avcodec/mpeg4videodec: fix mcbpc error messages
[ffmpeg.git] / libavcodec / mpeg4videodec.c
1 /*
2  * MPEG4 decoder.
3  * Copyright (c) 2000,2001 Fabrice Bellard
4  * Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22
23 #define UNCHECKED_BITSTREAM_READER 1
24
25 #include "libavutil/opt.h"
26 #include "error_resilience.h"
27 #include "internal.h"
28 #include "mpegutils.h"
29 #include "mpegvideo.h"
30 #include "mpeg4video.h"
31 #include "h263.h"
32 #include "thread.h"
33
34 /* The defines below define the number of bits that are read at once for
35  * reading vlc values. Changing these may improve speed and data cache needs
36  * be aware though that decreasing them may need the number of stages that is
37  * passed to get_vlc* to be increased. */
38 #define SPRITE_TRAJ_VLC_BITS 6
39 #define DC_VLC_BITS 9
40 #define MB_TYPE_B_VLC_BITS 4
41
42 static VLC dc_lum, dc_chrom;
43 static VLC sprite_trajectory;
44 static VLC mb_type_b_vlc;
45
46 static const int mb_type_b_map[4] = {
47     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
48     MB_TYPE_L0L1    | MB_TYPE_16x16,
49     MB_TYPE_L1      | MB_TYPE_16x16,
50     MB_TYPE_L0      | MB_TYPE_16x16,
51 };
52
53 /**
54  * Predict the ac.
55  * @param n block index (0-3 are luma, 4-5 are chroma)
56  * @param dir the ac prediction direction
57  */
58 void ff_mpeg4_pred_ac(MpegEncContext *s, int16_t *block, int n, int dir)
59 {
60     int i;
61     int16_t *ac_val, *ac_val1;
62     int8_t *const qscale_table = s->current_picture.qscale_table;
63
64     /* find prediction */
65     ac_val  = s->ac_val[0][0] + s->block_index[n] * 16;
66     ac_val1 = ac_val;
67     if (s->ac_pred) {
68         if (dir == 0) {
69             const int xy = s->mb_x - 1 + s->mb_y * s->mb_stride;
70             /* left prediction */
71             ac_val -= 16;
72
73             if (s->mb_x == 0 || s->qscale == qscale_table[xy] ||
74                 n == 1 || n == 3) {
75                 /* same qscale */
76                 for (i = 1; i < 8; i++)
77                     block[s->dsp.idct_permutation[i << 3]] += ac_val[i];
78             } else {
79                 /* different qscale, we must rescale */
80                 for (i = 1; i < 8; i++)
81                     block[s->dsp.idct_permutation[i << 3]] += ROUNDED_DIV(ac_val[i] * qscale_table[xy], s->qscale);
82             }
83         } else {
84             const int xy = s->mb_x + s->mb_y * s->mb_stride - s->mb_stride;
85             /* top prediction */
86             ac_val -= 16 * s->block_wrap[n];
87
88             if (s->mb_y == 0 || s->qscale == qscale_table[xy] ||
89                 n == 2 || n == 3) {
90                 /* same qscale */
91                 for (i = 1; i < 8; i++)
92                     block[s->dsp.idct_permutation[i]] += ac_val[i + 8];
93             } else {
94                 /* different qscale, we must rescale */
95                 for (i = 1; i < 8; i++)
96                     block[s->dsp.idct_permutation[i]] += ROUNDED_DIV(ac_val[i + 8] * qscale_table[xy], s->qscale);
97             }
98         }
99     }
100     /* left copy */
101     for (i = 1; i < 8; i++)
102         ac_val1[i] = block[s->dsp.idct_permutation[i << 3]];
103
104     /* top copy */
105     for (i = 1; i < 8; i++)
106         ac_val1[8 + i] = block[s->dsp.idct_permutation[i]];
107 }
108
109 /**
110  * check if the next stuff is a resync marker or the end.
111  * @return 0 if not
112  */
113 static inline int mpeg4_is_resync(Mpeg4DecContext *ctx)
114 {
115     MpegEncContext *s = &ctx->m;
116     int bits_count = get_bits_count(&s->gb);
117     int v          = show_bits(&s->gb, 16);
118
119     if (s->workaround_bugs & FF_BUG_NO_PADDING && !ctx->resync_marker)
120         return 0;
121
122     while (v <= 0xFF) {
123         if (s->pict_type == AV_PICTURE_TYPE_B ||
124             (v >> (8 - s->pict_type) != 1) || s->partitioned_frame)
125             break;
126         skip_bits(&s->gb, 8 + s->pict_type);
127         bits_count += 8 + s->pict_type;
128         v = show_bits(&s->gb, 16);
129     }
130
131     if (bits_count + 8 >= s->gb.size_in_bits) {
132         v >>= 8;
133         v  |= 0x7F >> (7 - (bits_count & 7));
134
135         if (v == 0x7F)
136             return s->mb_num;
137     } else {
138         if (v == ff_mpeg4_resync_prefix[bits_count & 7]) {
139             int len, mb_num;
140             int mb_num_bits = av_log2(s->mb_num - 1) + 1;
141             GetBitContext gb = s->gb;
142
143             skip_bits(&s->gb, 1);
144             align_get_bits(&s->gb);
145
146             for (len = 0; len < 32; len++)
147                 if (get_bits1(&s->gb))
148                     break;
149
150             mb_num = get_bits(&s->gb, mb_num_bits);
151             if (!mb_num || mb_num > s->mb_num || get_bits_count(&s->gb)+6 > s->gb.size_in_bits)
152                 mb_num= -1;
153
154             s->gb = gb;
155
156             if (len >= ff_mpeg4_get_video_packet_prefix_length(s))
157                 return mb_num;
158         }
159     }
160     return 0;
161 }
162
163 static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *gb)
164 {
165     MpegEncContext *s = &ctx->m;
166     int a     = 2 << s->sprite_warping_accuracy;
167     int rho   = 3  - s->sprite_warping_accuracy;
168     int r     = 16 / a;
169     int alpha = 0;
170     int beta  = 0;
171     int w     = s->width;
172     int h     = s->height;
173     int min_ab, i, w2, h2, w3, h3;
174     int sprite_ref[4][2];
175     int virtual_ref[2][2];
176
177     // only true for rectangle shapes
178     const int vop_ref[4][2] = { { 0, 0 },         { s->width, 0 },
179                                 { 0, s->height }, { s->width, s->height } };
180     int d[4][2]             = { { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } };
181
182     if (w <= 0 || h <= 0)
183         return AVERROR_INVALIDDATA;
184
185     for (i = 0; i < ctx->num_sprite_warping_points; i++) {
186         int length;
187         int x = 0, y = 0;
188
189         length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
190         if (length)
191             x = get_xbits(gb, length);
192
193         if (!(ctx->divx_version == 500 && ctx->divx_build == 413))
194             skip_bits1(gb);     /* marker bit */
195
196         length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
197         if (length)
198             y = get_xbits(gb, length);
199
200         skip_bits1(gb);         /* marker bit */
201         ctx->sprite_traj[i][0] = d[i][0] = x;
202         ctx->sprite_traj[i][1] = d[i][1] = y;
203     }
204     for (; i < 4; i++)
205         ctx->sprite_traj[i][0] = ctx->sprite_traj[i][1] = 0;
206
207     while ((1 << alpha) < w)
208         alpha++;
209     while ((1 << beta) < h)
210         beta++;  /* typo in the mpeg4 std for the definition of w' and h' */
211     w2 = 1 << alpha;
212     h2 = 1 << beta;
213
214     // Note, the 4th point isn't used for GMC
215     if (ctx->divx_version == 500 && ctx->divx_build == 413) {
216         sprite_ref[0][0] = a * vop_ref[0][0] + d[0][0];
217         sprite_ref[0][1] = a * vop_ref[0][1] + d[0][1];
218         sprite_ref[1][0] = a * vop_ref[1][0] + d[0][0] + d[1][0];
219         sprite_ref[1][1] = a * vop_ref[1][1] + d[0][1] + d[1][1];
220         sprite_ref[2][0] = a * vop_ref[2][0] + d[0][0] + d[2][0];
221         sprite_ref[2][1] = a * vop_ref[2][1] + d[0][1] + d[2][1];
222     } else {
223         sprite_ref[0][0] = (a >> 1) * (2 * vop_ref[0][0] + d[0][0]);
224         sprite_ref[0][1] = (a >> 1) * (2 * vop_ref[0][1] + d[0][1]);
225         sprite_ref[1][0] = (a >> 1) * (2 * vop_ref[1][0] + d[0][0] + d[1][0]);
226         sprite_ref[1][1] = (a >> 1) * (2 * vop_ref[1][1] + d[0][1] + d[1][1]);
227         sprite_ref[2][0] = (a >> 1) * (2 * vop_ref[2][0] + d[0][0] + d[2][0]);
228         sprite_ref[2][1] = (a >> 1) * (2 * vop_ref[2][1] + d[0][1] + d[2][1]);
229     }
230     /* sprite_ref[3][0] = (a >> 1) * (2 * vop_ref[3][0] + d[0][0] + d[1][0] + d[2][0] + d[3][0]);
231      * sprite_ref[3][1] = (a >> 1) * (2 * vop_ref[3][1] + d[0][1] + d[1][1] + d[2][1] + d[3][1]); */
232
233     /* this is mostly identical to the mpeg4 std (and is totally unreadable
234      * because of that...). Perhaps it should be reordered to be more readable.
235      * The idea behind this virtual_ref mess is to be able to use shifts later
236      * per pixel instead of divides so the distance between points is converted
237      * from w&h based to w2&h2 based which are of the 2^x form. */
238     virtual_ref[0][0] = 16 * (vop_ref[0][0] + w2) +
239                          ROUNDED_DIV(((w - w2) *
240                                       (r * sprite_ref[0][0] - 16 * vop_ref[0][0]) +
241                                       w2 * (r * sprite_ref[1][0] - 16 * vop_ref[1][0])), w);
242     virtual_ref[0][1] = 16 * vop_ref[0][1] +
243                         ROUNDED_DIV(((w - w2) *
244                                      (r * sprite_ref[0][1] - 16 * vop_ref[0][1]) +
245                                      w2 * (r * sprite_ref[1][1] - 16 * vop_ref[1][1])), w);
246     virtual_ref[1][0] = 16 * vop_ref[0][0] +
247                         ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][0] - 16 * vop_ref[0][0]) +
248                                      h2 * (r * sprite_ref[2][0] - 16 * vop_ref[2][0])), h);
249     virtual_ref[1][1] = 16 * (vop_ref[0][1] + h2) +
250                         ROUNDED_DIV(((h - h2) * (r * sprite_ref[0][1] - 16 * vop_ref[0][1]) +
251                                      h2 * (r * sprite_ref[2][1] - 16 * vop_ref[2][1])), h);
252
253     switch (ctx->num_sprite_warping_points) {
254     case 0:
255         s->sprite_offset[0][0] =
256         s->sprite_offset[0][1] =
257         s->sprite_offset[1][0] =
258         s->sprite_offset[1][1] = 0;
259         s->sprite_delta[0][0]  = a;
260         s->sprite_delta[0][1]  =
261         s->sprite_delta[1][0]  = 0;
262         s->sprite_delta[1][1]  = a;
263         ctx->sprite_shift[0]   =
264         ctx->sprite_shift[1]   = 0;
265         break;
266     case 1:     // GMC only
267         s->sprite_offset[0][0] = sprite_ref[0][0] - a * vop_ref[0][0];
268         s->sprite_offset[0][1] = sprite_ref[0][1] - a * vop_ref[0][1];
269         s->sprite_offset[1][0] = ((sprite_ref[0][0] >> 1) | (sprite_ref[0][0] & 1)) -
270                                  a * (vop_ref[0][0] / 2);
271         s->sprite_offset[1][1] = ((sprite_ref[0][1] >> 1) | (sprite_ref[0][1] & 1)) -
272                                  a * (vop_ref[0][1] / 2);
273         s->sprite_delta[0][0]  = a;
274         s->sprite_delta[0][1]  =
275         s->sprite_delta[1][0]  = 0;
276         s->sprite_delta[1][1]  = a;
277         ctx->sprite_shift[0]   =
278         ctx->sprite_shift[1]   = 0;
279         break;
280     case 2:
281         s->sprite_offset[0][0] = (sprite_ref[0][0] << (alpha + rho)) +
282                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
283                                  (-vop_ref[0][0]) +
284                                  (r * sprite_ref[0][1] - virtual_ref[0][1]) *
285                                  (-vop_ref[0][1]) + (1 << (alpha + rho - 1));
286         s->sprite_offset[0][1] = (sprite_ref[0][1] << (alpha + rho)) +
287                                  (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
288                                  (-vop_ref[0][0]) +
289                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
290                                  (-vop_ref[0][1]) + (1 << (alpha + rho - 1));
291         s->sprite_offset[1][0] = ((-r * sprite_ref[0][0] + virtual_ref[0][0]) *
292                                   (-2 * vop_ref[0][0] + 1) +
293                                   (r * sprite_ref[0][1] - virtual_ref[0][1]) *
294                                   (-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
295                                   sprite_ref[0][0] - 16 * w2 + (1 << (alpha + rho + 1)));
296         s->sprite_offset[1][1] = ((-r * sprite_ref[0][1] + virtual_ref[0][1]) *
297                                   (-2 * vop_ref[0][0] + 1) +
298                                   (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
299                                   (-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
300                                   sprite_ref[0][1] - 16 * w2 + (1 << (alpha + rho + 1)));
301         s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
302         s->sprite_delta[0][1] = (+r * sprite_ref[0][1] - virtual_ref[0][1]);
303         s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]);
304         s->sprite_delta[1][1] = (-r * sprite_ref[0][0] + virtual_ref[0][0]);
305
306         ctx->sprite_shift[0]  = alpha + rho;
307         ctx->sprite_shift[1]  = alpha + rho + 2;
308         break;
309     case 3:
310         min_ab = FFMIN(alpha, beta);
311         w3     = w2 >> min_ab;
312         h3     = h2 >> min_ab;
313         s->sprite_offset[0][0] = (sprite_ref[0][0] << (alpha + beta + rho - min_ab)) +
314                                  (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
315                                  h3 * (-vop_ref[0][0]) +
316                                  (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
317                                  w3 * (-vop_ref[0][1]) +
318                                  (1 << (alpha + beta + rho - min_ab - 1));
319         s->sprite_offset[0][1] = (sprite_ref[0][1] << (alpha + beta + rho - min_ab)) +
320                                  (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
321                                  h3 * (-vop_ref[0][0]) +
322                                  (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
323                                  w3 * (-vop_ref[0][1]) +
324                                  (1 << (alpha + beta + rho - min_ab - 1));
325         s->sprite_offset[1][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
326                                  h3 * (-2 * vop_ref[0][0] + 1) +
327                                  (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
328                                  w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
329                                  r * sprite_ref[0][0] - 16 * w2 * h3 +
330                                  (1 << (alpha + beta + rho - min_ab + 1));
331         s->sprite_offset[1][1] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
332                                  h3 * (-2 * vop_ref[0][0] + 1) +
333                                  (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
334                                  w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
335                                  r * sprite_ref[0][1] - 16 * w2 * h3 +
336                                  (1 << (alpha + beta + rho - min_ab + 1));
337         s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3;
338         s->sprite_delta[0][1] = (-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3;
339         s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3;
340         s->sprite_delta[1][1] = (-r * sprite_ref[0][1] + virtual_ref[1][1]) * w3;
341
342         ctx->sprite_shift[0]  = alpha + beta + rho - min_ab;
343         ctx->sprite_shift[1]  = alpha + beta + rho - min_ab + 2;
344         break;
345     }
346     /* try to simplify the situation */
347     if (s->sprite_delta[0][0] == a << ctx->sprite_shift[0] &&
348         s->sprite_delta[0][1] == 0 &&
349         s->sprite_delta[1][0] == 0 &&
350         s->sprite_delta[1][1] == a << ctx->sprite_shift[0]) {
351         s->sprite_offset[0][0] >>= ctx->sprite_shift[0];
352         s->sprite_offset[0][1] >>= ctx->sprite_shift[0];
353         s->sprite_offset[1][0] >>= ctx->sprite_shift[1];
354         s->sprite_offset[1][1] >>= ctx->sprite_shift[1];
355         s->sprite_delta[0][0] = a;
356         s->sprite_delta[0][1] = 0;
357         s->sprite_delta[1][0] = 0;
358         s->sprite_delta[1][1] = a;
359         ctx->sprite_shift[0] = 0;
360         ctx->sprite_shift[1] = 0;
361         s->real_sprite_warping_points = 1;
362     } else {
363         int shift_y = 16 - ctx->sprite_shift[0];
364         int shift_c = 16 - ctx->sprite_shift[1];
365         for (i = 0; i < 2; i++) {
366             s->sprite_offset[0][i] <<= shift_y;
367             s->sprite_offset[1][i] <<= shift_c;
368             s->sprite_delta[0][i]  <<= shift_y;
369             s->sprite_delta[1][i]  <<= shift_y;
370             ctx->sprite_shift[i]     = 16;
371         }
372         s->real_sprite_warping_points = ctx->num_sprite_warping_points;
373     }
374
375     return 0;
376 }
377
378 static int decode_new_pred(Mpeg4DecContext *ctx, GetBitContext *gb) {
379     int len = FFMIN(ctx->time_increment_bits + 3, 15);
380
381     get_bits(gb, len);
382     if (get_bits1(gb))
383         get_bits(gb, len);
384     check_marker(gb, "after new_pred");
385
386     return 0;
387 }
388
389 /**
390  * Decode the next video packet.
391  * @return <0 if something went wrong
392  */
393 int ff_mpeg4_decode_video_packet_header(Mpeg4DecContext *ctx)
394 {
395     MpegEncContext *s = &ctx->m;
396
397     int mb_num_bits      = av_log2(s->mb_num - 1) + 1;
398     int header_extension = 0, mb_num, len;
399
400     /* is there enough space left for a video packet + header */
401     if (get_bits_count(&s->gb) > s->gb.size_in_bits - 20)
402         return -1;
403
404     for (len = 0; len < 32; len++)
405         if (get_bits1(&s->gb))
406             break;
407
408     if (len != ff_mpeg4_get_video_packet_prefix_length(s)) {
409         av_log(s->avctx, AV_LOG_ERROR, "marker does not match f_code\n");
410         return -1;
411     }
412
413     if (ctx->shape != RECT_SHAPE) {
414         header_extension = get_bits1(&s->gb);
415         // FIXME more stuff here
416     }
417
418     mb_num = get_bits(&s->gb, mb_num_bits);
419     if (mb_num >= s->mb_num) {
420         av_log(s->avctx, AV_LOG_ERROR,
421                "illegal mb_num in video packet (%d %d) \n", mb_num, s->mb_num);
422         return -1;
423     }
424
425     s->mb_x = mb_num % s->mb_width;
426     s->mb_y = mb_num / s->mb_width;
427
428     if (ctx->shape != BIN_ONLY_SHAPE) {
429         int qscale = get_bits(&s->gb, s->quant_precision);
430         if (qscale)
431             s->chroma_qscale = s->qscale = qscale;
432     }
433
434     if (ctx->shape == RECT_SHAPE)
435         header_extension = get_bits1(&s->gb);
436
437     if (header_extension) {
438         int time_incr = 0;
439
440         while (get_bits1(&s->gb) != 0)
441             time_incr++;
442
443         check_marker(&s->gb, "before time_increment in video packed header");
444         skip_bits(&s->gb, ctx->time_increment_bits);      /* time_increment */
445         check_marker(&s->gb, "before vop_coding_type in video packed header");
446
447         skip_bits(&s->gb, 2); /* vop coding type */
448         // FIXME not rect stuff here
449
450         if (ctx->shape != BIN_ONLY_SHAPE) {
451             skip_bits(&s->gb, 3); /* intra dc vlc threshold */
452             // FIXME don't just ignore everything
453             if (s->pict_type == AV_PICTURE_TYPE_S &&
454                 ctx->vol_sprite_usage == GMC_SPRITE) {
455                 if (mpeg4_decode_sprite_trajectory(ctx, &s->gb) < 0)
456                     return AVERROR_INVALIDDATA;
457                 av_log(s->avctx, AV_LOG_ERROR, "untested\n");
458             }
459
460             // FIXME reduced res stuff here
461
462             if (s->pict_type != AV_PICTURE_TYPE_I) {
463                 int f_code = get_bits(&s->gb, 3);       /* fcode_for */
464                 if (f_code == 0)
465                     av_log(s->avctx, AV_LOG_ERROR,
466                            "Error, video packet header damaged (f_code=0)\n");
467             }
468             if (s->pict_type == AV_PICTURE_TYPE_B) {
469                 int b_code = get_bits(&s->gb, 3);
470                 if (b_code == 0)
471                     av_log(s->avctx, AV_LOG_ERROR,
472                            "Error, video packet header damaged (b_code=0)\n");
473             }
474         }
475     }
476     if (ctx->new_pred)
477         decode_new_pred(ctx, &s->gb);
478
479     return 0;
480 }
481
482 /**
483  * Get the average motion vector for a GMC MB.
484  * @param n either 0 for the x component or 1 for y
485  * @return the average MV for a GMC MB
486  */
487 static inline int get_amv(Mpeg4DecContext *ctx, int n)
488 {
489     MpegEncContext *s = &ctx->m;
490     int x, y, mb_v, sum, dx, dy, shift;
491     int len     = 1 << (s->f_code + 4);
492     const int a = s->sprite_warping_accuracy;
493
494     if (s->workaround_bugs & FF_BUG_AMV)
495         len >>= s->quarter_sample;
496
497     if (s->real_sprite_warping_points == 1) {
498         if (ctx->divx_version == 500 && ctx->divx_build == 413)
499             sum = s->sprite_offset[0][n] / (1 << (a - s->quarter_sample));
500         else
501             sum = RSHIFT(s->sprite_offset[0][n] << s->quarter_sample, a);
502     } else {
503         dx    = s->sprite_delta[n][0];
504         dy    = s->sprite_delta[n][1];
505         shift = ctx->sprite_shift[0];
506         if (n)
507             dy -= 1 << (shift + a + 1);
508         else
509             dx -= 1 << (shift + a + 1);
510         mb_v = s->sprite_offset[0][n] + dx * s->mb_x * 16 + dy * s->mb_y * 16;
511
512         sum = 0;
513         for (y = 0; y < 16; y++) {
514             int v;
515
516             v = mb_v + dy * y;
517             // FIXME optimize
518             for (x = 0; x < 16; x++) {
519                 sum += v >> shift;
520                 v   += dx;
521             }
522         }
523         sum = RSHIFT(sum, a + 8 - s->quarter_sample);
524     }
525
526     if (sum < -len)
527         sum = -len;
528     else if (sum >= len)
529         sum = len - 1;
530
531     return sum;
532 }
533
534 /**
535  * Decode the dc value.
536  * @param n block index (0-3 are luma, 4-5 are chroma)
537  * @param dir_ptr the prediction direction will be stored here
538  * @return the quantized dc
539  */
540 static inline int mpeg4_decode_dc(MpegEncContext *s, int n, int *dir_ptr)
541 {
542     int level, code;
543
544     if (n < 4)
545         code = get_vlc2(&s->gb, dc_lum.table, DC_VLC_BITS, 1);
546     else
547         code = get_vlc2(&s->gb, dc_chrom.table, DC_VLC_BITS, 1);
548
549     if (code < 0 || code > 9 /* && s->nbit < 9 */) {
550         av_log(s->avctx, AV_LOG_ERROR, "illegal dc vlc\n");
551         return -1;
552     }
553
554     if (code == 0) {
555         level = 0;
556     } else {
557         if (IS_3IV1) {
558             if (code == 1)
559                 level = 2 * get_bits1(&s->gb) - 1;
560             else {
561                 if (get_bits1(&s->gb))
562                     level = get_bits(&s->gb, code - 1) + (1 << (code - 1));
563                 else
564                     level = -get_bits(&s->gb, code - 1) - (1 << (code - 1));
565             }
566         } else {
567             level = get_xbits(&s->gb, code);
568         }
569
570         if (code > 8) {
571             if (get_bits1(&s->gb) == 0) { /* marker */
572                 if (s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT)) {
573                     av_log(s->avctx, AV_LOG_ERROR, "dc marker bit missing\n");
574                     return -1;
575                 }
576             }
577         }
578     }
579
580     return ff_mpeg4_pred_dc(s, n, level, dir_ptr, 0);
581 }
582
583 /**
584  * Decode first partition.
585  * @return number of MBs decoded or <0 if an error occurred
586  */
587 static int mpeg4_decode_partition_a(Mpeg4DecContext *ctx)
588 {
589     MpegEncContext *s = &ctx->m;
590     int mb_num = 0;
591     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
592
593     /* decode first partition */
594     s->first_slice_line = 1;
595     for (; s->mb_y < s->mb_height; s->mb_y++) {
596         ff_init_block_index(s);
597         for (; s->mb_x < s->mb_width; s->mb_x++) {
598             const int xy = s->mb_x + s->mb_y * s->mb_stride;
599             int cbpc;
600             int dir = 0;
601
602             mb_num++;
603             ff_update_block_index(s);
604             if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
605                 s->first_slice_line = 0;
606
607             if (s->pict_type == AV_PICTURE_TYPE_I) {
608                 int i;
609
610                 do {
611                     if (show_bits_long(&s->gb, 19) == DC_MARKER)
612                         return mb_num - 1;
613
614                     cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
615                     if (cbpc < 0) {
616                         av_log(s->avctx, AV_LOG_ERROR,
617                                "mcbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
618                         return -1;
619                     }
620                 } while (cbpc == 8);
621
622                 s->cbp_table[xy]               = cbpc & 3;
623                 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
624                 s->mb_intra                    = 1;
625
626                 if (cbpc & 4)
627                     ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
628
629                 s->current_picture.qscale_table[xy] = s->qscale;
630
631                 s->mbintra_table[xy] = 1;
632                 for (i = 0; i < 6; i++) {
633                     int dc_pred_dir;
634                     int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
635                     if (dc < 0) {
636                         av_log(s->avctx, AV_LOG_ERROR,
637                                "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
638                         return -1;
639                     }
640                     dir <<= 1;
641                     if (dc_pred_dir)
642                         dir |= 1;
643                 }
644                 s->pred_dir_table[xy] = dir;
645             } else { /* P/S_TYPE */
646                 int mx, my, pred_x, pred_y, bits;
647                 int16_t *const mot_val = s->current_picture.motion_val[0][s->block_index[0]];
648                 const int stride       = s->b8_stride * 2;
649
650 try_again:
651                 bits = show_bits(&s->gb, 17);
652                 if (bits == MOTION_MARKER)
653                     return mb_num - 1;
654
655                 skip_bits1(&s->gb);
656                 if (bits & 0x10000) {
657                     /* skip mb */
658                     if (s->pict_type == AV_PICTURE_TYPE_S &&
659                         ctx->vol_sprite_usage == GMC_SPRITE) {
660                         s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
661                                                          MB_TYPE_16x16 |
662                                                          MB_TYPE_GMC   |
663                                                          MB_TYPE_L0;
664                         mx = get_amv(ctx, 0);
665                         my = get_amv(ctx, 1);
666                     } else {
667                         s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
668                                                          MB_TYPE_16x16 |
669                                                          MB_TYPE_L0;
670                         mx = my = 0;
671                     }
672                     mot_val[0]          =
673                     mot_val[2]          =
674                     mot_val[0 + stride] =
675                     mot_val[2 + stride] = mx;
676                     mot_val[1]          =
677                     mot_val[3]          =
678                     mot_val[1 + stride] =
679                     mot_val[3 + stride] = my;
680
681                     if (s->mbintra_table[xy])
682                         ff_clean_intra_table_entries(s);
683                     continue;
684                 }
685
686                 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
687                 if (cbpc < 0) {
688                     av_log(s->avctx, AV_LOG_ERROR,
689                            "mcbpc corrupted at %d %d\n", s->mb_x, s->mb_y);
690                     return -1;
691                 }
692                 if (cbpc == 20)
693                     goto try_again;
694
695                 s->cbp_table[xy] = cbpc & (8 + 3);  // 8 is dquant
696
697                 s->mb_intra = ((cbpc & 4) != 0);
698
699                 if (s->mb_intra) {
700                     s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
701                     s->mbintra_table[xy] = 1;
702                     mot_val[0]          =
703                     mot_val[2]          =
704                     mot_val[0 + stride] =
705                     mot_val[2 + stride] = 0;
706                     mot_val[1]          =
707                     mot_val[3]          =
708                     mot_val[1 + stride] =
709                     mot_val[3 + stride] = 0;
710                 } else {
711                     if (s->mbintra_table[xy])
712                         ff_clean_intra_table_entries(s);
713
714                     if (s->pict_type == AV_PICTURE_TYPE_S &&
715                         ctx->vol_sprite_usage == GMC_SPRITE &&
716                         (cbpc & 16) == 0)
717                         s->mcsel = get_bits1(&s->gb);
718                     else
719                         s->mcsel = 0;
720
721                     if ((cbpc & 16) == 0) {
722                         /* 16x16 motion prediction */
723
724                         ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
725                         if (!s->mcsel) {
726                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
727                             if (mx >= 0xffff)
728                                 return -1;
729
730                             my = ff_h263_decode_motion(s, pred_y, s->f_code);
731                             if (my >= 0xffff)
732                                 return -1;
733                             s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
734                                                              MB_TYPE_L0;
735                         } else {
736                             mx = get_amv(ctx, 0);
737                             my = get_amv(ctx, 1);
738                             s->current_picture.mb_type[xy] = MB_TYPE_16x16 |
739                                                              MB_TYPE_GMC   |
740                                                              MB_TYPE_L0;
741                         }
742
743                         mot_val[0]          =
744                         mot_val[2]          =
745                         mot_val[0 + stride] =
746                         mot_val[2 + stride] = mx;
747                         mot_val[1]          =
748                         mot_val[3]          =
749                         mot_val[1 + stride] =
750                         mot_val[3 + stride] = my;
751                     } else {
752                         int i;
753                         s->current_picture.mb_type[xy] = MB_TYPE_8x8 |
754                                                          MB_TYPE_L0;
755                         for (i = 0; i < 4; i++) {
756                             int16_t *mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
757                             mx = ff_h263_decode_motion(s, pred_x, s->f_code);
758                             if (mx >= 0xffff)
759                                 return -1;
760
761                             my = ff_h263_decode_motion(s, pred_y, s->f_code);
762                             if (my >= 0xffff)
763                                 return -1;
764                             mot_val[0] = mx;
765                             mot_val[1] = my;
766                         }
767                     }
768                 }
769             }
770         }
771         s->mb_x = 0;
772     }
773
774     return mb_num;
775 }
776
777 /**
778  * decode second partition.
779  * @return <0 if an error occurred
780  */
781 static int mpeg4_decode_partition_b(MpegEncContext *s, int mb_count)
782 {
783     int mb_num = 0;
784     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
785
786     s->mb_x = s->resync_mb_x;
787     s->first_slice_line = 1;
788     for (s->mb_y = s->resync_mb_y; mb_num < mb_count; s->mb_y++) {
789         ff_init_block_index(s);
790         for (; mb_num < mb_count && s->mb_x < s->mb_width; s->mb_x++) {
791             const int xy = s->mb_x + s->mb_y * s->mb_stride;
792
793             mb_num++;
794             ff_update_block_index(s);
795             if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1)
796                 s->first_slice_line = 0;
797
798             if (s->pict_type == AV_PICTURE_TYPE_I) {
799                 int ac_pred = get_bits1(&s->gb);
800                 int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
801                 if (cbpy < 0) {
802                     av_log(s->avctx, AV_LOG_ERROR,
803                            "cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
804                     return -1;
805                 }
806
807                 s->cbp_table[xy]               |= cbpy << 2;
808                 s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
809             } else { /* P || S_TYPE */
810                 if (IS_INTRA(s->current_picture.mb_type[xy])) {
811                     int i;
812                     int dir     = 0;
813                     int ac_pred = get_bits1(&s->gb);
814                     int cbpy    = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
815
816                     if (cbpy < 0) {
817                         av_log(s->avctx, AV_LOG_ERROR,
818                                "I cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
819                         return -1;
820                     }
821
822                     if (s->cbp_table[xy] & 8)
823                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
824                     s->current_picture.qscale_table[xy] = s->qscale;
825
826                     for (i = 0; i < 6; i++) {
827                         int dc_pred_dir;
828                         int dc = mpeg4_decode_dc(s, i, &dc_pred_dir);
829                         if (dc < 0) {
830                             av_log(s->avctx, AV_LOG_ERROR,
831                                    "DC corrupted at %d %d\n", s->mb_x, s->mb_y);
832                             return -1;
833                         }
834                         dir <<= 1;
835                         if (dc_pred_dir)
836                             dir |= 1;
837                     }
838                     s->cbp_table[xy]               &= 3;  // remove dquant
839                     s->cbp_table[xy]               |= cbpy << 2;
840                     s->current_picture.mb_type[xy] |= ac_pred * MB_TYPE_ACPRED;
841                     s->pred_dir_table[xy]           = dir;
842                 } else if (IS_SKIP(s->current_picture.mb_type[xy])) {
843                     s->current_picture.qscale_table[xy] = s->qscale;
844                     s->cbp_table[xy]                    = 0;
845                 } else {
846                     int cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
847
848                     if (cbpy < 0) {
849                         av_log(s->avctx, AV_LOG_ERROR,
850                                "P cbpy corrupted at %d %d\n", s->mb_x, s->mb_y);
851                         return -1;
852                     }
853
854                     if (s->cbp_table[xy] & 8)
855                         ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
856                     s->current_picture.qscale_table[xy] = s->qscale;
857
858                     s->cbp_table[xy] &= 3;  // remove dquant
859                     s->cbp_table[xy] |= (cbpy ^ 0xf) << 2;
860                 }
861             }
862         }
863         if (mb_num >= mb_count)
864             return 0;
865         s->mb_x = 0;
866     }
867     return 0;
868 }
869
870 /**
871  * Decode the first and second partition.
872  * @return <0 if error (and sets error type in the error_status_table)
873  */
874 int ff_mpeg4_decode_partitions(Mpeg4DecContext *ctx)
875 {
876     MpegEncContext *s = &ctx->m;
877     int mb_num;
878     const int part_a_error = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_ERROR | ER_MV_ERROR) : ER_MV_ERROR;
879     const int part_a_end   = s->pict_type == AV_PICTURE_TYPE_I ? (ER_DC_END   | ER_MV_END)   : ER_MV_END;
880
881     mb_num = mpeg4_decode_partition_a(ctx);
882     if (mb_num < 0) {
883         ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
884                         s->mb_x, s->mb_y, part_a_error);
885         return -1;
886     }
887
888     if (s->resync_mb_x + s->resync_mb_y * s->mb_width + mb_num > s->mb_num) {
889         av_log(s->avctx, AV_LOG_ERROR, "slice below monitor ...\n");
890         ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
891                         s->mb_x, s->mb_y, part_a_error);
892         return -1;
893     }
894
895     s->mb_num_left = mb_num;
896
897     if (s->pict_type == AV_PICTURE_TYPE_I) {
898         while (show_bits(&s->gb, 9) == 1)
899             skip_bits(&s->gb, 9);
900         if (get_bits_long(&s->gb, 19) != DC_MARKER) {
901             av_log(s->avctx, AV_LOG_ERROR,
902                    "marker missing after first I partition at %d %d\n",
903                    s->mb_x, s->mb_y);
904             return -1;
905         }
906     } else {
907         while (show_bits(&s->gb, 10) == 1)
908             skip_bits(&s->gb, 10);
909         if (get_bits(&s->gb, 17) != MOTION_MARKER) {
910             av_log(s->avctx, AV_LOG_ERROR,
911                    "marker missing after first P partition at %d %d\n",
912                    s->mb_x, s->mb_y);
913             return -1;
914         }
915     }
916     ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
917                     s->mb_x - 1, s->mb_y, part_a_end);
918
919     if (mpeg4_decode_partition_b(s, mb_num) < 0) {
920         if (s->pict_type == AV_PICTURE_TYPE_P)
921             ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
922                             s->mb_x, s->mb_y, ER_DC_ERROR);
923         return -1;
924     } else {
925         if (s->pict_type == AV_PICTURE_TYPE_P)
926             ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
927                             s->mb_x - 1, s->mb_y, ER_DC_END);
928     }
929
930     return 0;
931 }
932
933 /**
934  * Decode a block.
935  * @return <0 if an error occurred
936  */
937 static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
938                                      int n, int coded, int intra, int rvlc)
939 {
940     MpegEncContext *s = &ctx->m;
941     int level, i, last, run, qmul, qadd;
942     int av_uninit(dc_pred_dir);
943     RLTable *rl;
944     RL_VLC_ELEM *rl_vlc;
945     const uint8_t *scan_table;
946
947     // Note intra & rvlc should be optimized away if this is inlined
948
949     if (intra) {
950         if (ctx->use_intra_dc_vlc) {
951             /* DC coef */
952             if (s->partitioned_frame) {
953                 level = s->dc_val[0][s->block_index[n]];
954                 if (n < 4)
955                     level = FASTDIV((level + (s->y_dc_scale >> 1)), s->y_dc_scale);
956                 else
957                     level = FASTDIV((level + (s->c_dc_scale >> 1)), s->c_dc_scale);
958                 dc_pred_dir = (s->pred_dir_table[s->mb_x + s->mb_y * s->mb_stride] << n) & 32;
959             } else {
960                 level = mpeg4_decode_dc(s, n, &dc_pred_dir);
961                 if (level < 0)
962                     return -1;
963             }
964             block[0] = level;
965             i        = 0;
966         } else {
967             i = -1;
968             ff_mpeg4_pred_dc(s, n, 0, &dc_pred_dir, 0);
969         }
970         if (!coded)
971             goto not_coded;
972
973         if (rvlc) {
974             rl     = &ff_rvlc_rl_intra;
975             rl_vlc = ff_rvlc_rl_intra.rl_vlc[0];
976         } else {
977             rl     = &ff_mpeg4_rl_intra;
978             rl_vlc = ff_mpeg4_rl_intra.rl_vlc[0];
979         }
980         if (s->ac_pred) {
981             if (dc_pred_dir == 0)
982                 scan_table = s->intra_v_scantable.permutated;  /* left */
983             else
984                 scan_table = s->intra_h_scantable.permutated;  /* top */
985         } else {
986             scan_table = s->intra_scantable.permutated;
987         }
988         qmul = 1;
989         qadd = 0;
990     } else {
991         i = -1;
992         if (!coded) {
993             s->block_last_index[n] = i;
994             return 0;
995         }
996         if (rvlc)
997             rl = &ff_rvlc_rl_inter;
998         else
999             rl = &ff_h263_rl_inter;
1000
1001         scan_table = s->intra_scantable.permutated;
1002
1003         if (s->mpeg_quant) {
1004             qmul = 1;
1005             qadd = 0;
1006             if (rvlc)
1007                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[0];
1008             else
1009                 rl_vlc = ff_h263_rl_inter.rl_vlc[0];
1010         } else {
1011             qmul = s->qscale << 1;
1012             qadd = (s->qscale - 1) | 1;
1013             if (rvlc)
1014                 rl_vlc = ff_rvlc_rl_inter.rl_vlc[s->qscale];
1015             else
1016                 rl_vlc = ff_h263_rl_inter.rl_vlc[s->qscale];
1017         }
1018     }
1019     {
1020         OPEN_READER(re, &s->gb);
1021         for (;;) {
1022             UPDATE_CACHE(re, &s->gb);
1023             GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 0);
1024             if (level == 0) {
1025                 /* escape */
1026                 if (rvlc) {
1027                     if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1028                         av_log(s->avctx, AV_LOG_ERROR,
1029                                "1. marker bit missing in rvlc esc\n");
1030                         return -1;
1031                     }
1032                     SKIP_CACHE(re, &s->gb, 1);
1033
1034                     last = SHOW_UBITS(re, &s->gb, 1);
1035                     SKIP_CACHE(re, &s->gb, 1);
1036                     run = SHOW_UBITS(re, &s->gb, 6);
1037                     SKIP_COUNTER(re, &s->gb, 1 + 1 + 6);
1038                     UPDATE_CACHE(re, &s->gb);
1039
1040                     if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1041                         av_log(s->avctx, AV_LOG_ERROR,
1042                                "2. marker bit missing in rvlc esc\n");
1043                         return -1;
1044                     }
1045                     SKIP_CACHE(re, &s->gb, 1);
1046
1047                     level = SHOW_UBITS(re, &s->gb, 11);
1048                     SKIP_CACHE(re, &s->gb, 11);
1049
1050                     if (SHOW_UBITS(re, &s->gb, 5) != 0x10) {
1051                         av_log(s->avctx, AV_LOG_ERROR, "reverse esc missing\n");
1052                         return -1;
1053                     }
1054                     SKIP_CACHE(re, &s->gb, 5);
1055
1056                     level = level * qmul + qadd;
1057                     level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1058                     SKIP_COUNTER(re, &s->gb, 1 + 11 + 5 + 1);
1059
1060                     i += run + 1;
1061                     if (last)
1062                         i += 192;
1063                 } else {
1064                     int cache;
1065                     cache = GET_CACHE(re, &s->gb);
1066
1067                     if (IS_3IV1)
1068                         cache ^= 0xC0000000;
1069
1070                     if (cache & 0x80000000) {
1071                         if (cache & 0x40000000) {
1072                             /* third escape */
1073                             SKIP_CACHE(re, &s->gb, 2);
1074                             last = SHOW_UBITS(re, &s->gb, 1);
1075                             SKIP_CACHE(re, &s->gb, 1);
1076                             run = SHOW_UBITS(re, &s->gb, 6);
1077                             SKIP_COUNTER(re, &s->gb, 2 + 1 + 6);
1078                             UPDATE_CACHE(re, &s->gb);
1079
1080                             if (IS_3IV1) {
1081                                 level = SHOW_SBITS(re, &s->gb, 12);
1082                                 LAST_SKIP_BITS(re, &s->gb, 12);
1083                             } else {
1084                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1085                                     av_log(s->avctx, AV_LOG_ERROR,
1086                                            "1. marker bit missing in 3. esc\n");
1087                                     if (!(s->err_recognition & AV_EF_IGNORE_ERR))
1088                                         return -1;
1089                                 }
1090                                 SKIP_CACHE(re, &s->gb, 1);
1091
1092                                 level = SHOW_SBITS(re, &s->gb, 12);
1093                                 SKIP_CACHE(re, &s->gb, 12);
1094
1095                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1096                                     av_log(s->avctx, AV_LOG_ERROR,
1097                                            "2. marker bit missing in 3. esc\n");
1098                                     if (!(s->err_recognition & AV_EF_IGNORE_ERR))
1099                                         return -1;
1100                                 }
1101
1102                                 SKIP_COUNTER(re, &s->gb, 1 + 12 + 1);
1103                             }
1104
1105 #if 0
1106                             if (s->error_recognition >= FF_ER_COMPLIANT) {
1107                                 const int abs_level= FFABS(level);
1108                                 if (abs_level<=MAX_LEVEL && run<=MAX_RUN) {
1109                                     const int run1= run - rl->max_run[last][abs_level] - 1;
1110                                     if (abs_level <= rl->max_level[last][run]) {
1111                                         av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, vlc encoding possible\n");
1112                                         return -1;
1113                                     }
1114                                     if (s->error_recognition > FF_ER_COMPLIANT) {
1115                                         if (abs_level <= rl->max_level[last][run]*2) {
1116                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 1 encoding possible\n");
1117                                             return -1;
1118                                         }
1119                                         if (run1 >= 0 && abs_level <= rl->max_level[last][run1]) {
1120                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 2 encoding possible\n");
1121                                             return -1;
1122                                         }
1123                                     }
1124                                 }
1125                             }
1126 #endif
1127                             if (level > 0)
1128                                 level = level * qmul + qadd;
1129                             else
1130                                 level = level * qmul - qadd;
1131
1132                             if ((unsigned)(level + 2048) > 4095) {
1133                                 if (s->err_recognition & (AV_EF_BITSTREAM|AV_EF_AGGRESSIVE)) {
1134                                     if (level > 2560 || level < -2560) {
1135                                         av_log(s->avctx, AV_LOG_ERROR,
1136                                                "|level| overflow in 3. esc, qp=%d\n",
1137                                                s->qscale);
1138                                         return -1;
1139                                     }
1140                                 }
1141                                 level = level < 0 ? -2048 : 2047;
1142                             }
1143
1144                             i += run + 1;
1145                             if (last)
1146                                 i += 192;
1147                         } else {
1148                             /* second escape */
1149                             SKIP_BITS(re, &s->gb, 2);
1150                             GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1151                             i    += run + rl->max_run[run >> 7][level / qmul] + 1;  // FIXME opt indexing
1152                             level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1153                             LAST_SKIP_BITS(re, &s->gb, 1);
1154                         }
1155                     } else {
1156                         /* first escape */
1157                         SKIP_BITS(re, &s->gb, 1);
1158                         GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1159                         i    += run;
1160                         level = level + rl->max_level[run >> 7][(run - 1) & 63] * qmul;  // FIXME opt indexing
1161                         level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1162                         LAST_SKIP_BITS(re, &s->gb, 1);
1163                     }
1164                 }
1165             } else {
1166                 i    += run;
1167                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1168                 LAST_SKIP_BITS(re, &s->gb, 1);
1169             }
1170             if (i > 62) {
1171                 i -= 192;
1172                 if (i & (~63)) {
1173                     av_log(s->avctx, AV_LOG_ERROR,
1174                            "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1175                     return -1;
1176                 }
1177
1178                 block[scan_table[i]] = level;
1179                 break;
1180             }
1181
1182             block[scan_table[i]] = level;
1183         }
1184         CLOSE_READER(re, &s->gb);
1185     }
1186
1187 not_coded:
1188     if (intra) {
1189         if (!ctx->use_intra_dc_vlc) {
1190             block[0] = ff_mpeg4_pred_dc(s, n, block[0], &dc_pred_dir, 0);
1191
1192             i -= i >> 31;  // if (i == -1) i = 0;
1193         }
1194
1195         ff_mpeg4_pred_ac(s, block, n, dc_pred_dir);
1196         if (s->ac_pred)
1197             i = 63;  // FIXME not optimal
1198     }
1199     s->block_last_index[n] = i;
1200     return 0;
1201 }
1202
1203 /**
1204  * decode partition C of one MB.
1205  * @return <0 if an error occurred
1206  */
1207 static int mpeg4_decode_partitioned_mb(MpegEncContext *s, int16_t block[6][64])
1208 {
1209     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1210     int cbp, mb_type;
1211     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1212
1213     mb_type = s->current_picture.mb_type[xy];
1214     cbp     = s->cbp_table[xy];
1215
1216     ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1217
1218     if (s->current_picture.qscale_table[xy] != s->qscale)
1219         ff_set_qscale(s, s->current_picture.qscale_table[xy]);
1220
1221     if (s->pict_type == AV_PICTURE_TYPE_P ||
1222         s->pict_type == AV_PICTURE_TYPE_S) {
1223         int i;
1224         for (i = 0; i < 4; i++) {
1225             s->mv[0][i][0] = s->current_picture.motion_val[0][s->block_index[i]][0];
1226             s->mv[0][i][1] = s->current_picture.motion_val[0][s->block_index[i]][1];
1227         }
1228         s->mb_intra = IS_INTRA(mb_type);
1229
1230         if (IS_SKIP(mb_type)) {
1231             /* skip mb */
1232             for (i = 0; i < 6; i++)
1233                 s->block_last_index[i] = -1;
1234             s->mv_dir  = MV_DIR_FORWARD;
1235             s->mv_type = MV_TYPE_16X16;
1236             if (s->pict_type == AV_PICTURE_TYPE_S
1237                 && ctx->vol_sprite_usage == GMC_SPRITE) {
1238                 s->mcsel      = 1;
1239                 s->mb_skipped = 0;
1240             } else {
1241                 s->mcsel      = 0;
1242                 s->mb_skipped = 1;
1243             }
1244         } else if (s->mb_intra) {
1245             s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
1246         } else if (!s->mb_intra) {
1247             // s->mcsel = 0;  // FIXME do we need to init that?
1248
1249             s->mv_dir = MV_DIR_FORWARD;
1250             if (IS_8X8(mb_type)) {
1251                 s->mv_type = MV_TYPE_8X8;
1252             } else {
1253                 s->mv_type = MV_TYPE_16X16;
1254             }
1255         }
1256     } else { /* I-Frame */
1257         s->mb_intra = 1;
1258         s->ac_pred  = IS_ACPRED(s->current_picture.mb_type[xy]);
1259     }
1260
1261     if (!IS_SKIP(mb_type)) {
1262         int i;
1263         s->dsp.clear_blocks(s->block[0]);
1264         /* decode each block */
1265         for (i = 0; i < 6; i++) {
1266             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, s->mb_intra, ctx->rvlc) < 0) {
1267                 av_log(s->avctx, AV_LOG_ERROR,
1268                        "texture corrupted at %d %d %d\n",
1269                        s->mb_x, s->mb_y, s->mb_intra);
1270                 return -1;
1271             }
1272             cbp += cbp;
1273         }
1274     }
1275
1276     /* per-MB end of slice check */
1277     if (--s->mb_num_left <= 0) {
1278         if (mpeg4_is_resync(ctx))
1279             return SLICE_END;
1280         else
1281             return SLICE_NOEND;
1282     } else {
1283         if (mpeg4_is_resync(ctx)) {
1284             const int delta = s->mb_x + 1 == s->mb_width ? 2 : 1;
1285             if (s->cbp_table[xy + delta])
1286                 return SLICE_END;
1287         }
1288         return SLICE_OK;
1289     }
1290 }
1291
1292 static int mpeg4_decode_mb(MpegEncContext *s, int16_t block[6][64])
1293 {
1294     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1295     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
1296     int16_t *mot_val;
1297     static int8_t quant_tab[4] = { -1, -2, 1, 2 };
1298     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1299
1300     av_assert2(s->h263_pred);
1301
1302     if (s->pict_type == AV_PICTURE_TYPE_P ||
1303         s->pict_type == AV_PICTURE_TYPE_S) {
1304         do {
1305             if (get_bits1(&s->gb)) {
1306                 /* skip mb */
1307                 s->mb_intra = 0;
1308                 for (i = 0; i < 6; i++)
1309                     s->block_last_index[i] = -1;
1310                 s->mv_dir  = MV_DIR_FORWARD;
1311                 s->mv_type = MV_TYPE_16X16;
1312                 if (s->pict_type == AV_PICTURE_TYPE_S &&
1313                     ctx->vol_sprite_usage == GMC_SPRITE) {
1314                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1315                                                      MB_TYPE_GMC   |
1316                                                      MB_TYPE_16x16 |
1317                                                      MB_TYPE_L0;
1318                     s->mcsel       = 1;
1319                     s->mv[0][0][0] = get_amv(ctx, 0);
1320                     s->mv[0][0][1] = get_amv(ctx, 1);
1321                     s->mb_skipped  = 0;
1322                 } else {
1323                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1324                                                      MB_TYPE_16x16 |
1325                                                      MB_TYPE_L0;
1326                     s->mcsel       = 0;
1327                     s->mv[0][0][0] = 0;
1328                     s->mv[0][0][1] = 0;
1329                     s->mb_skipped  = 1;
1330                 }
1331                 goto end;
1332             }
1333             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
1334             if (cbpc < 0) {
1335                 av_log(s->avctx, AV_LOG_ERROR,
1336                        "mcbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1337                 return -1;
1338             }
1339         } while (cbpc == 20);
1340
1341         s->dsp.clear_blocks(s->block[0]);
1342         dquant      = cbpc & 8;
1343         s->mb_intra = ((cbpc & 4) != 0);
1344         if (s->mb_intra)
1345             goto intra;
1346
1347         if (s->pict_type == AV_PICTURE_TYPE_S &&
1348             ctx->vol_sprite_usage == GMC_SPRITE && (cbpc & 16) == 0)
1349             s->mcsel = get_bits1(&s->gb);
1350         else
1351             s->mcsel = 0;
1352         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1) ^ 0x0F;
1353
1354         cbp = (cbpc & 3) | (cbpy << 2);
1355         if (dquant)
1356             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1357         if ((!s->progressive_sequence) &&
1358             (cbp || (s->workaround_bugs & FF_BUG_XVID_ILACE)))
1359             s->interlaced_dct = get_bits1(&s->gb);
1360
1361         s->mv_dir = MV_DIR_FORWARD;
1362         if ((cbpc & 16) == 0) {
1363             if (s->mcsel) {
1364                 s->current_picture.mb_type[xy] = MB_TYPE_GMC   |
1365                                                  MB_TYPE_16x16 |
1366                                                  MB_TYPE_L0;
1367                 /* 16x16 global motion prediction */
1368                 s->mv_type     = MV_TYPE_16X16;
1369                 mx             = get_amv(ctx, 0);
1370                 my             = get_amv(ctx, 1);
1371                 s->mv[0][0][0] = mx;
1372                 s->mv[0][0][1] = my;
1373             } else if ((!s->progressive_sequence) && get_bits1(&s->gb)) {
1374                 s->current_picture.mb_type[xy] = MB_TYPE_16x8 |
1375                                                  MB_TYPE_L0   |
1376                                                  MB_TYPE_INTERLACED;
1377                 /* 16x8 field motion prediction */
1378                 s->mv_type = MV_TYPE_FIELD;
1379
1380                 s->field_select[0][0] = get_bits1(&s->gb);
1381                 s->field_select[0][1] = get_bits1(&s->gb);
1382
1383                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1384
1385                 for (i = 0; i < 2; i++) {
1386                     mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1387                     if (mx >= 0xffff)
1388                         return -1;
1389
1390                     my = ff_h263_decode_motion(s, pred_y / 2, s->f_code);
1391                     if (my >= 0xffff)
1392                         return -1;
1393
1394                     s->mv[0][i][0] = mx;
1395                     s->mv[0][i][1] = my;
1396                 }
1397             } else {
1398                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
1399                 /* 16x16 motion prediction */
1400                 s->mv_type = MV_TYPE_16X16;
1401                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1402                 mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1403
1404                 if (mx >= 0xffff)
1405                     return -1;
1406
1407                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1408
1409                 if (my >= 0xffff)
1410                     return -1;
1411                 s->mv[0][0][0] = mx;
1412                 s->mv[0][0][1] = my;
1413             }
1414         } else {
1415             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
1416             s->mv_type                     = MV_TYPE_8X8;
1417             for (i = 0; i < 4; i++) {
1418                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
1419                 mx      = ff_h263_decode_motion(s, pred_x, s->f_code);
1420                 if (mx >= 0xffff)
1421                     return -1;
1422
1423                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1424                 if (my >= 0xffff)
1425                     return -1;
1426                 s->mv[0][i][0] = mx;
1427                 s->mv[0][i][1] = my;
1428                 mot_val[0]     = mx;
1429                 mot_val[1]     = my;
1430             }
1431         }
1432     } else if (s->pict_type == AV_PICTURE_TYPE_B) {
1433         int modb1;   // first bit of modb
1434         int modb2;   // second bit of modb
1435         int mb_type;
1436
1437         s->mb_intra = 0;  // B-frames never contain intra blocks
1438         s->mcsel    = 0;  //      ...               true gmc blocks
1439
1440         if (s->mb_x == 0) {
1441             for (i = 0; i < 2; i++) {
1442                 s->last_mv[i][0][0] =
1443                 s->last_mv[i][0][1] =
1444                 s->last_mv[i][1][0] =
1445                 s->last_mv[i][1][1] = 0;
1446             }
1447
1448             ff_thread_await_progress(&s->next_picture_ptr->tf, s->mb_y, 0);
1449         }
1450
1451         /* if we skipped it in the future P Frame than skip it now too */
1452         s->mb_skipped = s->next_picture.mbskip_table[s->mb_y * s->mb_stride + s->mb_x];  // Note, skiptab=0 if last was GMC
1453
1454         if (s->mb_skipped) {
1455             /* skip mb */
1456             for (i = 0; i < 6; i++)
1457                 s->block_last_index[i] = -1;
1458
1459             s->mv_dir      = MV_DIR_FORWARD;
1460             s->mv_type     = MV_TYPE_16X16;
1461             s->mv[0][0][0] =
1462             s->mv[0][0][1] =
1463             s->mv[1][0][0] =
1464             s->mv[1][0][1] = 0;
1465             s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1466                                              MB_TYPE_16x16 |
1467                                              MB_TYPE_L0;
1468             goto end;
1469         }
1470
1471         modb1 = get_bits1(&s->gb);
1472         if (modb1) {
1473             // like MB_TYPE_B_DIRECT but no vectors coded
1474             mb_type = MB_TYPE_DIRECT2 | MB_TYPE_SKIP | MB_TYPE_L0L1;
1475             cbp     = 0;
1476         } else {
1477             modb2   = get_bits1(&s->gb);
1478             mb_type = get_vlc2(&s->gb, mb_type_b_vlc.table, MB_TYPE_B_VLC_BITS, 1);
1479             if (mb_type < 0) {
1480                 av_log(s->avctx, AV_LOG_ERROR, "illegal MB_type\n");
1481                 return -1;
1482             }
1483             mb_type = mb_type_b_map[mb_type];
1484             if (modb2) {
1485                 cbp = 0;
1486             } else {
1487                 s->dsp.clear_blocks(s->block[0]);
1488                 cbp = get_bits(&s->gb, 6);
1489             }
1490
1491             if ((!IS_DIRECT(mb_type)) && cbp) {
1492                 if (get_bits1(&s->gb))
1493                     ff_set_qscale(s, s->qscale + get_bits1(&s->gb) * 4 - 2);
1494             }
1495
1496             if (!s->progressive_sequence) {
1497                 if (cbp)
1498                     s->interlaced_dct = get_bits1(&s->gb);
1499
1500                 if (!IS_DIRECT(mb_type) && get_bits1(&s->gb)) {
1501                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
1502                     mb_type &= ~MB_TYPE_16x16;
1503
1504                     if (USES_LIST(mb_type, 0)) {
1505                         s->field_select[0][0] = get_bits1(&s->gb);
1506                         s->field_select[0][1] = get_bits1(&s->gb);
1507                     }
1508                     if (USES_LIST(mb_type, 1)) {
1509                         s->field_select[1][0] = get_bits1(&s->gb);
1510                         s->field_select[1][1] = get_bits1(&s->gb);
1511                     }
1512                 }
1513             }
1514
1515             s->mv_dir = 0;
1516             if ((mb_type & (MB_TYPE_DIRECT2 | MB_TYPE_INTERLACED)) == 0) {
1517                 s->mv_type = MV_TYPE_16X16;
1518
1519                 if (USES_LIST(mb_type, 0)) {
1520                     s->mv_dir = MV_DIR_FORWARD;
1521
1522                     mx = ff_h263_decode_motion(s, s->last_mv[0][0][0], s->f_code);
1523                     my = ff_h263_decode_motion(s, s->last_mv[0][0][1], s->f_code);
1524                     s->last_mv[0][1][0] =
1525                     s->last_mv[0][0][0] =
1526                     s->mv[0][0][0]      = mx;
1527                     s->last_mv[0][1][1] =
1528                     s->last_mv[0][0][1] =
1529                     s->mv[0][0][1]      = my;
1530                 }
1531
1532                 if (USES_LIST(mb_type, 1)) {
1533                     s->mv_dir |= MV_DIR_BACKWARD;
1534
1535                     mx = ff_h263_decode_motion(s, s->last_mv[1][0][0], s->b_code);
1536                     my = ff_h263_decode_motion(s, s->last_mv[1][0][1], s->b_code);
1537                     s->last_mv[1][1][0] =
1538                     s->last_mv[1][0][0] =
1539                     s->mv[1][0][0]      = mx;
1540                     s->last_mv[1][1][1] =
1541                     s->last_mv[1][0][1] =
1542                     s->mv[1][0][1]      = my;
1543                 }
1544             } else if (!IS_DIRECT(mb_type)) {
1545                 s->mv_type = MV_TYPE_FIELD;
1546
1547                 if (USES_LIST(mb_type, 0)) {
1548                     s->mv_dir = MV_DIR_FORWARD;
1549
1550                     for (i = 0; i < 2; i++) {
1551                         mx = ff_h263_decode_motion(s, s->last_mv[0][i][0], s->f_code);
1552                         my = ff_h263_decode_motion(s, s->last_mv[0][i][1] / 2, s->f_code);
1553                         s->last_mv[0][i][0] =
1554                         s->mv[0][i][0]      = mx;
1555                         s->last_mv[0][i][1] = (s->mv[0][i][1] = my) * 2;
1556                     }
1557                 }
1558
1559                 if (USES_LIST(mb_type, 1)) {
1560                     s->mv_dir |= MV_DIR_BACKWARD;
1561
1562                     for (i = 0; i < 2; i++) {
1563                         mx = ff_h263_decode_motion(s, s->last_mv[1][i][0], s->b_code);
1564                         my = ff_h263_decode_motion(s, s->last_mv[1][i][1] / 2, s->b_code);
1565                         s->last_mv[1][i][0] =
1566                         s->mv[1][i][0]      = mx;
1567                         s->last_mv[1][i][1] = (s->mv[1][i][1] = my) * 2;
1568                     }
1569                 }
1570             }
1571         }
1572
1573         if (IS_DIRECT(mb_type)) {
1574             if (IS_SKIP(mb_type)) {
1575                 mx =
1576                 my = 0;
1577             } else {
1578                 mx = ff_h263_decode_motion(s, 0, 1);
1579                 my = ff_h263_decode_motion(s, 0, 1);
1580             }
1581
1582             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
1583             mb_type  |= ff_mpeg4_set_direct_mv(s, mx, my);
1584         }
1585         s->current_picture.mb_type[xy] = mb_type;
1586     } else { /* I-Frame */
1587         do {
1588             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
1589             if (cbpc < 0) {
1590                 av_log(s->avctx, AV_LOG_ERROR,
1591                        "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1592                 return -1;
1593             }
1594         } while (cbpc == 8);
1595
1596         dquant = cbpc & 4;
1597         s->mb_intra = 1;
1598
1599 intra:
1600         s->ac_pred = get_bits1(&s->gb);
1601         if (s->ac_pred)
1602             s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
1603         else
1604             s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
1605
1606         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
1607         if (cbpy < 0) {
1608             av_log(s->avctx, AV_LOG_ERROR,
1609                    "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
1610             return -1;
1611         }
1612         cbp = (cbpc & 3) | (cbpy << 2);
1613
1614         ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1615
1616         if (dquant)
1617             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1618
1619         if (!s->progressive_sequence)
1620             s->interlaced_dct = get_bits1(&s->gb);
1621
1622         s->dsp.clear_blocks(s->block[0]);
1623         /* decode each block */
1624         for (i = 0; i < 6; i++) {
1625             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 1, 0) < 0)
1626                 return -1;
1627             cbp += cbp;
1628         }
1629         goto end;
1630     }
1631
1632     /* decode each block */
1633     for (i = 0; i < 6; i++) {
1634         if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 0, 0) < 0)
1635             return -1;
1636         cbp += cbp;
1637     }
1638
1639 end:
1640     /* per-MB end of slice check */
1641     if (s->codec_id == AV_CODEC_ID_MPEG4) {
1642         int next = mpeg4_is_resync(ctx);
1643         if (next) {
1644             if        (s->mb_x + s->mb_y*s->mb_width + 1 >  next && (s->avctx->err_recognition & AV_EF_AGGRESSIVE)) {
1645                 return -1;
1646             } else if (s->mb_x + s->mb_y*s->mb_width + 1 >= next)
1647                 return SLICE_END;
1648
1649             if (s->pict_type == AV_PICTURE_TYPE_B) {
1650                 const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
1651                 ff_thread_await_progress(&s->next_picture_ptr->tf,
1652                                          (s->mb_x + delta >= s->mb_width)
1653                                          ? FFMIN(s->mb_y + 1, s->mb_height - 1)
1654                                          : s->mb_y, 0);
1655                 if (s->next_picture.mbskip_table[xy + delta])
1656                     return SLICE_OK;
1657             }
1658
1659             return SLICE_END;
1660         }
1661     }
1662
1663     return SLICE_OK;
1664 }
1665
1666 static int mpeg4_decode_gop_header(MpegEncContext *s, GetBitContext *gb)
1667 {
1668     int hours, minutes, seconds;
1669
1670     if (!show_bits(gb, 23)) {
1671         av_log(s->avctx, AV_LOG_WARNING, "GOP header invalid\n");
1672         return -1;
1673     }
1674
1675     hours   = get_bits(gb, 5);
1676     minutes = get_bits(gb, 6);
1677     skip_bits1(gb);
1678     seconds = get_bits(gb, 6);
1679
1680     s->time_base = seconds + 60*(minutes + 60*hours);
1681
1682     skip_bits1(gb);
1683     skip_bits1(gb);
1684
1685     return 0;
1686 }
1687
1688 static int mpeg4_decode_profile_level(MpegEncContext *s, GetBitContext *gb)
1689 {
1690
1691     s->avctx->profile = get_bits(gb, 4);
1692     s->avctx->level   = get_bits(gb, 4);
1693
1694     // for Simple profile, level 0
1695     if (s->avctx->profile == 0 && s->avctx->level == 8) {
1696         s->avctx->level = 0;
1697     }
1698
1699     return 0;
1700 }
1701
1702 static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
1703 {
1704     MpegEncContext *s = &ctx->m;
1705     int width, height, vo_ver_id;
1706
1707     /* vol header */
1708     skip_bits(gb, 1);                   /* random access */
1709     s->vo_type = get_bits(gb, 8);
1710     if (get_bits1(gb) != 0) {           /* is_ol_id */
1711         vo_ver_id = get_bits(gb, 4);    /* vo_ver_id */
1712         skip_bits(gb, 3);               /* vo_priority */
1713     } else {
1714         vo_ver_id = 1;
1715     }
1716     s->aspect_ratio_info = get_bits(gb, 4);
1717     if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1718         s->avctx->sample_aspect_ratio.num = get_bits(gb, 8);  // par_width
1719         s->avctx->sample_aspect_ratio.den = get_bits(gb, 8);  // par_height
1720     } else {
1721         s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[s->aspect_ratio_info];
1722     }
1723
1724     if ((s->vol_control_parameters = get_bits1(gb))) { /* vol control parameter */
1725         int chroma_format = get_bits(gb, 2);
1726         if (chroma_format != CHROMA_420)
1727             av_log(s->avctx, AV_LOG_ERROR, "illegal chroma format\n");
1728
1729         s->low_delay = get_bits1(gb);
1730         if (get_bits1(gb)) {    /* vbv parameters */
1731             get_bits(gb, 15);   /* first_half_bitrate */
1732             skip_bits1(gb);     /* marker */
1733             get_bits(gb, 15);   /* latter_half_bitrate */
1734             skip_bits1(gb);     /* marker */
1735             get_bits(gb, 15);   /* first_half_vbv_buffer_size */
1736             skip_bits1(gb);     /* marker */
1737             get_bits(gb, 3);    /* latter_half_vbv_buffer_size */
1738             get_bits(gb, 11);   /* first_half_vbv_occupancy */
1739             skip_bits1(gb);     /* marker */
1740             get_bits(gb, 15);   /* latter_half_vbv_occupancy */
1741             skip_bits1(gb);     /* marker */
1742         }
1743     } else {
1744         /* is setting low delay flag only once the smartest thing to do?
1745          * low delay detection won't be overridden. */
1746         if (s->picture_number == 0)
1747             s->low_delay = 0;
1748     }
1749
1750     ctx->shape = get_bits(gb, 2); /* vol shape */
1751     if (ctx->shape != RECT_SHAPE)
1752         av_log(s->avctx, AV_LOG_ERROR, "only rectangular vol supported\n");
1753     if (ctx->shape == GRAY_SHAPE && vo_ver_id != 1) {
1754         av_log(s->avctx, AV_LOG_ERROR, "Gray shape not supported\n");
1755         skip_bits(gb, 4);  /* video_object_layer_shape_extension */
1756     }
1757
1758     check_marker(gb, "before time_increment_resolution");
1759
1760     s->avctx->time_base.den = get_bits(gb, 16);
1761     if (!s->avctx->time_base.den) {
1762         av_log(s->avctx, AV_LOG_ERROR, "time_base.den==0\n");
1763         s->avctx->time_base.num = 0;
1764         return -1;
1765     }
1766
1767     ctx->time_increment_bits = av_log2(s->avctx->time_base.den - 1) + 1;
1768     if (ctx->time_increment_bits < 1)
1769         ctx->time_increment_bits = 1;
1770
1771     check_marker(gb, "before fixed_vop_rate");
1772
1773     if (get_bits1(gb) != 0)     /* fixed_vop_rate  */
1774         s->avctx->time_base.num = get_bits(gb, ctx->time_increment_bits);
1775     else
1776         s->avctx->time_base.num = 1;
1777
1778     ctx->t_frame = 0;
1779
1780     if (ctx->shape != BIN_ONLY_SHAPE) {
1781         if (ctx->shape == RECT_SHAPE) {
1782             check_marker(gb, "before width");
1783             width = get_bits(gb, 13);
1784             check_marker(gb, "before height");
1785             height = get_bits(gb, 13);
1786             check_marker(gb, "after height");
1787             if (width && height &&  /* they should be non zero but who knows */
1788                 !(s->width && s->codec_tag == AV_RL32("MP4S"))) {
1789                 if (s->width && s->height &&
1790                     (s->width != width || s->height != height))
1791                     s->context_reinit = 1;
1792                 s->width  = width;
1793                 s->height = height;
1794             }
1795         }
1796
1797         s->progressive_sequence  =
1798         s->progressive_frame     = get_bits1(gb) ^ 1;
1799         s->interlaced_dct        = 0;
1800         if (!get_bits1(gb) && (s->avctx->debug & FF_DEBUG_PICT_INFO))
1801             av_log(s->avctx, AV_LOG_INFO,           /* OBMC Disable */
1802                    "MPEG4 OBMC not supported (very likely buggy encoder)\n");
1803         if (vo_ver_id == 1)
1804             ctx->vol_sprite_usage = get_bits1(gb);    /* vol_sprite_usage */
1805         else
1806             ctx->vol_sprite_usage = get_bits(gb, 2);  /* vol_sprite_usage */
1807
1808         if (ctx->vol_sprite_usage == STATIC_SPRITE)
1809             av_log(s->avctx, AV_LOG_ERROR, "Static Sprites not supported\n");
1810         if (ctx->vol_sprite_usage == STATIC_SPRITE ||
1811             ctx->vol_sprite_usage == GMC_SPRITE) {
1812             if (ctx->vol_sprite_usage == STATIC_SPRITE) {
1813                 skip_bits(gb, 13); // sprite_width
1814                 skip_bits1(gb); /* marker */
1815                 skip_bits(gb, 13); // sprite_height
1816                 skip_bits1(gb); /* marker */
1817                 skip_bits(gb, 13); // sprite_left
1818                 skip_bits1(gb); /* marker */
1819                 skip_bits(gb, 13); // sprite_top
1820                 skip_bits1(gb); /* marker */
1821             }
1822             ctx->num_sprite_warping_points = get_bits(gb, 6);
1823             if (ctx->num_sprite_warping_points > 3) {
1824                 av_log(s->avctx, AV_LOG_ERROR,
1825                        "%d sprite_warping_points\n",
1826                        ctx->num_sprite_warping_points);
1827                 ctx->num_sprite_warping_points = 0;
1828                 return -1;
1829             }
1830             s->sprite_warping_accuracy  = get_bits(gb, 2);
1831             ctx->sprite_brightness_change = get_bits1(gb);
1832             if (ctx->vol_sprite_usage == STATIC_SPRITE)
1833                 skip_bits1(gb); // low_latency_sprite
1834         }
1835         // FIXME sadct disable bit if verid!=1 && shape not rect
1836
1837         if (get_bits1(gb) == 1) {                   /* not_8_bit */
1838             s->quant_precision = get_bits(gb, 4);   /* quant_precision */
1839             if (get_bits(gb, 4) != 8)               /* bits_per_pixel */
1840                 av_log(s->avctx, AV_LOG_ERROR, "N-bit not supported\n");
1841             if (s->quant_precision != 5)
1842                 av_log(s->avctx, AV_LOG_ERROR,
1843                        "quant precision %d\n", s->quant_precision);
1844             if (s->quant_precision<3 || s->quant_precision>9) {
1845                 s->quant_precision = 5;
1846             }
1847         } else {
1848             s->quant_precision = 5;
1849         }
1850
1851         // FIXME a bunch of grayscale shape things
1852
1853         if ((s->mpeg_quant = get_bits1(gb))) { /* vol_quant_type */
1854             int i, v;
1855
1856             /* load default matrixes */
1857             for (i = 0; i < 64; i++) {
1858                 int j = s->dsp.idct_permutation[i];
1859                 v = ff_mpeg4_default_intra_matrix[i];
1860                 s->intra_matrix[j]        = v;
1861                 s->chroma_intra_matrix[j] = v;
1862
1863                 v = ff_mpeg4_default_non_intra_matrix[i];
1864                 s->inter_matrix[j]        = v;
1865                 s->chroma_inter_matrix[j] = v;
1866             }
1867
1868             /* load custom intra matrix */
1869             if (get_bits1(gb)) {
1870                 int last = 0;
1871                 for (i = 0; i < 64; i++) {
1872                     int j;
1873                     v = get_bits(gb, 8);
1874                     if (v == 0)
1875                         break;
1876
1877                     last = v;
1878                     j = s->dsp.idct_permutation[ff_zigzag_direct[i]];
1879                     s->intra_matrix[j]        = last;
1880                     s->chroma_intra_matrix[j] = last;
1881                 }
1882
1883                 /* replicate last value */
1884                 for (; i < 64; i++) {
1885                     int j = s->dsp.idct_permutation[ff_zigzag_direct[i]];
1886                     s->intra_matrix[j]        = last;
1887                     s->chroma_intra_matrix[j] = last;
1888                 }
1889             }
1890
1891             /* load custom non intra matrix */
1892             if (get_bits1(gb)) {
1893                 int last = 0;
1894                 for (i = 0; i < 64; i++) {
1895                     int j;
1896                     v = get_bits(gb, 8);
1897                     if (v == 0)
1898                         break;
1899
1900                     last = v;
1901                     j = s->dsp.idct_permutation[ff_zigzag_direct[i]];
1902                     s->inter_matrix[j]        = v;
1903                     s->chroma_inter_matrix[j] = v;
1904                 }
1905
1906                 /* replicate last value */
1907                 for (; i < 64; i++) {
1908                     int j = s->dsp.idct_permutation[ff_zigzag_direct[i]];
1909                     s->inter_matrix[j]        = last;
1910                     s->chroma_inter_matrix[j] = last;
1911                 }
1912             }
1913
1914             // FIXME a bunch of grayscale shape things
1915         }
1916
1917         if (vo_ver_id != 1)
1918             s->quarter_sample = get_bits1(gb);
1919         else
1920             s->quarter_sample = 0;
1921
1922         if (get_bits_left(gb) < 4) {
1923             av_log(s->avctx, AV_LOG_ERROR, "VOL Header truncated\n");
1924             return AVERROR_INVALIDDATA;
1925         }
1926
1927         if (!get_bits1(gb)) {
1928             int pos               = get_bits_count(gb);
1929             int estimation_method = get_bits(gb, 2);
1930             if (estimation_method < 2) {
1931                 if (!get_bits1(gb)) {
1932                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* opaque */
1933                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* transparent */
1934                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_cae */
1935                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* inter_cae */
1936                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* no_update */
1937                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* upampling */
1938                 }
1939                 if (!get_bits1(gb)) {
1940                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_blocks */
1941                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter_blocks */
1942                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter4v_blocks */
1943                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* not coded blocks */
1944                 }
1945                 if (!check_marker(gb, "in complexity estimation part 1")) {
1946                     skip_bits_long(gb, pos - get_bits_count(gb));
1947                     goto no_cplx_est;
1948                 }
1949                 if (!get_bits1(gb)) {
1950                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_coeffs */
1951                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_lines */
1952                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* vlc_syms */
1953                     ctx->cplx_estimation_trash_i += 4 * get_bits1(gb);  /* vlc_bits */
1954                 }
1955                 if (!get_bits1(gb)) {
1956                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* apm */
1957                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* npm */
1958                     ctx->cplx_estimation_trash_b += 8 * get_bits1(gb);  /* interpolate_mc_q */
1959                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* forwback_mc_q */
1960                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel2 */
1961                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel4 */
1962                 }
1963                 if (!check_marker(gb, "in complexity estimation part 2")) {
1964                     skip_bits_long(gb, pos - get_bits_count(gb));
1965                     goto no_cplx_est;
1966                 }
1967                 if (estimation_method == 1) {
1968                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* sadct */
1969                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* qpel */
1970                 }
1971             } else
1972                 av_log(s->avctx, AV_LOG_ERROR,
1973                        "Invalid Complexity estimation method %d\n",
1974                        estimation_method);
1975         } else {
1976
1977 no_cplx_est:
1978             ctx->cplx_estimation_trash_i =
1979             ctx->cplx_estimation_trash_p =
1980             ctx->cplx_estimation_trash_b = 0;
1981         }
1982
1983         ctx->resync_marker = !get_bits1(gb); /* resync_marker_disabled */
1984
1985         s->data_partitioning = get_bits1(gb);
1986         if (s->data_partitioning)
1987             ctx->rvlc = get_bits1(gb);
1988
1989         if (vo_ver_id != 1) {
1990             ctx->new_pred = get_bits1(gb);
1991             if (ctx->new_pred) {
1992                 av_log(s->avctx, AV_LOG_ERROR, "new pred not supported\n");
1993                 skip_bits(gb, 2); /* requested upstream message type */
1994                 skip_bits1(gb);   /* newpred segment type */
1995             }
1996             if (get_bits1(gb)) // reduced_res_vop
1997                 av_log(s->avctx, AV_LOG_ERROR,
1998                        "reduced resolution VOP not supported\n");
1999         } else {
2000             ctx->new_pred = 0;
2001         }
2002
2003         ctx->scalability = get_bits1(gb);
2004
2005         if (ctx->scalability) {
2006             GetBitContext bak = *gb;
2007             int h_sampling_factor_n;
2008             int h_sampling_factor_m;
2009             int v_sampling_factor_n;
2010             int v_sampling_factor_m;
2011
2012             skip_bits1(gb);    // hierarchy_type
2013             skip_bits(gb, 4);  /* ref_layer_id */
2014             skip_bits1(gb);    /* ref_layer_sampling_dir */
2015             h_sampling_factor_n = get_bits(gb, 5);
2016             h_sampling_factor_m = get_bits(gb, 5);
2017             v_sampling_factor_n = get_bits(gb, 5);
2018             v_sampling_factor_m = get_bits(gb, 5);
2019             ctx->enhancement_type = get_bits1(gb);
2020
2021             if (h_sampling_factor_n == 0 || h_sampling_factor_m == 0 ||
2022                 v_sampling_factor_n == 0 || v_sampling_factor_m == 0) {
2023                 /* illegal scalability header (VERY broken encoder),
2024                  * trying to workaround */
2025                 ctx->scalability = 0;
2026                 *gb            = bak;
2027             } else
2028                 av_log(s->avctx, AV_LOG_ERROR, "scalability not supported\n");
2029
2030             // bin shape stuff FIXME
2031         }
2032     }
2033
2034     if (s->avctx->debug&FF_DEBUG_PICT_INFO) {
2035         av_log(s->avctx, AV_LOG_DEBUG, "tb %d/%d, tincrbits:%d, qp_prec:%d, ps:%d,  %s%s%s%s\n",
2036                s->avctx->time_base.num, s->avctx->time_base.den,
2037                ctx->time_increment_bits,
2038                s->quant_precision,
2039                s->progressive_sequence,
2040                ctx->scalability ? "scalability " :"" , s->quarter_sample ? "qpel " : "",
2041                s->data_partitioning ? "partition " : "", ctx->rvlc ? "rvlc " : ""
2042         );
2043     }
2044
2045     return 0;
2046 }
2047
2048 /**
2049  * Decode the user data stuff in the header.
2050  * Also initializes divx/xvid/lavc_version/build.
2051  */
2052 static int decode_user_data(Mpeg4DecContext *ctx, GetBitContext *gb)
2053 {
2054     MpegEncContext *s = &ctx->m;
2055     char buf[256];
2056     int i;
2057     int e;
2058     int ver = 0, build = 0, ver2 = 0, ver3 = 0;
2059     char last;
2060
2061     for (i = 0; i < 255 && get_bits_count(gb) < gb->size_in_bits; i++) {
2062         if (show_bits(gb, 23) == 0)
2063             break;
2064         buf[i] = get_bits(gb, 8);
2065     }
2066     buf[i] = 0;
2067
2068     /* divx detection */
2069     e = sscanf(buf, "DivX%dBuild%d%c", &ver, &build, &last);
2070     if (e < 2)
2071         e = sscanf(buf, "DivX%db%d%c", &ver, &build, &last);
2072     if (e >= 2) {
2073         ctx->divx_version = ver;
2074         ctx->divx_build   = build;
2075         s->divx_packed  = e == 3 && last == 'p';
2076         if (s->divx_packed && !ctx->showed_packed_warning) {
2077             av_log(s->avctx, AV_LOG_INFO, "Video uses a non-standard and "
2078                    "wasteful way to store B-frames ('packed B-frames'). "
2079                    "Consider using a tool like VirtualDub or avidemux to fix it.\n");
2080             ctx->showed_packed_warning = 1;
2081         }
2082     }
2083
2084     /* libavcodec detection */
2085     e = sscanf(buf, "FFmpe%*[^b]b%d", &build) + 3;
2086     if (e != 4)
2087         e = sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build);
2088     if (e != 4) {
2089         e = sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3) + 1;
2090         if (e > 1)
2091             build = (ver << 16) + (ver2 << 8) + ver3;
2092     }
2093     if (e != 4) {
2094         if (strcmp(buf, "ffmpeg") == 0)
2095             ctx->lavc_build = 4600;
2096     }
2097     if (e == 4)
2098         ctx->lavc_build = build;
2099
2100     /* Xvid detection */
2101     e = sscanf(buf, "XviD%d", &build);
2102     if (e == 1)
2103         ctx->xvid_build = build;
2104
2105     return 0;
2106 }
2107
2108 int ff_mpeg4_workaround_bugs(AVCodecContext *avctx)
2109 {
2110     Mpeg4DecContext *ctx = avctx->priv_data;
2111     MpegEncContext *s = &ctx->m;
2112
2113     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1) {
2114         if (s->stream_codec_tag == AV_RL32("XVID") ||
2115             s->codec_tag        == AV_RL32("XVID") ||
2116             s->codec_tag        == AV_RL32("XVIX") ||
2117             s->codec_tag        == AV_RL32("RMP4") ||
2118             s->codec_tag        == AV_RL32("ZMP4") ||
2119             s->codec_tag        == AV_RL32("SIPP"))
2120             ctx->xvid_build = 0;
2121     }
2122
2123     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1)
2124         if (s->codec_tag == AV_RL32("DIVX") && s->vo_type == 0 &&
2125             s->vol_control_parameters == 0)
2126             ctx->divx_version = 400;  // divx 4
2127
2128     if (ctx->xvid_build >= 0 && ctx->divx_version >= 0) {
2129         ctx->divx_version =
2130         ctx->divx_build   = -1;
2131     }
2132
2133     if (s->workaround_bugs & FF_BUG_AUTODETECT) {
2134         if (s->codec_tag == AV_RL32("XVIX"))
2135             s->workaround_bugs |= FF_BUG_XVID_ILACE;
2136
2137         if (s->codec_tag == AV_RL32("UMP4"))
2138             s->workaround_bugs |= FF_BUG_UMP4;
2139
2140         if (ctx->divx_version >= 500 && ctx->divx_build < 1814)
2141             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2142
2143         if (ctx->divx_version > 502 && ctx->divx_build < 1814)
2144             s->workaround_bugs |= FF_BUG_QPEL_CHROMA2;
2145
2146         if (ctx->xvid_build <= 3U)
2147             s->padding_bug_score = 256 * 256 * 256 * 64;
2148
2149         if (ctx->xvid_build <= 1U)
2150             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2151
2152         if (ctx->xvid_build <= 12U)
2153             s->workaround_bugs |= FF_BUG_EDGE;
2154
2155         if (ctx->xvid_build <= 32U)
2156             s->workaround_bugs |= FF_BUG_DC_CLIP;
2157
2158 #define SET_QPEL_FUNC(postfix1, postfix2)                           \
2159     s->dsp.put_        ## postfix1 = ff_put_        ## postfix2;    \
2160     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;    \
2161     s->dsp.avg_        ## postfix1 = ff_avg_        ## postfix2;
2162
2163         if (ctx->lavc_build < 4653U)
2164             s->workaround_bugs |= FF_BUG_STD_QPEL;
2165
2166         if (ctx->lavc_build < 4655U)
2167             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2168
2169         if (ctx->lavc_build < 4670U)
2170             s->workaround_bugs |= FF_BUG_EDGE;
2171
2172         if (ctx->lavc_build <= 4712U)
2173             s->workaround_bugs |= FF_BUG_DC_CLIP;
2174
2175         if (ctx->divx_version >= 0)
2176             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2177         if (ctx->divx_version == 501 && ctx->divx_build == 20020416)
2178             s->padding_bug_score = 256 * 256 * 256 * 64;
2179
2180         if (ctx->divx_version < 500U)
2181             s->workaround_bugs |= FF_BUG_EDGE;
2182
2183         if (ctx->divx_version >= 0)
2184             s->workaround_bugs |= FF_BUG_HPEL_CHROMA;
2185     }
2186
2187     if (s->workaround_bugs & FF_BUG_STD_QPEL) {
2188         SET_QPEL_FUNC(qpel_pixels_tab[0][5], qpel16_mc11_old_c)
2189         SET_QPEL_FUNC(qpel_pixels_tab[0][7], qpel16_mc31_old_c)
2190         SET_QPEL_FUNC(qpel_pixels_tab[0][9], qpel16_mc12_old_c)
2191         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
2192         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
2193         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
2194
2195         SET_QPEL_FUNC(qpel_pixels_tab[1][5], qpel8_mc11_old_c)
2196         SET_QPEL_FUNC(qpel_pixels_tab[1][7], qpel8_mc31_old_c)
2197         SET_QPEL_FUNC(qpel_pixels_tab[1][9], qpel8_mc12_old_c)
2198         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
2199         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
2200         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
2201     }
2202
2203     if (avctx->debug & FF_DEBUG_BUGS)
2204         av_log(s->avctx, AV_LOG_DEBUG,
2205                "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
2206                s->workaround_bugs, ctx->lavc_build, ctx->xvid_build,
2207                ctx->divx_version, ctx->divx_build, s->divx_packed ? "p" : "");
2208
2209 #if HAVE_MMX
2210     if (s->codec_id == AV_CODEC_ID_MPEG4 && ctx->xvid_build >= 0 &&
2211         avctx->idct_algo == FF_IDCT_AUTO &&
2212         (av_get_cpu_flags() & AV_CPU_FLAG_MMX)) {
2213         avctx->idct_algo = FF_IDCT_XVIDMMX;
2214         ff_dct_common_init(s);
2215         return 1;
2216     }
2217 #endif
2218     return 0;
2219 }
2220
2221 static int decode_vop_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2222 {
2223     MpegEncContext *s = &ctx->m;
2224     int time_incr, time_increment;
2225     int64_t pts;
2226
2227     s->pict_type = get_bits(gb, 2) + AV_PICTURE_TYPE_I;        /* pict type: I = 0 , P = 1 */
2228     if (s->pict_type == AV_PICTURE_TYPE_B && s->low_delay &&
2229         s->vol_control_parameters == 0 && !(s->flags & CODEC_FLAG_LOW_DELAY)) {
2230         av_log(s->avctx, AV_LOG_ERROR, "low_delay flag incorrectly, clearing it\n");
2231         s->low_delay = 0;
2232     }
2233
2234     s->partitioned_frame = s->data_partitioning && s->pict_type != AV_PICTURE_TYPE_B;
2235     if (s->partitioned_frame)
2236         s->decode_mb = mpeg4_decode_partitioned_mb;
2237     else
2238         s->decode_mb = mpeg4_decode_mb;
2239
2240     time_incr = 0;
2241     while (get_bits1(gb) != 0)
2242         time_incr++;
2243
2244     check_marker(gb, "before time_increment");
2245
2246     if (ctx->time_increment_bits == 0 ||
2247         !(show_bits(gb, ctx->time_increment_bits + 1) & 1)) {
2248         av_log(s->avctx, AV_LOG_ERROR,
2249                "hmm, seems the headers are not complete, trying to guess time_increment_bits\n");
2250
2251         for (ctx->time_increment_bits = 1;
2252              ctx->time_increment_bits < 16;
2253              ctx->time_increment_bits++) {
2254             if (s->pict_type == AV_PICTURE_TYPE_P ||
2255                 (s->pict_type == AV_PICTURE_TYPE_S &&
2256                  ctx->vol_sprite_usage == GMC_SPRITE)) {
2257                 if ((show_bits(gb, ctx->time_increment_bits + 6) & 0x37) == 0x30)
2258                     break;
2259             } else if ((show_bits(gb, ctx->time_increment_bits + 5) & 0x1F) == 0x18)
2260                 break;
2261         }
2262
2263         av_log(s->avctx, AV_LOG_ERROR,
2264                "my guess is %d bits ;)\n", ctx->time_increment_bits);
2265         if (s->avctx->time_base.den && 4*s->avctx->time_base.den < 1<<ctx->time_increment_bits) {
2266             s->avctx->time_base.den = 1<<ctx->time_increment_bits;
2267         }
2268     }
2269
2270     if (IS_3IV1)
2271         time_increment = get_bits1(gb);        // FIXME investigate further
2272     else
2273         time_increment = get_bits(gb, ctx->time_increment_bits);
2274
2275     if (s->pict_type != AV_PICTURE_TYPE_B) {
2276         s->last_time_base = s->time_base;
2277         s->time_base     += time_incr;
2278         s->time = s->time_base * s->avctx->time_base.den + time_increment;
2279         if (s->workaround_bugs & FF_BUG_UMP4) {
2280             if (s->time < s->last_non_b_time) {
2281                 /* header is not mpeg-4-compatible, broken encoder,
2282                  * trying to workaround */
2283                 s->time_base++;
2284                 s->time += s->avctx->time_base.den;
2285             }
2286         }
2287         s->pp_time         = s->time - s->last_non_b_time;
2288         s->last_non_b_time = s->time;
2289     } else {
2290         s->time    = (s->last_time_base + time_incr) * s->avctx->time_base.den + time_increment;
2291         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
2292         if (s->pp_time <= s->pb_time ||
2293             s->pp_time <= s->pp_time - s->pb_time ||
2294             s->pp_time <= 0) {
2295             /* messed up order, maybe after seeking? skipping current b-frame */
2296             return FRAME_SKIPPED;
2297         }
2298         ff_mpeg4_init_direct_mv(s);
2299
2300         if (ctx->t_frame == 0)
2301             ctx->t_frame = s->pb_time;
2302         if (ctx->t_frame == 0)
2303             ctx->t_frame = 1;  // 1/0 protection
2304         s->pp_field_time = (ROUNDED_DIV(s->last_non_b_time, ctx->t_frame) -
2305                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2306         s->pb_field_time = (ROUNDED_DIV(s->time, ctx->t_frame) -
2307                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2308         if (s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1) {
2309             s->pb_field_time = 2;
2310             s->pp_field_time = 4;
2311             if (!s->progressive_sequence)
2312                 return FRAME_SKIPPED;
2313         }
2314     }
2315
2316     if (s->avctx->time_base.num)
2317         pts = ROUNDED_DIV(s->time, s->avctx->time_base.num);
2318     else
2319         pts = AV_NOPTS_VALUE;
2320     if (s->avctx->debug&FF_DEBUG_PTS)
2321         av_log(s->avctx, AV_LOG_DEBUG, "MPEG4 PTS: %"PRId64"\n",
2322                pts);
2323
2324     check_marker(gb, "before vop_coded");
2325
2326     /* vop coded */
2327     if (get_bits1(gb) != 1) {
2328         if (s->avctx->debug & FF_DEBUG_PICT_INFO)
2329             av_log(s->avctx, AV_LOG_ERROR, "vop not coded\n");
2330         return FRAME_SKIPPED;
2331     }
2332     if (ctx->new_pred)
2333         decode_new_pred(ctx, gb);
2334
2335     if (ctx->shape != BIN_ONLY_SHAPE &&
2336                     (s->pict_type == AV_PICTURE_TYPE_P ||
2337                      (s->pict_type == AV_PICTURE_TYPE_S &&
2338                       ctx->vol_sprite_usage == GMC_SPRITE))) {
2339         /* rounding type for motion estimation */
2340         s->no_rounding = get_bits1(gb);
2341     } else {
2342         s->no_rounding = 0;
2343     }
2344     // FIXME reduced res stuff
2345
2346     if (ctx->shape != RECT_SHAPE) {
2347         if (ctx->vol_sprite_usage != 1 || s->pict_type != AV_PICTURE_TYPE_I) {
2348             skip_bits(gb, 13);  /* width */
2349             skip_bits1(gb);     /* marker */
2350             skip_bits(gb, 13);  /* height */
2351             skip_bits1(gb);     /* marker */
2352             skip_bits(gb, 13);  /* hor_spat_ref */
2353             skip_bits1(gb);     /* marker */
2354             skip_bits(gb, 13);  /* ver_spat_ref */
2355         }
2356         skip_bits1(gb);         /* change_CR_disable */
2357
2358         if (get_bits1(gb) != 0)
2359             skip_bits(gb, 8);   /* constant_alpha_value */
2360     }
2361
2362     // FIXME complexity estimation stuff
2363
2364     if (ctx->shape != BIN_ONLY_SHAPE) {
2365         skip_bits_long(gb, ctx->cplx_estimation_trash_i);
2366         if (s->pict_type != AV_PICTURE_TYPE_I)
2367             skip_bits_long(gb, ctx->cplx_estimation_trash_p);
2368         if (s->pict_type == AV_PICTURE_TYPE_B)
2369             skip_bits_long(gb, ctx->cplx_estimation_trash_b);
2370
2371         if (get_bits_left(gb) < 3) {
2372             av_log(s->avctx, AV_LOG_ERROR, "Header truncated\n");
2373             return -1;
2374         }
2375         ctx->intra_dc_threshold = ff_mpeg4_dc_threshold[get_bits(gb, 3)];
2376         if (!s->progressive_sequence) {
2377             s->top_field_first = get_bits1(gb);
2378             s->alternate_scan  = get_bits1(gb);
2379         } else
2380             s->alternate_scan = 0;
2381     }
2382
2383     if (s->alternate_scan) {
2384         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable,   ff_alternate_vertical_scan);
2385         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable,   ff_alternate_vertical_scan);
2386         ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
2387         ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2388     } else {
2389         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable,   ff_zigzag_direct);
2390         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable,   ff_zigzag_direct);
2391         ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
2392         ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2393     }
2394
2395     if (s->pict_type == AV_PICTURE_TYPE_S &&
2396         (ctx->vol_sprite_usage == STATIC_SPRITE ||
2397          ctx->vol_sprite_usage == GMC_SPRITE)) {
2398         if (mpeg4_decode_sprite_trajectory(ctx, gb) < 0)
2399             return AVERROR_INVALIDDATA;
2400         if (ctx->sprite_brightness_change)
2401             av_log(s->avctx, AV_LOG_ERROR,
2402                    "sprite_brightness_change not supported\n");
2403         if (ctx->vol_sprite_usage == STATIC_SPRITE)
2404             av_log(s->avctx, AV_LOG_ERROR, "static sprite not supported\n");
2405     }
2406
2407     if (ctx->shape != BIN_ONLY_SHAPE) {
2408         s->chroma_qscale = s->qscale = get_bits(gb, s->quant_precision);
2409         if (s->qscale == 0) {
2410             av_log(s->avctx, AV_LOG_ERROR,
2411                    "Error, header damaged or not MPEG4 header (qscale=0)\n");
2412             return -1;  // makes no sense to continue, as there is nothing left from the image then
2413         }
2414
2415         if (s->pict_type != AV_PICTURE_TYPE_I) {
2416             s->f_code = get_bits(gb, 3);        /* fcode_for */
2417             if (s->f_code == 0) {
2418                 av_log(s->avctx, AV_LOG_ERROR,
2419                        "Error, header damaged or not MPEG4 header (f_code=0)\n");
2420                 s->f_code = 1;
2421                 return -1;  // makes no sense to continue, as there is nothing left from the image then
2422             }
2423         } else
2424             s->f_code = 1;
2425
2426         if (s->pict_type == AV_PICTURE_TYPE_B) {
2427             s->b_code = get_bits(gb, 3);
2428             if (s->b_code == 0) {
2429                 av_log(s->avctx, AV_LOG_ERROR,
2430                        "Error, header damaged or not MPEG4 header (b_code=0)\n");
2431                 s->b_code=1;
2432                 return -1; // makes no sense to continue, as the MV decoding will break very quickly
2433             }
2434         } else
2435             s->b_code = 1;
2436
2437         if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
2438             av_log(s->avctx, AV_LOG_DEBUG,
2439                    "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 time:%"PRId64" tincr:%d\n",
2440                    s->qscale, s->f_code, s->b_code,
2441                    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")),
2442                    gb->size_in_bits,s->progressive_sequence, s->alternate_scan,
2443                    s->top_field_first, s->quarter_sample ? "q" : "h",
2444                    s->data_partitioning, ctx->resync_marker,
2445                    ctx->num_sprite_warping_points, s->sprite_warping_accuracy,
2446                    1 - s->no_rounding, s->vo_type,
2447                    s->vol_control_parameters ? " VOLC" : " ", ctx->intra_dc_threshold,
2448                    ctx->cplx_estimation_trash_i, ctx->cplx_estimation_trash_p,
2449                    ctx->cplx_estimation_trash_b,
2450                    s->time,
2451                    time_increment
2452                   );
2453         }
2454
2455         if (!ctx->scalability) {
2456             if (ctx->shape != RECT_SHAPE && s->pict_type != AV_PICTURE_TYPE_I)
2457                 skip_bits1(gb);  // vop shape coding type
2458         } else {
2459             if (ctx->enhancement_type) {
2460                 int load_backward_shape = get_bits1(gb);
2461                 if (load_backward_shape)
2462                     av_log(s->avctx, AV_LOG_ERROR,
2463                            "load backward shape isn't supported\n");
2464             }
2465             skip_bits(gb, 2);  // ref_select_code
2466         }
2467     }
2468     /* detect buggy encoders which don't set the low_delay flag
2469      * (divx4/xvid/opendivx). Note we cannot detect divx5 without b-frames
2470      * easily (although it's buggy too) */
2471     if (s->vo_type == 0 && s->vol_control_parameters == 0 &&
2472         ctx->divx_version == -1 && s->picture_number == 0) {
2473         av_log(s->avctx, AV_LOG_WARNING,
2474                "looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag\n");
2475         s->low_delay = 1;
2476     }
2477
2478     s->picture_number++;  // better than pic number==0 always ;)
2479
2480     // FIXME add short header support
2481     s->y_dc_scale_table = ff_mpeg4_y_dc_scale_table;
2482     s->c_dc_scale_table = ff_mpeg4_c_dc_scale_table;
2483
2484     if (s->workaround_bugs & FF_BUG_EDGE) {
2485         s->h_edge_pos = s->width;
2486         s->v_edge_pos = s->height;
2487     }
2488     return 0;
2489 }
2490
2491 /**
2492  * Decode mpeg4 headers.
2493  * @return <0 if no VOP found (or a damaged one)
2494  *         FRAME_SKIPPED if a not coded VOP is found
2495  *         0 if a VOP is found
2496  */
2497 int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2498 {
2499     MpegEncContext *s = &ctx->m;
2500     unsigned startcode, v;
2501
2502     /* search next start code */
2503     align_get_bits(gb);
2504
2505     if (s->codec_tag == AV_RL32("WV1F") && show_bits(gb, 24) == 0x575630) {
2506         skip_bits(gb, 24);
2507         if (get_bits(gb, 8) == 0xF0)
2508             goto end;
2509     }
2510
2511     startcode = 0xff;
2512     for (;;) {
2513         if (get_bits_count(gb) >= gb->size_in_bits) {
2514             if (gb->size_in_bits == 8 &&
2515                 (ctx->divx_version >= 0 || ctx->xvid_build >= 0) || s->codec_tag == AV_RL32("QMP4")) {
2516                 av_log(s->avctx, AV_LOG_VERBOSE, "frame skip %d\n", gb->size_in_bits);
2517                 return FRAME_SKIPPED;  // divx bug
2518             } else
2519                 return -1;  // end of stream
2520         }
2521
2522         /* use the bits after the test */
2523         v = get_bits(gb, 8);
2524         startcode = ((startcode << 8) | v) & 0xffffffff;
2525
2526         if ((startcode & 0xFFFFFF00) != 0x100)
2527             continue;  // no startcode
2528
2529         if (s->avctx->debug & FF_DEBUG_STARTCODE) {
2530             av_log(s->avctx, AV_LOG_DEBUG, "startcode: %3X ", startcode);
2531             if (startcode <= 0x11F)
2532                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Start");
2533             else if (startcode <= 0x12F)
2534                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Layer Start");
2535             else if (startcode <= 0x13F)
2536                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2537             else if (startcode <= 0x15F)
2538                 av_log(s->avctx, AV_LOG_DEBUG, "FGS bp start");
2539             else if (startcode <= 0x1AF)
2540                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2541             else if (startcode == 0x1B0)
2542                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq Start");
2543             else if (startcode == 0x1B1)
2544                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq End");
2545             else if (startcode == 0x1B2)
2546                 av_log(s->avctx, AV_LOG_DEBUG, "User Data");
2547             else if (startcode == 0x1B3)
2548                 av_log(s->avctx, AV_LOG_DEBUG, "Group of VOP start");
2549             else if (startcode == 0x1B4)
2550                 av_log(s->avctx, AV_LOG_DEBUG, "Video Session Error");
2551             else if (startcode == 0x1B5)
2552                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Start");
2553             else if (startcode == 0x1B6)
2554                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Plane start");
2555             else if (startcode == 0x1B7)
2556                 av_log(s->avctx, AV_LOG_DEBUG, "slice start");
2557             else if (startcode == 0x1B8)
2558                 av_log(s->avctx, AV_LOG_DEBUG, "extension start");
2559             else if (startcode == 0x1B9)
2560                 av_log(s->avctx, AV_LOG_DEBUG, "fgs start");
2561             else if (startcode == 0x1BA)
2562                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object start");
2563             else if (startcode == 0x1BB)
2564                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object Plane start");
2565             else if (startcode == 0x1BC)
2566                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object start");
2567             else if (startcode == 0x1BD)
2568                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object Plane start");
2569             else if (startcode == 0x1BE)
2570                 av_log(s->avctx, AV_LOG_DEBUG, "Still Texture Object start");
2571             else if (startcode == 0x1BF)
2572                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Spatial Layer start");
2573             else if (startcode == 0x1C0)
2574                 av_log(s->avctx, AV_LOG_DEBUG, "Texture SNR Layer start");
2575             else if (startcode == 0x1C1)
2576                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Tile start");
2577             else if (startcode == 0x1C2)
2578                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Shape Layer start");
2579             else if (startcode == 0x1C3)
2580                 av_log(s->avctx, AV_LOG_DEBUG, "stuffing start");
2581             else if (startcode <= 0x1C5)
2582                 av_log(s->avctx, AV_LOG_DEBUG, "reserved");
2583             else if (startcode <= 0x1FF)
2584                 av_log(s->avctx, AV_LOG_DEBUG, "System start");
2585             av_log(s->avctx, AV_LOG_DEBUG, " at %d\n", get_bits_count(gb));
2586         }
2587
2588         if (startcode >= 0x120 && startcode <= 0x12F) {
2589             if (decode_vol_header(ctx, gb) < 0)
2590                 return -1;
2591         } else if (startcode == USER_DATA_STARTCODE) {
2592             decode_user_data(ctx, gb);
2593         } else if (startcode == GOP_STARTCODE) {
2594             mpeg4_decode_gop_header(s, gb);
2595         } else if (startcode == VOS_STARTCODE) {
2596             mpeg4_decode_profile_level(s, gb);
2597         } else if (startcode == VOP_STARTCODE) {
2598             break;
2599         }
2600
2601         align_get_bits(gb);
2602         startcode = 0xff;
2603     }
2604
2605 end:
2606     if (s->flags & CODEC_FLAG_LOW_DELAY)
2607         s->low_delay = 1;
2608     s->avctx->has_b_frames = !s->low_delay;
2609
2610     return decode_vop_header(ctx, gb);
2611 }
2612
2613 av_cold void ff_mpeg4videodec_static_init(void) {
2614     static int done = 0;
2615
2616     if (!done) {
2617         ff_init_rl(&ff_mpeg4_rl_intra, ff_mpeg4_static_rl_table_store[0]);
2618         ff_init_rl(&ff_rvlc_rl_inter, ff_mpeg4_static_rl_table_store[1]);
2619         ff_init_rl(&ff_rvlc_rl_intra, ff_mpeg4_static_rl_table_store[2]);
2620         INIT_VLC_RL(ff_mpeg4_rl_intra, 554);
2621         INIT_VLC_RL(ff_rvlc_rl_inter, 1072);
2622         INIT_VLC_RL(ff_rvlc_rl_intra, 1072);
2623         INIT_VLC_STATIC(&dc_lum, DC_VLC_BITS, 10 /* 13 */,
2624                         &ff_mpeg4_DCtab_lum[0][1], 2, 1,
2625                         &ff_mpeg4_DCtab_lum[0][0], 2, 1, 512);
2626         INIT_VLC_STATIC(&dc_chrom, DC_VLC_BITS, 10 /* 13 */,
2627                         &ff_mpeg4_DCtab_chrom[0][1], 2, 1,
2628                         &ff_mpeg4_DCtab_chrom[0][0], 2, 1, 512);
2629         INIT_VLC_STATIC(&sprite_trajectory, SPRITE_TRAJ_VLC_BITS, 15,
2630                         &ff_sprite_trajectory_tab[0][1], 4, 2,
2631                         &ff_sprite_trajectory_tab[0][0], 4, 2, 128);
2632         INIT_VLC_STATIC(&mb_type_b_vlc, MB_TYPE_B_VLC_BITS, 4,
2633                         &ff_mb_type_b_tab[0][1], 2, 1,
2634                         &ff_mb_type_b_tab[0][0], 2, 1, 16);
2635         done = 1;
2636     }
2637 }
2638
2639 int ff_mpeg4_frame_end(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
2640 {
2641     Mpeg4DecContext *ctx = avctx->priv_data;
2642     MpegEncContext    *s = &ctx->m;
2643
2644     /* divx 5.01+ bitstream reorder stuff */
2645     /* Since this clobbers the input buffer and hwaccel codecs still need the
2646      * data during hwaccel->end_frame we should not do this any earlier */
2647     if (s->divx_packed) {
2648         int current_pos     = s->gb.buffer == s->bitstream_buffer ? 0 : (get_bits_count(&s->gb) >> 3);
2649         int startcode_found = 0;
2650
2651         if (buf_size - current_pos > 7) {
2652
2653             int i;
2654             for (i = current_pos; i < buf_size - 4; i++)
2655
2656                 if (buf[i]     == 0 &&
2657                     buf[i + 1] == 0 &&
2658                     buf[i + 2] == 1 &&
2659                     buf[i + 3] == 0xB6) {
2660                     startcode_found = !(buf[i + 4] & 0x40);
2661                     break;
2662                 }
2663         }
2664
2665         if (startcode_found) {
2666             av_fast_padded_malloc(&s->bitstream_buffer,
2667                            &s->allocated_bitstream_buffer_size,
2668                            buf_size - current_pos);
2669             if (!s->bitstream_buffer)
2670                 return AVERROR(ENOMEM);
2671             memcpy(s->bitstream_buffer, buf + current_pos,
2672                    buf_size - current_pos);
2673             s->bitstream_buffer_size = buf_size - current_pos;
2674         }
2675     }
2676
2677     return 0;
2678 }
2679
2680 static int mpeg4_update_thread_context(AVCodecContext *dst,
2681                                        const AVCodecContext *src)
2682 {
2683     Mpeg4DecContext *s = dst->priv_data;
2684     const Mpeg4DecContext *s1 = src->priv_data;
2685
2686     int ret = ff_mpeg_update_thread_context(dst, src);
2687
2688     if (ret < 0)
2689         return ret;
2690
2691     memcpy(((uint8_t*)s) + sizeof(MpegEncContext), ((uint8_t*)s1) + sizeof(MpegEncContext), sizeof(Mpeg4DecContext) - sizeof(MpegEncContext));
2692
2693     return 0;
2694 }
2695
2696 static av_cold int decode_init(AVCodecContext *avctx)
2697 {
2698     Mpeg4DecContext *ctx = avctx->priv_data;
2699     MpegEncContext *s = &ctx->m;
2700     int ret;
2701
2702     ctx->divx_version =
2703     ctx->divx_build   =
2704     ctx->xvid_build   =
2705     ctx->lavc_build   = -1;
2706
2707     if ((ret = ff_h263_decode_init(avctx)) < 0)
2708         return ret;
2709
2710     ff_mpeg4videodec_static_init();
2711
2712     s->h263_pred = 1;
2713     s->low_delay = 0; /* default, might be overridden in the vol header during header parsing */
2714     s->decode_mb = mpeg4_decode_mb;
2715     ctx->time_increment_bits = 4; /* default value for broken headers */
2716
2717     avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
2718     avctx->internal->allocate_progress = 1;
2719
2720     return 0;
2721 }
2722
2723 static const AVProfile mpeg4_video_profiles[] = {
2724     { FF_PROFILE_MPEG4_SIMPLE,                    "Simple Profile" },
2725     { FF_PROFILE_MPEG4_SIMPLE_SCALABLE,           "Simple Scalable Profile" },
2726     { FF_PROFILE_MPEG4_CORE,                      "Core Profile" },
2727     { FF_PROFILE_MPEG4_MAIN,                      "Main Profile" },
2728     { FF_PROFILE_MPEG4_N_BIT,                     "N-bit Profile" },
2729     { FF_PROFILE_MPEG4_SCALABLE_TEXTURE,          "Scalable Texture Profile" },
2730     { FF_PROFILE_MPEG4_SIMPLE_FACE_ANIMATION,     "Simple Face Animation Profile" },
2731     { FF_PROFILE_MPEG4_BASIC_ANIMATED_TEXTURE,    "Basic Animated Texture Profile" },
2732     { FF_PROFILE_MPEG4_HYBRID,                    "Hybrid Profile" },
2733     { FF_PROFILE_MPEG4_ADVANCED_REAL_TIME,        "Advanced Real Time Simple Profile" },
2734     { FF_PROFILE_MPEG4_CORE_SCALABLE,             "Code Scalable Profile" },
2735     { FF_PROFILE_MPEG4_ADVANCED_CODING,           "Advanced Coding Profile" },
2736     { FF_PROFILE_MPEG4_ADVANCED_CORE,             "Advanced Core Profile" },
2737     { FF_PROFILE_MPEG4_ADVANCED_SCALABLE_TEXTURE, "Advanced Scalable Texture Profile" },
2738     { FF_PROFILE_MPEG4_SIMPLE_STUDIO,             "Simple Studio Profile" },
2739     { FF_PROFILE_MPEG4_ADVANCED_SIMPLE,           "Advanced Simple Profile" },
2740     { FF_PROFILE_UNKNOWN },
2741 };
2742
2743 static const AVOption mpeg4_options[] = {
2744     {"quarter_sample", "1/4 subpel MC", offsetof(MpegEncContext, quarter_sample), FF_OPT_TYPE_INT, {.i64 = 0}, 0, 1, 0},
2745     {"divx_packed", "divx style packed b frames", offsetof(MpegEncContext, divx_packed), FF_OPT_TYPE_INT, {.i64 = 0}, 0, 1, 0},
2746     {NULL}
2747 };
2748
2749 static const AVClass mpeg4_class = {
2750     "MPEG4 Video Decoder",
2751     av_default_item_name,
2752     mpeg4_options,
2753     LIBAVUTIL_VERSION_INT,
2754 };
2755
2756 static const AVClass mpeg4_vdpau_class = {
2757     "MPEG4 Video VDPAU Decoder",
2758     av_default_item_name,
2759     mpeg4_options,
2760     LIBAVUTIL_VERSION_INT,
2761 };
2762
2763 AVCodec ff_mpeg4_decoder = {
2764     .name                  = "mpeg4",
2765     .long_name             = NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
2766     .type                  = AVMEDIA_TYPE_VIDEO,
2767     .id                    = AV_CODEC_ID_MPEG4,
2768     .priv_data_size        = sizeof(Mpeg4DecContext),
2769     .init                  = decode_init,
2770     .close                 = ff_h263_decode_end,
2771     .decode                = ff_h263_decode_frame,
2772     .capabilities          = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
2773                              CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
2774                              CODEC_CAP_FRAME_THREADS,
2775     .flush                 = ff_mpeg_flush,
2776     .max_lowres            = 3,
2777     .pix_fmts              = ff_h263_hwaccel_pixfmt_list_420,
2778     .profiles              = NULL_IF_CONFIG_SMALL(mpeg4_video_profiles),
2779     .update_thread_context = ONLY_IF_THREADS_ENABLED(mpeg4_update_thread_context),
2780     .priv_class = &mpeg4_class,
2781 };
2782
2783
2784 #if CONFIG_MPEG4_VDPAU_DECODER
2785 AVCodec ff_mpeg4_vdpau_decoder = {
2786     .name           = "mpeg4_vdpau",
2787     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 (VDPAU)"),
2788     .type           = AVMEDIA_TYPE_VIDEO,
2789     .id             = AV_CODEC_ID_MPEG4,
2790     .priv_data_size = sizeof(MpegEncContext),
2791     .init           = decode_init,
2792     .close          = ff_h263_decode_end,
2793     .decode         = ff_h263_decode_frame,
2794     .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
2795                       CODEC_CAP_HWACCEL_VDPAU,
2796     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_VDPAU_MPEG4,
2797                                                   AV_PIX_FMT_NONE },
2798     .priv_class     = &mpeg4_vdpau_class,
2799 };
2800 #endif