time_base + time_incr)*s->avctx->time_base.den + time_increment;
-        s->pb_time= s->pp_time - (s->last_non_b_time - s->time);
-        if(s->pp_time <=s->pb_time || s->pp_time <= s->pp_time - s->pb_time || s->pp_time<=0){
+        s->pp_time         = s->time - s->last_non_b_time;
+        s->last_non_b_time = s->time;
+    } else {
+        s->time    = (s->last_time_base + time_incr) * s->avctx->framerate.num + time_increment;
+        s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
+        if (s->pp_time <= s->pb_time ||
+            s->pp_time <= s->pp_time - s->pb_time ||
+            s->pp_time <= 0) {
             /* messed up order, maybe after seeking? skipping current b-frame */
             return FRAME_SKIPPED;
         }
         ff_mpeg4_init_direct_mv(s);
 
-        if(s->t_frame==0) s->t_frame= s->pb_time;
-        if(s->t_frame==0) s->t_frame=1; // 1/0 protection
-        s->pp_field_time= (  ROUNDED_DIV(s->last_non_b_time, s->t_frame)
-                           - ROUNDED_DIV(s->last_non_b_time - s->pp_time, s->t_frame))*2;
-        s->pb_field_time= (  ROUNDED_DIV(s->time, s->t_frame)
-                           - ROUNDED_DIV(s->last_non_b_time - s->pp_time, s->t_frame))*2;
-        if(!s->progressive_sequence){
-            if(s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1)
+        if (ctx->t_frame == 0)
+            ctx->t_frame = s->pb_time;
+        if (ctx->t_frame == 0)
+            ctx->t_frame = 1;  // 1/0 protection
+        s->pp_field_time = (ROUNDED_DIV(s->last_non_b_time, ctx->t_frame) -
+                            ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
+        s->pb_field_time = (ROUNDED_DIV(s->time, ctx->t_frame) -
+                            ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
+        if (!s->progressive_sequence) {
+            if (s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1)
                 return FRAME_SKIPPED;
         }
     }
 
-    if(s->avctx->time_base.num)
-        s->current_picture_ptr->f.pts = (s->time + s->avctx->time_base.num / 2) / s->avctx->time_base.num;
-    else
-        s->current_picture_ptr->f.pts = AV_NOPTS_VALUE;
-    if(s->avctx->debug&FF_DEBUG_PTS)
-        av_log(s->avctx, AV_LOG_DEBUG, "MPEG4 PTS: %"PRId64"\n",
-               s->current_picture_ptr->f.pts);
-
     check_marker(gb, "before vop_coded");
 
     /* vop coded */
-    if (get_bits1(gb) != 1){
-        if(s->avctx->debug&FF_DEBUG_PICT_INFO)
+    if (get_bits1(gb) != 1) {
+        if (s->avctx->debug & FF_DEBUG_PICT_INFO)
             av_log(s->avctx, AV_LOG_ERROR, "vop not coded\n");
         return FRAME_SKIPPED;
     }
-    if (s->shape != BIN_ONLY_SHAPE && ( s->pict_type == AV_PICTURE_TYPE_P
-                          || (s->pict_type == AV_PICTURE_TYPE_S && s->vol_sprite_usage==GMC_SPRITE))) {
+    if (ctx->shape != BIN_ONLY_SHAPE &&
+                    (s->pict_type == AV_PICTURE_TYPE_P ||
+                     (s->pict_type == AV_PICTURE_TYPE_S &&
+                      ctx->vol_sprite_usage == GMC_SPRITE))) {
         /* rounding type for motion estimation */
         s->no_rounding = get_bits1(gb);
     } else {
         s->no_rounding = 0;
     }
-//FIXME reduced res stuff
-
-     if (s->shape != RECT_SHAPE) {
-         if (s->vol_sprite_usage != 1 || s->pict_type != AV_PICTURE_TYPE_I) {
-             skip_bits(gb, 13); /* width */
-             skip_bits1(gb);   /* marker */
-             skip_bits(gb, 13); /* height */
-             skip_bits1(gb);   /* marker */
-             skip_bits(gb, 13); /* hor_spat_ref */
-             skip_bits1(gb);   /* marker */
-             skip_bits(gb, 13); /* ver_spat_ref */
-         }
-         skip_bits1(gb); /* change_CR_disable */
-
-         if (get_bits1(gb) != 0) {
-             skip_bits(gb, 8); /* constant_alpha_value */
-         }
-     }
-//FIXME complexity estimation stuff
-
-     if (s->shape != BIN_ONLY_SHAPE) {
-         skip_bits_long(gb, s->cplx_estimation_trash_i);
-         if(s->pict_type != AV_PICTURE_TYPE_I)
-            skip_bits_long(gb, s->cplx_estimation_trash_p);
-         if(s->pict_type == AV_PICTURE_TYPE_B)
-            skip_bits_long(gb, s->cplx_estimation_trash_b);
-
-         s->intra_dc_threshold= ff_mpeg4_dc_threshold[ get_bits(gb, 3) ];
-         if(!s->progressive_sequence){
-             s->top_field_first= get_bits1(gb);
-             s->alternate_scan= get_bits1(gb);
-         }else
-             s->alternate_scan= 0;
-     }
-
-     if(s->alternate_scan){
-         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable  , ff_alternate_vertical_scan);
-         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable  , ff_alternate_vertical_scan);
-         ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
-         ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
-     } else{
-         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable  , ff_zigzag_direct);
-         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable  , ff_zigzag_direct);
-         ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
-         ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
-     }
-
-     if(s->pict_type == AV_PICTURE_TYPE_S && (s->vol_sprite_usage==STATIC_SPRITE || s->vol_sprite_usage==GMC_SPRITE)){
-         mpeg4_decode_sprite_trajectory(s, gb);
-         if(s->sprite_brightness_change) av_log(s->avctx, AV_LOG_ERROR, "sprite_brightness_change not supported\n");
-         if(s->vol_sprite_usage==STATIC_SPRITE) av_log(s->avctx, AV_LOG_ERROR, "static sprite not supported\n");
-     }
-
-     if (s->shape != BIN_ONLY_SHAPE) {
-         s->chroma_qscale= s->qscale = get_bits(gb, s->quant_precision);
-         if(s->qscale==0){
-             av_log(s->avctx, AV_LOG_ERROR, "Error, header damaged or not MPEG4 header (qscale=0)\n");
-             return -1; // makes no sense to continue, as there is nothing left from the image then
-         }
-
-         if (s->pict_type != AV_PICTURE_TYPE_I) {
-             s->f_code = get_bits(gb, 3);       /* fcode_for */
-             if(s->f_code==0){
-                 av_log(s->avctx, AV_LOG_ERROR, "Error, header damaged or not MPEG4 header (f_code=0)\n");
-                 return -1; // makes no sense to continue, as the MV decoding will break very quickly
-             }
-         }else
-             s->f_code=1;
-
-         if (s->pict_type == AV_PICTURE_TYPE_B) {
-             s->b_code = get_bits(gb, 3);
-         }else
-             s->b_code=1;
-
-         if(s->avctx->debug&FF_DEBUG_PICT_INFO){
-             av_log(s->avctx, AV_LOG_DEBUG, "qp:%d fc:%d,%d %s size:%d pro:%d alt:%d top:%d %spel part:%d resync:%d w:%d a:%d rnd:%d vot:%d%s dc:%d ce:%d/%d/%d\n",
-                 s->qscale, s->f_code, s->b_code,
-                 s->pict_type == AV_PICTURE_TYPE_I ? "I" : (s->pict_type == AV_PICTURE_TYPE_P ? "P" : (s->pict_type == AV_PICTURE_TYPE_B ? "B" : "S")),
-                 gb->size_in_bits,s->progressive_sequence, s->alternate_scan, s->top_field_first,
-                 s->quarter_sample ? "q" : "h", s->data_partitioning, s->resync_marker, s->num_sprite_warping_points,
-                 s->sprite_warping_accuracy, 1-s->no_rounding, s->vo_type, s->vol_control_parameters ? " VOLC" : " ", s->intra_dc_threshold, s->cplx_estimation_trash_i, s->cplx_estimation_trash_p, s->cplx_estimation_trash_b);
-         }
-
-         if(!s->scalability){
-             if (s->shape!=RECT_SHAPE && s->pict_type!=AV_PICTURE_TYPE_I) {
-                 skip_bits1(gb); // vop shape coding type
-             }
-         }else{
-             if(s->enhancement_type){
-                 int load_backward_shape= get_bits1(gb);
-                 if(load_backward_shape){
-                     av_log(s->avctx, AV_LOG_ERROR, "load backward shape isn't supported\n");
-                 }
-             }
-             skip_bits(gb, 2); //ref_select_code
-         }
-     }
-     /* detect buggy encoders which don't set the low_delay flag (divx4/xvid/opendivx)*/
-     // note we cannot detect divx5 without b-frames easily (although it's buggy too)
-     if(s->vo_type==0 && s->vol_control_parameters==0 && s->divx_version==-1 && s->picture_number==0){
-         av_log(s->avctx, AV_LOG_WARNING, "looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag\n");
-         s->low_delay=1;
-     }
-
-     s->picture_number++; // better than pic number==0 always ;)
-
-     s->y_dc_scale_table= ff_mpeg4_y_dc_scale_table; //FIXME add short header support
-     s->c_dc_scale_table= ff_mpeg4_c_dc_scale_table;
-
-     if(s->workaround_bugs&FF_BUG_EDGE){
-         s->h_edge_pos= s->width;
-         s->v_edge_pos= s->height;
-     }
-     return 0;
+    // FIXME reduced res stuff
+
+    if (ctx->shape != RECT_SHAPE) {
+        if (ctx->vol_sprite_usage != 1 || s->pict_type != AV_PICTURE_TYPE_I) {
+            skip_bits(gb, 13);  /* width */
+            skip_bits1(gb);     /* marker */
+            skip_bits(gb, 13);  /* height */
+            skip_bits1(gb);     /* marker */
+            skip_bits(gb, 13);  /* hor_spat_ref */
+            skip_bits1(gb);     /* marker */
+            skip_bits(gb, 13);  /* ver_spat_ref */
+        }
+        skip_bits1(gb);         /* change_CR_disable */
+
+        if (get_bits1(gb) != 0)
+            skip_bits(gb, 8);   /* constant_alpha_value */
+    }
+
+    // FIXME complexity estimation stuff
+
+    if (ctx->shape != BIN_ONLY_SHAPE) {
+        skip_bits_long(gb, ctx->cplx_estimation_trash_i);
+        if (s->pict_type != AV_PICTURE_TYPE_I)
+            skip_bits_long(gb, ctx->cplx_estimation_trash_p);
+        if (s->pict_type == AV_PICTURE_TYPE_B)
+            skip_bits_long(gb, ctx->cplx_estimation_trash_b);
+
+        ctx->intra_dc_threshold = ff_mpeg4_dc_threshold[get_bits(gb, 3)];
+        if (!s->progressive_sequence) {
+            s->top_field_first = get_bits1(gb);
+            s->alternate_scan  = get_bits1(gb);
+        } else
+            s->alternate_scan = 0;
+    }
+
+    if (s->alternate_scan) {
+        ff_init_scantable(s->idsp.idct_permutation, &s->inter_scantable,   ff_alternate_vertical_scan);
+        ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable,   ff_alternate_vertical_scan);
+        ff_init_scantable(s->idsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
+        ff_init_scantable(s->idsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
+    } else {
+        ff_init_scantable(s->idsp.idct_permutation, &s->inter_scantable,   ff_zigzag_direct);
+        ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable,   ff_zigzag_direct);
+        ff_init_scantable(s->idsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
+        ff_init_scantable(s->idsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
+    }
+
+    if (s->pict_type == AV_PICTURE_TYPE_S &&
+        (ctx->vol_sprite_usage == STATIC_SPRITE ||
+         ctx->vol_sprite_usage == GMC_SPRITE)) {
+        if (mpeg4_decode_sprite_trajectory(ctx, gb) < 0)
+            return AVERROR_INVALIDDATA;
+        if (ctx->sprite_brightness_change)
+            av_log(s->avctx, AV_LOG_ERROR,
+                   "sprite_brightness_change not supported\n");
+        if (ctx->vol_sprite_usage == STATIC_SPRITE)
+            av_log(s->avctx, AV_LOG_ERROR, "static sprite not supported\n");
+    }
+
+    if (ctx->shape != BIN_ONLY_SHAPE) {
+        s->chroma_qscale = s->qscale = get_bits(gb, s->quant_precision);
+        if (s->qscale == 0) {
+            av_log(s->avctx, AV_LOG_ERROR,
+                   "Error, header damaged or not MPEG4 header (qscale=0)\n");
+            return -1;  // makes no sense to continue, as there is nothing left from the image then
+        }
+
+        if (s->pict_type != AV_PICTURE_TYPE_I) {
+            s->f_code = get_bits(gb, 3);        /* fcode_for */
+            if (s->f_code == 0) {
+                av_log(s->avctx, AV_LOG_ERROR,
+                       "Error, header damaged or not MPEG4 header (f_code=0)\n");
+                return -1;  // makes no sense to continue, as there is nothing left from the image then
+            }
+        } else
+            s->f_code = 1;
+
+        if (s->pict_type == AV_PICTURE_TYPE_B) {
+            s->b_code = get_bits(gb, 3);
+        } else
+            s->b_code = 1;
+
+        if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
+            av_log(s->avctx, AV_LOG_DEBUG,
+                   "qp:%d fc:%d,%d %s size:%d pro:%d alt:%d top:%d %spel part:%d resync:%d w:%d a:%d rnd:%d vot:%d%s dc:%d ce:%d/%d/%d\n",
+                   s->qscale, s->f_code, s->b_code,
+                   s->pict_type == AV_PICTURE_TYPE_I ? "I" : (s->pict_type == AV_PICTURE_TYPE_P ? "P" : (s->pict_type == AV_PICTURE_TYPE_B ? "B" : "S")),
+                   gb->size_in_bits, s->progressive_sequence, s->alternate_scan,
+                   s->top_field_first, s->quarter_sample ? "q" : "h",
+                   s->data_partitioning, ctx->resync_marker,
+                   ctx->num_sprite_warping_points, s->sprite_warping_accuracy,
+                   1 - s->no_rounding, s->vo_type,
+                   ctx->vol_control_parameters ? " VOLC" : " ", ctx->intra_dc_threshold,
+                   ctx->cplx_estimation_trash_i, ctx->cplx_estimation_trash_p,
+                   ctx->cplx_estimation_trash_b);
+        }
+
+        if (!ctx->scalability) {
+            if (ctx->shape != RECT_SHAPE && s->pict_type != AV_PICTURE_TYPE_I)
+                skip_bits1(gb);  // vop shape coding type
+        } else {
+            if (ctx->enhancement_type) {
+                int load_backward_shape = get_bits1(gb);
+                if (load_backward_shape)
+                    av_log(s->avctx, AV_LOG_ERROR,
+                           "load backward shape isn't supported\n");
+            }
+            skip_bits(gb, 2);  // ref_select_code
+        }
+    }
+    /* detect buggy encoders which don't set the low_delay flag
+     * (divx4/xvid/opendivx). Note we cannot detect divx5 without b-frames
+     * easily (although it's buggy too) */
+    if (s->vo_type == 0 && ctx->vol_control_parameters == 0 &&
+        ctx->divx_version == -1 && s->picture_number == 0) {
+        av_log(s->avctx, AV_LOG_WARNING,
+               "looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag\n");
+        s->low_delay = 1;
+    }
+
+    s->picture_number++;  // better than pic number==0 always ;)
+
+    // FIXME add short header support
+    s->y_dc_scale_table = ff_mpeg4_y_dc_scale_table;
+    s->c_dc_scale_table = ff_mpeg4_c_dc_scale_table;
+
+    if (s->workaround_bugs & FF_BUG_EDGE) {
+        s->h_edge_pos = s->width;
+        s->v_edge_pos = s->height;
+    }
+    return 0;
 }
 
 /**
@@ -2104,107 +2316,257 @@ static int decode_vop_header(MpegEncContext *s, GetBitContext *gb){
  *         FRAME_SKIPPED if a not coded VOP is found
  *         0 if a VOP is found
  */
-int ff_mpeg4_decode_picture_header(MpegEncContext * s, GetBitContext *gb)
+int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
 {
+    MpegEncContext *s = &ctx->m;
     unsigned startcode, v;
 
     /* search next start code */
     align_get_bits(gb);
 
-    if(s->codec_tag == AV_RL32("WV1F") && show_bits(gb, 24) == 0x575630){
+    if (s->codec_tag == AV_RL32("WV1F") && show_bits(gb, 24) == 0x575630) {
         skip_bits(gb, 24);
-        if(get_bits(gb, 8) == 0xF0)
+        if (get_bits(gb, 8) == 0xF0)
             goto end;
     }
 
     startcode = 0xff;
-    for(;;) {
-        if(get_bits_count(gb) >= gb->size_in_bits){
-            if(gb->size_in_bits==8 && (s->divx_version>=0 || s->xvid_build>=0)){
+    for (;;) {
+        if (get_bits_count(gb) >= gb->size_in_bits) {
+            if (gb->size_in_bits == 8 &&
+                (ctx->divx_version >= 0 || ctx->xvid_build >= 0)) {
                 av_log(s->avctx, AV_LOG_WARNING, "frame skip %d\n", gb->size_in_bits);
-                return FRAME_SKIPPED; //divx bug
-            }else
-                return -1; //end of stream
+                return FRAME_SKIPPED;  // divx bug
+            } else
+                return -1;  // end of stream
         }
 
         /* use the bits after the test */
         v = get_bits(gb, 8);
         startcode = ((startcode << 8) | v) & 0xffffffff;
 
-        if((startcode&0xFFFFFF00) != 0x100)
-            continue; //no startcode
+        if ((startcode & 0xFFFFFF00) != 0x100)
+            continue;  // no startcode
 
-        if(s->avctx->debug&FF_DEBUG_STARTCODE){
+        if (s->avctx->debug & FF_DEBUG_STARTCODE) {
             av_log(s->avctx, AV_LOG_DEBUG, "startcode: %3X ", startcode);
-            if     (startcode<=0x11F) av_log(s->avctx, AV_LOG_DEBUG, "Video Object Start");
-            else if(startcode<=0x12F) av_log(s->avctx, AV_LOG_DEBUG, "Video Object Layer Start");
-            else if(startcode<=0x13F) av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
-            else if(startcode<=0x15F) av_log(s->avctx, AV_LOG_DEBUG, "FGS bp start");
-            else if(startcode<=0x1AF) av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
-            else if(startcode==0x1B0) av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq Start");
-            else if(startcode==0x1B1) av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq End");
-            else if(startcode==0x1B2) av_log(s->avctx, AV_LOG_DEBUG, "User Data");
-            else if(startcode==0x1B3) av_log(s->avctx, AV_LOG_DEBUG, "Group of VOP start");
-            else if(startcode==0x1B4) av_log(s->avctx, AV_LOG_DEBUG, "Video Session Error");
-            else if(startcode==0x1B5) av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Start");
-            else if(startcode==0x1B6) av_log(s->avctx, AV_LOG_DEBUG, "Video Object Plane start");
-            else if(startcode==0x1B7) av_log(s->avctx, AV_LOG_DEBUG, "slice start");
-            else if(startcode==0x1B8) av_log(s->avctx, AV_LOG_DEBUG, "extension start");
-            else if(startcode==0x1B9) av_log(s->avctx, AV_LOG_DEBUG, "fgs start");
-            else if(startcode==0x1BA) av_log(s->avctx, AV_LOG_DEBUG, "FBA Object start");
-            else if(startcode==0x1BB) av_log(s->avctx, AV_LOG_DEBUG, "FBA Object Plane start");
-            else if(startcode==0x1BC) av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object start");
-            else if(startcode==0x1BD) av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object Plane start");
-            else if(startcode==0x1BE) av_log(s->avctx, AV_LOG_DEBUG, "Still Texture Object start");
-            else if(startcode==0x1BF) av_log(s->avctx, AV_LOG_DEBUG, "Texture Spatial Layer start");
-            else if(startcode==0x1C0) av_log(s->avctx, AV_LOG_DEBUG, "Texture SNR Layer start");
-            else if(startcode==0x1C1) av_log(s->avctx, AV_LOG_DEBUG, "Texture Tile start");
-            else if(startcode==0x1C2) av_log(s->avctx, AV_LOG_DEBUG, "Texture Shape Layer start");
-            else if(startcode==0x1C3) av_log(s->avctx, AV_LOG_DEBUG, "stuffing start");
-            else if(startcode<=0x1C5) av_log(s->avctx, AV_LOG_DEBUG, "reserved");
-            else if(startcode<=0x1FF) av_log(s->avctx, AV_LOG_DEBUG, "System start");
+            if (startcode <= 0x11F)
+                av_log(s->avctx, AV_LOG_DEBUG, "Video Object Start");
+            else if (startcode <= 0x12F)
+                av_log(s->avctx, AV_LOG_DEBUG, "Video Object Layer Start");
+            else if (startcode <= 0x13F)
+                av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
+            else if (startcode <= 0x15F)
+                av_log(s->avctx, AV_LOG_DEBUG, "FGS bp start");
+            else if (startcode <= 0x1AF)
+                av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
+            else if (startcode == 0x1B0)
+                av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq Start");
+            else if (startcode == 0x1B1)
+                av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq End");
+            else if (startcode == 0x1B2)
+                av_log(s->avctx, AV_LOG_DEBUG, "User Data");
+            else if (startcode == 0x1B3)
+                av_log(s->avctx, AV_LOG_DEBUG, "Group of VOP start");
+            else if (startcode == 0x1B4)
+                av_log(s->avctx, AV_LOG_DEBUG, "Video Session Error");
+            else if (startcode == 0x1B5)
+                av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Start");
+            else if (startcode == 0x1B6)
+                av_log(s->avctx, AV_LOG_DEBUG, "Video Object Plane start");
+            else if (startcode == 0x1B7)
+                av_log(s->avctx, AV_LOG_DEBUG, "slice start");
+            else if (startcode == 0x1B8)
+                av_log(s->avctx, AV_LOG_DEBUG, "extension start");
+            else if (startcode == 0x1B9)
+                av_log(s->avctx, AV_LOG_DEBUG, "fgs start");
+            else if (startcode == 0x1BA)
+                av_log(s->avctx, AV_LOG_DEBUG, "FBA Object start");
+            else if (startcode == 0x1BB)
+                av_log(s->avctx, AV_LOG_DEBUG, "FBA Object Plane start");
+            else if (startcode == 0x1BC)
+                av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object start");
+            else if (startcode == 0x1BD)
+                av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object Plane start");
+            else if (startcode == 0x1BE)
+                av_log(s->avctx, AV_LOG_DEBUG, "Still Texture Object start");
+            else if (startcode == 0x1BF)
+                av_log(s->avctx, AV_LOG_DEBUG, "Texture Spatial Layer start");
+            else if (startcode == 0x1C0)
+                av_log(s->avctx, AV_LOG_DEBUG, "Texture SNR Layer start");
+            else if (startcode == 0x1C1)
+                av_log(s->avctx, AV_LOG_DEBUG, "Texture Tile start");
+            else if (startcode == 0x1C2)
+                av_log(s->avctx, AV_LOG_DEBUG, "Texture Shape Layer start");
+            else if (startcode == 0x1C3)
+                av_log(s->avctx, AV_LOG_DEBUG, "stuffing start");
+            else if (startcode <= 0x1C5)
+                av_log(s->avctx, AV_LOG_DEBUG, "reserved");
+            else if (startcode <= 0x1FF)
+                av_log(s->avctx, AV_LOG_DEBUG, "System start");
             av_log(s->avctx, AV_LOG_DEBUG, " at %d\n", get_bits_count(gb));
         }
 
-        if(startcode >= 0x120 && startcode <= 0x12F){
-            if(decode_vol_header(s, gb) < 0)
+        if (startcode >= 0x120 && startcode <= 0x12F) {
+            if (decode_vol_header(ctx, gb) < 0)
                 return -1;
-        }
-        else if(startcode == USER_DATA_STARTCODE){
-            decode_user_data(s, gb);
-        }
-        else if(startcode == GOP_STARTCODE){
+        } else if (startcode == USER_DATA_STARTCODE) {
+            decode_user_data(ctx, gb);
+        } else if (startcode == GOP_STARTCODE) {
             mpeg4_decode_gop_header(s, gb);
-        }
-        else if(startcode == VOS_STARTCODE){
+        } else if (startcode == VOS_STARTCODE) {
             mpeg4_decode_profile_level(s, gb);
-        }
-        else if(startcode == VOP_STARTCODE){
+        } else if (startcode == VOP_STARTCODE) {
             break;
         }
 
         align_get_bits(gb);
         startcode = 0xff;
     }
+
 end:
-    if(s->flags& CODEC_FLAG_LOW_DELAY)
-        s->low_delay=1;
-    s->avctx->has_b_frames= !s->low_delay;
-    return decode_vop_header(s, gb);
+    if (s->flags & CODEC_FLAG_LOW_DELAY)
+        s->low_delay = 1;
+    s->avctx->has_b_frames = !s->low_delay;
+
+    if (s->workaround_bugs & FF_BUG_AUTODETECT) {
+        if (s->codec_tag == AV_RL32("XVIX"))
+            s->workaround_bugs |= FF_BUG_XVID_ILACE;
+
+        if (s->codec_tag == AV_RL32("UMP4"))
+            s->workaround_bugs |= FF_BUG_UMP4;
+
+        if (ctx->divx_version >= 500 && ctx->divx_build < 1814)
+            s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
+
+        if (ctx->divx_version > 502 && ctx->divx_build < 1814)
+            s->workaround_bugs |= FF_BUG_QPEL_CHROMA2;
+
+        if (ctx->xvid_build <= 3U)
+            s->padding_bug_score = 256 * 256 * 256 * 64;
+
+        if (ctx->xvid_build <= 1U)
+            s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
+
+        if (ctx->xvid_build <= 12U)
+            s->workaround_bugs |= FF_BUG_EDGE;
+
+        if (ctx->xvid_build <= 32U)
+            s->workaround_bugs |= FF_BUG_DC_CLIP;
+
+        if (ctx->lavc_build < 4653U)
+            s->workaround_bugs |= FF_BUG_STD_QPEL;
+
+        if (ctx->lavc_build < 4655U)
+            s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
+
+        if (ctx->lavc_build < 4670U)
+            s->workaround_bugs |= FF_BUG_EDGE;
+
+        if (ctx->lavc_build <= 4712U)
+            s->workaround_bugs |= FF_BUG_DC_CLIP;
+
+        if (ctx->divx_version >= 0)
+            s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
+
+        if (ctx->divx_version == 501 && ctx->divx_build == 20020416)
+            s->padding_bug_score = 256 * 256 * 256 * 64;
+
+        if (ctx->divx_version < 500U)
+            s->workaround_bugs |= FF_BUG_EDGE;
+
+        if (ctx->divx_version >= 0)
+            s->workaround_bugs |= FF_BUG_HPEL_CHROMA;
+    }
+
+
+    if (s->avctx->debug & FF_DEBUG_BUGS)
+        av_log(s->avctx, AV_LOG_DEBUG,
+               "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
+               s->workaround_bugs, ctx->lavc_build, ctx->xvid_build,
+               ctx->divx_version, ctx->divx_build, s->divx_packed ? "p" : "");
+
+    return decode_vop_header(ctx, gb);
+}
+
+int ff_mpeg4_frame_end(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
+{
+    Mpeg4DecContext *ctx = avctx->priv_data;
+    MpegEncContext    *s = &ctx->m;
+
+    /* divx 5.01+ bistream reorder stuff */
+    if (s->divx_packed) {
+        int current_pos     = get_bits_count(&s->gb) >> 3;
+        int startcode_found = 0;
+
+        if (buf_size - current_pos > 5) {
+            int i;
+            for (i = current_pos; i < buf_size - 3; i++)
+                if (buf[i]     == 0 &&
+                    buf[i + 1] == 0 &&
+                    buf[i + 2] == 1 &&
+                    buf[i + 3] == 0xB6) {
+                    startcode_found = 1;
+                    break;
+                }
+        }
+        if (s->gb.buffer == s->bitstream_buffer && buf_size > 7 &&
+            ctx->xvid_build >= 0) {       // xvid style
+            startcode_found = 1;
+            current_pos     = 0;
+        }
+
+        if (startcode_found) {
+            av_fast_malloc(&s->bitstream_buffer,
+                           &s->allocated_bitstream_buffer_size,
+                           buf_size - current_pos +
+                           FF_INPUT_BUFFER_PADDING_SIZE);
+            if (!s->bitstream_buffer)
+                return AVERROR(ENOMEM);
+            memcpy(s->bitstream_buffer, buf + current_pos,
+                   buf_size - current_pos);
+            s->bitstream_buffer_size = buf_size - current_pos;
+        }
+    }
+
+    return 0;
+}
+
+static int mpeg4_update_thread_context(AVCodecContext *dst,
+                                       const AVCodecContext *src)
+{
+    Mpeg4DecContext *s = dst->priv_data;
+    const Mpeg4DecContext *s1 = src->priv_data;
+    int init = s->m.context_initialized;
+
+    int ret = ff_mpeg_update_thread_context(dst, src);
+
+    if (ret < 0)
+        return ret;
+
+    if (CONFIG_MPEG4_DECODER && !init && s1->xvid_build >= 0)
+        ff_xvid_idct_init(&s->m.idsp, dst);
+
+    s->shape               = s1->shape;
+    s->time_increment_bits = s1->time_increment_bits;
+    s->xvid_build          = s1->xvid_build;
+
+    return 0;
 }
 
 static av_cold int decode_init(AVCodecContext *avctx)
 {
-    MpegEncContext *s = avctx->priv_data;
+    Mpeg4DecContext *ctx = avctx->priv_data;
+    MpegEncContext *s = &ctx->m;
     int ret;
     static int done = 0;
 
-    s->divx_version=
-    s->divx_build=
-    s->xvid_build=
-    s->lavc_build= -1;
+    ctx->divx_version =
+    ctx->divx_build   =
+    ctx->xvid_build   =
+    ctx->lavc_build   = -1;
 
-    if((ret=ff_h263_decode_init(avctx)) < 0)
+    if ((ret = ff_h263_decode_init(avctx)) < 0)
         return ret;
 
     if (!done) {
@@ -2217,24 +2579,26 @@ static av_cold int decode_init(AVCodecContext *avctx)
         INIT_VLC_RL(ff_rvlc_rl_inter, 1072);
         INIT_VLC_RL(ff_rvlc_rl_intra, 1072);
         INIT_VLC_STATIC(&dc_lum, DC_VLC_BITS, 10 /* 13 */,
-                 &ff_mpeg4_DCtab_lum[0][1], 2, 1,
-                 &ff_mpeg4_DCtab_lum[0][0], 2, 1, 512);
+                        &ff_mpeg4_DCtab_lum[0][1], 2, 1,
+                        &ff_mpeg4_DCtab_lum[0][0], 2, 1, 512);
         INIT_VLC_STATIC(&dc_chrom, DC_VLC_BITS, 10 /* 13 */,
-                 &ff_mpeg4_DCtab_chrom[0][1], 2, 1,
-                 &ff_mpeg4_DCtab_chrom[0][0], 2, 1, 512);
+                        &ff_mpeg4_DCtab_chrom[0][1], 2, 1,
+                        &ff_mpeg4_DCtab_chrom[0][0], 2, 1, 512);
         INIT_VLC_STATIC(&sprite_trajectory, SPRITE_TRAJ_VLC_BITS, 15,
-                 &ff_sprite_trajectory_tab[0][1], 4, 2,
-                 &ff_sprite_trajectory_tab[0][0], 4, 2, 128);
+                        &ff_sprite_trajectory_tab[0][1], 4, 2,
+                        &ff_sprite_trajectory_tab[0][0], 4, 2, 128);
         INIT_VLC_STATIC(&mb_type_b_vlc, MB_TYPE_B_VLC_BITS, 4,
-                 &ff_mb_type_b_tab[0][1], 2, 1,
-                 &ff_mb_type_b_tab[0][0], 2, 1, 16);
+                        &ff_mb_type_b_tab[0][1], 2, 1,
+                        &ff_mb_type_b_tab[0][0], 2, 1, 16);
     }
 
     s->h263_pred = 1;
-    s->low_delay = 0; //default, might be overriden in the vol header during header parsing
-    s->decode_mb= mpeg4_decode_mb;
-    s->time_increment_bits = 4; /* default value for broken headers */
+    s->low_delay = 0; /* default, might be overriden in the vol header during header parsing */
+    s->decode_mb = mpeg4_decode_mb;
+    ctx->time_increment_bits = 4; /* default value for broken headers */
+
     avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
+    avctx->internal->allocate_progress = 1;
 
     return 0;
 }
@@ -2260,9 +2624,10 @@ static const AVProfile mpeg4_video_profiles[] = {
 
 AVCodec ff_mpeg4_decoder = {
     .name                  = "mpeg4",
+    .long_name             = NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
     .type                  = AVMEDIA_TYPE_VIDEO,
     .id                    = AV_CODEC_ID_MPEG4,
-    .priv_data_size        = sizeof(MpegEncContext),
+    .priv_data_size        = sizeof(Mpeg4DecContext),
     .init                  = decode_init,
     .close                 = ff_h263_decode_end,
     .decode                = ff_h263_decode_frame,
@@ -2270,26 +2635,7 @@ AVCodec ff_mpeg4_decoder = {
                              CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
                              CODEC_CAP_FRAME_THREADS,
     .flush                 = ff_mpeg_flush,
-    .long_name             = NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
     .pix_fmts              = ff_h263_hwaccel_pixfmt_list_420,
     .profiles              = NULL_IF_CONFIG_SMALL(mpeg4_video_profiles),
-    .update_thread_context = ONLY_IF_THREADS_ENABLED(ff_mpeg_update_thread_context),
-};
-
-
-#if CONFIG_MPEG4_VDPAU_DECODER
-AVCodec ff_mpeg4_vdpau_decoder = {
-    .name           = "mpeg4_vdpau",
-    .type           = AVMEDIA_TYPE_VIDEO,
-    .id             = AV_CODEC_ID_MPEG4,
-    .priv_data_size = sizeof(MpegEncContext),
-    .init           = decode_init,
-    .close          = ff_h263_decode_end,
-    .decode         = ff_h263_decode_frame,
-    .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
-                      CODEC_CAP_HWACCEL_VDPAU,
-    .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 (VDPAU)"),
-    .pix_fmts       = (const enum AVPixelFormat[]){ AV_PIX_FMT_VDPAU_MPEG4,
-                                                  AV_PIX_FMT_NONE },
+    .update_thread_context = ONLY_IF_THREADS_ENABLED(mpeg4_update_thread_context),
 };
-#endif