500068485786ce0bf508eb7f0a3bf434a349127c
[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                                "cbpc 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                            "cbpc 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                                     return -1;
1088                                 }
1089                                 SKIP_CACHE(re, &s->gb, 1);
1090
1091                                 level = SHOW_SBITS(re, &s->gb, 12);
1092                                 SKIP_CACHE(re, &s->gb, 12);
1093
1094                                 if (SHOW_UBITS(re, &s->gb, 1) == 0) {
1095                                     av_log(s->avctx, AV_LOG_ERROR,
1096                                            "2. marker bit missing in 3. esc\n");
1097                                     return -1;
1098                                 }
1099
1100                                 SKIP_COUNTER(re, &s->gb, 1 + 12 + 1);
1101                             }
1102
1103 #if 0
1104                             if (s->error_recognition >= FF_ER_COMPLIANT) {
1105                                 const int abs_level= FFABS(level);
1106                                 if (abs_level<=MAX_LEVEL && run<=MAX_RUN) {
1107                                     const int run1= run - rl->max_run[last][abs_level] - 1;
1108                                     if (abs_level <= rl->max_level[last][run]) {
1109                                         av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, vlc encoding possible\n");
1110                                         return -1;
1111                                     }
1112                                     if (s->error_recognition > FF_ER_COMPLIANT) {
1113                                         if (abs_level <= rl->max_level[last][run]*2) {
1114                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 1 encoding possible\n");
1115                                             return -1;
1116                                         }
1117                                         if (run1 >= 0 && abs_level <= rl->max_level[last][run1]) {
1118                                             av_log(s->avctx, AV_LOG_ERROR, "illegal 3. esc, esc 2 encoding possible\n");
1119                                             return -1;
1120                                         }
1121                                     }
1122                                 }
1123                             }
1124 #endif
1125                             if (level > 0)
1126                                 level = level * qmul + qadd;
1127                             else
1128                                 level = level * qmul - qadd;
1129
1130                             if ((unsigned)(level + 2048) > 4095) {
1131                                 if (s->err_recognition & (AV_EF_BITSTREAM|AV_EF_AGGRESSIVE)) {
1132                                     if (level > 2560 || level < -2560) {
1133                                         av_log(s->avctx, AV_LOG_ERROR,
1134                                                "|level| overflow in 3. esc, qp=%d\n",
1135                                                s->qscale);
1136                                         return -1;
1137                                     }
1138                                 }
1139                                 level = level < 0 ? -2048 : 2047;
1140                             }
1141
1142                             i += run + 1;
1143                             if (last)
1144                                 i += 192;
1145                         } else {
1146                             /* second escape */
1147                             SKIP_BITS(re, &s->gb, 2);
1148                             GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1149                             i    += run + rl->max_run[run >> 7][level / qmul] + 1;  // FIXME opt indexing
1150                             level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1151                             LAST_SKIP_BITS(re, &s->gb, 1);
1152                         }
1153                     } else {
1154                         /* first escape */
1155                         SKIP_BITS(re, &s->gb, 1);
1156                         GET_RL_VLC(level, run, re, &s->gb, rl_vlc, TEX_VLC_BITS, 2, 1);
1157                         i    += run;
1158                         level = level + rl->max_level[run >> 7][(run - 1) & 63] * qmul;  // FIXME opt indexing
1159                         level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1160                         LAST_SKIP_BITS(re, &s->gb, 1);
1161                     }
1162                 }
1163             } else {
1164                 i    += run;
1165                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
1166                 LAST_SKIP_BITS(re, &s->gb, 1);
1167             }
1168             if (i > 62) {
1169                 i -= 192;
1170                 if (i & (~63)) {
1171                     av_log(s->avctx, AV_LOG_ERROR,
1172                            "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
1173                     return -1;
1174                 }
1175
1176                 block[scan_table[i]] = level;
1177                 break;
1178             }
1179
1180             block[scan_table[i]] = level;
1181         }
1182         CLOSE_READER(re, &s->gb);
1183     }
1184
1185 not_coded:
1186     if (intra) {
1187         if (!ctx->use_intra_dc_vlc) {
1188             block[0] = ff_mpeg4_pred_dc(s, n, block[0], &dc_pred_dir, 0);
1189
1190             i -= i >> 31;  // if (i == -1) i = 0;
1191         }
1192
1193         ff_mpeg4_pred_ac(s, block, n, dc_pred_dir);
1194         if (s->ac_pred)
1195             i = 63;  // FIXME not optimal
1196     }
1197     s->block_last_index[n] = i;
1198     return 0;
1199 }
1200
1201 /**
1202  * decode partition C of one MB.
1203  * @return <0 if an error occurred
1204  */
1205 static int mpeg4_decode_partitioned_mb(MpegEncContext *s, int16_t block[6][64])
1206 {
1207     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1208     int cbp, mb_type;
1209     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1210
1211     mb_type = s->current_picture.mb_type[xy];
1212     cbp     = s->cbp_table[xy];
1213
1214     ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1215
1216     if (s->current_picture.qscale_table[xy] != s->qscale)
1217         ff_set_qscale(s, s->current_picture.qscale_table[xy]);
1218
1219     if (s->pict_type == AV_PICTURE_TYPE_P ||
1220         s->pict_type == AV_PICTURE_TYPE_S) {
1221         int i;
1222         for (i = 0; i < 4; i++) {
1223             s->mv[0][i][0] = s->current_picture.motion_val[0][s->block_index[i]][0];
1224             s->mv[0][i][1] = s->current_picture.motion_val[0][s->block_index[i]][1];
1225         }
1226         s->mb_intra = IS_INTRA(mb_type);
1227
1228         if (IS_SKIP(mb_type)) {
1229             /* skip mb */
1230             for (i = 0; i < 6; i++)
1231                 s->block_last_index[i] = -1;
1232             s->mv_dir  = MV_DIR_FORWARD;
1233             s->mv_type = MV_TYPE_16X16;
1234             if (s->pict_type == AV_PICTURE_TYPE_S
1235                 && ctx->vol_sprite_usage == GMC_SPRITE) {
1236                 s->mcsel      = 1;
1237                 s->mb_skipped = 0;
1238             } else {
1239                 s->mcsel      = 0;
1240                 s->mb_skipped = 1;
1241             }
1242         } else if (s->mb_intra) {
1243             s->ac_pred = IS_ACPRED(s->current_picture.mb_type[xy]);
1244         } else if (!s->mb_intra) {
1245             // s->mcsel = 0;  // FIXME do we need to init that?
1246
1247             s->mv_dir = MV_DIR_FORWARD;
1248             if (IS_8X8(mb_type)) {
1249                 s->mv_type = MV_TYPE_8X8;
1250             } else {
1251                 s->mv_type = MV_TYPE_16X16;
1252             }
1253         }
1254     } else { /* I-Frame */
1255         s->mb_intra = 1;
1256         s->ac_pred  = IS_ACPRED(s->current_picture.mb_type[xy]);
1257     }
1258
1259     if (!IS_SKIP(mb_type)) {
1260         int i;
1261         s->dsp.clear_blocks(s->block[0]);
1262         /* decode each block */
1263         for (i = 0; i < 6; i++) {
1264             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, s->mb_intra, ctx->rvlc) < 0) {
1265                 av_log(s->avctx, AV_LOG_ERROR,
1266                        "texture corrupted at %d %d %d\n",
1267                        s->mb_x, s->mb_y, s->mb_intra);
1268                 return -1;
1269             }
1270             cbp += cbp;
1271         }
1272     }
1273
1274     /* per-MB end of slice check */
1275     if (--s->mb_num_left <= 0) {
1276         if (mpeg4_is_resync(ctx))
1277             return SLICE_END;
1278         else
1279             return SLICE_NOEND;
1280     } else {
1281         if (mpeg4_is_resync(ctx)) {
1282             const int delta = s->mb_x + 1 == s->mb_width ? 2 : 1;
1283             if (s->cbp_table[xy + delta])
1284                 return SLICE_END;
1285         }
1286         return SLICE_OK;
1287     }
1288 }
1289
1290 static int mpeg4_decode_mb(MpegEncContext *s, int16_t block[6][64])
1291 {
1292     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
1293     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
1294     int16_t *mot_val;
1295     static int8_t quant_tab[4] = { -1, -2, 1, 2 };
1296     const int xy = s->mb_x + s->mb_y * s->mb_stride;
1297
1298     av_assert2(s->h263_pred);
1299
1300     if (s->pict_type == AV_PICTURE_TYPE_P ||
1301         s->pict_type == AV_PICTURE_TYPE_S) {
1302         do {
1303             if (get_bits1(&s->gb)) {
1304                 /* skip mb */
1305                 s->mb_intra = 0;
1306                 for (i = 0; i < 6; i++)
1307                     s->block_last_index[i] = -1;
1308                 s->mv_dir  = MV_DIR_FORWARD;
1309                 s->mv_type = MV_TYPE_16X16;
1310                 if (s->pict_type == AV_PICTURE_TYPE_S &&
1311                     ctx->vol_sprite_usage == GMC_SPRITE) {
1312                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1313                                                      MB_TYPE_GMC   |
1314                                                      MB_TYPE_16x16 |
1315                                                      MB_TYPE_L0;
1316                     s->mcsel       = 1;
1317                     s->mv[0][0][0] = get_amv(ctx, 0);
1318                     s->mv[0][0][1] = get_amv(ctx, 1);
1319                     s->mb_skipped  = 0;
1320                 } else {
1321                     s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1322                                                      MB_TYPE_16x16 |
1323                                                      MB_TYPE_L0;
1324                     s->mcsel       = 0;
1325                     s->mv[0][0][0] = 0;
1326                     s->mv[0][0][1] = 0;
1327                     s->mb_skipped  = 1;
1328                 }
1329                 goto end;
1330             }
1331             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
1332             if (cbpc < 0) {
1333                 av_log(s->avctx, AV_LOG_ERROR,
1334                        "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1335                 return -1;
1336             }
1337         } while (cbpc == 20);
1338
1339         s->dsp.clear_blocks(s->block[0]);
1340         dquant      = cbpc & 8;
1341         s->mb_intra = ((cbpc & 4) != 0);
1342         if (s->mb_intra)
1343             goto intra;
1344
1345         if (s->pict_type == AV_PICTURE_TYPE_S &&
1346             ctx->vol_sprite_usage == GMC_SPRITE && (cbpc & 16) == 0)
1347             s->mcsel = get_bits1(&s->gb);
1348         else
1349             s->mcsel = 0;
1350         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1) ^ 0x0F;
1351
1352         cbp = (cbpc & 3) | (cbpy << 2);
1353         if (dquant)
1354             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1355         if ((!s->progressive_sequence) &&
1356             (cbp || (s->workaround_bugs & FF_BUG_XVID_ILACE)))
1357             s->interlaced_dct = get_bits1(&s->gb);
1358
1359         s->mv_dir = MV_DIR_FORWARD;
1360         if ((cbpc & 16) == 0) {
1361             if (s->mcsel) {
1362                 s->current_picture.mb_type[xy] = MB_TYPE_GMC   |
1363                                                  MB_TYPE_16x16 |
1364                                                  MB_TYPE_L0;
1365                 /* 16x16 global motion prediction */
1366                 s->mv_type     = MV_TYPE_16X16;
1367                 mx             = get_amv(ctx, 0);
1368                 my             = get_amv(ctx, 1);
1369                 s->mv[0][0][0] = mx;
1370                 s->mv[0][0][1] = my;
1371             } else if ((!s->progressive_sequence) && get_bits1(&s->gb)) {
1372                 s->current_picture.mb_type[xy] = MB_TYPE_16x8 |
1373                                                  MB_TYPE_L0   |
1374                                                  MB_TYPE_INTERLACED;
1375                 /* 16x8 field motion prediction */
1376                 s->mv_type = MV_TYPE_FIELD;
1377
1378                 s->field_select[0][0] = get_bits1(&s->gb);
1379                 s->field_select[0][1] = get_bits1(&s->gb);
1380
1381                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1382
1383                 for (i = 0; i < 2; i++) {
1384                     mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1385                     if (mx >= 0xffff)
1386                         return -1;
1387
1388                     my = ff_h263_decode_motion(s, pred_y / 2, s->f_code);
1389                     if (my >= 0xffff)
1390                         return -1;
1391
1392                     s->mv[0][i][0] = mx;
1393                     s->mv[0][i][1] = my;
1394                 }
1395             } else {
1396                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
1397                 /* 16x16 motion prediction */
1398                 s->mv_type = MV_TYPE_16X16;
1399                 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
1400                 mx = ff_h263_decode_motion(s, pred_x, s->f_code);
1401
1402                 if (mx >= 0xffff)
1403                     return -1;
1404
1405                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1406
1407                 if (my >= 0xffff)
1408                     return -1;
1409                 s->mv[0][0][0] = mx;
1410                 s->mv[0][0][1] = my;
1411             }
1412         } else {
1413             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
1414             s->mv_type                     = MV_TYPE_8X8;
1415             for (i = 0; i < 4; i++) {
1416                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
1417                 mx      = ff_h263_decode_motion(s, pred_x, s->f_code);
1418                 if (mx >= 0xffff)
1419                     return -1;
1420
1421                 my = ff_h263_decode_motion(s, pred_y, s->f_code);
1422                 if (my >= 0xffff)
1423                     return -1;
1424                 s->mv[0][i][0] = mx;
1425                 s->mv[0][i][1] = my;
1426                 mot_val[0]     = mx;
1427                 mot_val[1]     = my;
1428             }
1429         }
1430     } else if (s->pict_type == AV_PICTURE_TYPE_B) {
1431         int modb1;   // first bit of modb
1432         int modb2;   // second bit of modb
1433         int mb_type;
1434
1435         s->mb_intra = 0;  // B-frames never contain intra blocks
1436         s->mcsel    = 0;  //      ...               true gmc blocks
1437
1438         if (s->mb_x == 0) {
1439             for (i = 0; i < 2; i++) {
1440                 s->last_mv[i][0][0] =
1441                 s->last_mv[i][0][1] =
1442                 s->last_mv[i][1][0] =
1443                 s->last_mv[i][1][1] = 0;
1444             }
1445
1446             ff_thread_await_progress(&s->next_picture_ptr->tf, s->mb_y, 0);
1447         }
1448
1449         /* if we skipped it in the future P Frame than skip it now too */
1450         s->mb_skipped = s->next_picture.mbskip_table[s->mb_y * s->mb_stride + s->mb_x];  // Note, skiptab=0 if last was GMC
1451
1452         if (s->mb_skipped) {
1453             /* skip mb */
1454             for (i = 0; i < 6; i++)
1455                 s->block_last_index[i] = -1;
1456
1457             s->mv_dir      = MV_DIR_FORWARD;
1458             s->mv_type     = MV_TYPE_16X16;
1459             s->mv[0][0][0] =
1460             s->mv[0][0][1] =
1461             s->mv[1][0][0] =
1462             s->mv[1][0][1] = 0;
1463             s->current_picture.mb_type[xy] = MB_TYPE_SKIP  |
1464                                              MB_TYPE_16x16 |
1465                                              MB_TYPE_L0;
1466             goto end;
1467         }
1468
1469         modb1 = get_bits1(&s->gb);
1470         if (modb1) {
1471             // like MB_TYPE_B_DIRECT but no vectors coded
1472             mb_type = MB_TYPE_DIRECT2 | MB_TYPE_SKIP | MB_TYPE_L0L1;
1473             cbp     = 0;
1474         } else {
1475             modb2   = get_bits1(&s->gb);
1476             mb_type = get_vlc2(&s->gb, mb_type_b_vlc.table, MB_TYPE_B_VLC_BITS, 1);
1477             if (mb_type < 0) {
1478                 av_log(s->avctx, AV_LOG_ERROR, "illegal MB_type\n");
1479                 return -1;
1480             }
1481             mb_type = mb_type_b_map[mb_type];
1482             if (modb2) {
1483                 cbp = 0;
1484             } else {
1485                 s->dsp.clear_blocks(s->block[0]);
1486                 cbp = get_bits(&s->gb, 6);
1487             }
1488
1489             if ((!IS_DIRECT(mb_type)) && cbp) {
1490                 if (get_bits1(&s->gb))
1491                     ff_set_qscale(s, s->qscale + get_bits1(&s->gb) * 4 - 2);
1492             }
1493
1494             if (!s->progressive_sequence) {
1495                 if (cbp)
1496                     s->interlaced_dct = get_bits1(&s->gb);
1497
1498                 if (!IS_DIRECT(mb_type) && get_bits1(&s->gb)) {
1499                     mb_type |= MB_TYPE_16x8 | MB_TYPE_INTERLACED;
1500                     mb_type &= ~MB_TYPE_16x16;
1501
1502                     if (USES_LIST(mb_type, 0)) {
1503                         s->field_select[0][0] = get_bits1(&s->gb);
1504                         s->field_select[0][1] = get_bits1(&s->gb);
1505                     }
1506                     if (USES_LIST(mb_type, 1)) {
1507                         s->field_select[1][0] = get_bits1(&s->gb);
1508                         s->field_select[1][1] = get_bits1(&s->gb);
1509                     }
1510                 }
1511             }
1512
1513             s->mv_dir = 0;
1514             if ((mb_type & (MB_TYPE_DIRECT2 | MB_TYPE_INTERLACED)) == 0) {
1515                 s->mv_type = MV_TYPE_16X16;
1516
1517                 if (USES_LIST(mb_type, 0)) {
1518                     s->mv_dir = MV_DIR_FORWARD;
1519
1520                     mx = ff_h263_decode_motion(s, s->last_mv[0][0][0], s->f_code);
1521                     my = ff_h263_decode_motion(s, s->last_mv[0][0][1], s->f_code);
1522                     s->last_mv[0][1][0] =
1523                     s->last_mv[0][0][0] =
1524                     s->mv[0][0][0]      = mx;
1525                     s->last_mv[0][1][1] =
1526                     s->last_mv[0][0][1] =
1527                     s->mv[0][0][1]      = my;
1528                 }
1529
1530                 if (USES_LIST(mb_type, 1)) {
1531                     s->mv_dir |= MV_DIR_BACKWARD;
1532
1533                     mx = ff_h263_decode_motion(s, s->last_mv[1][0][0], s->b_code);
1534                     my = ff_h263_decode_motion(s, s->last_mv[1][0][1], s->b_code);
1535                     s->last_mv[1][1][0] =
1536                     s->last_mv[1][0][0] =
1537                     s->mv[1][0][0]      = mx;
1538                     s->last_mv[1][1][1] =
1539                     s->last_mv[1][0][1] =
1540                     s->mv[1][0][1]      = my;
1541                 }
1542             } else if (!IS_DIRECT(mb_type)) {
1543                 s->mv_type = MV_TYPE_FIELD;
1544
1545                 if (USES_LIST(mb_type, 0)) {
1546                     s->mv_dir = MV_DIR_FORWARD;
1547
1548                     for (i = 0; i < 2; i++) {
1549                         mx = ff_h263_decode_motion(s, s->last_mv[0][i][0], s->f_code);
1550                         my = ff_h263_decode_motion(s, s->last_mv[0][i][1] / 2, s->f_code);
1551                         s->last_mv[0][i][0] =
1552                         s->mv[0][i][0]      = mx;
1553                         s->last_mv[0][i][1] = (s->mv[0][i][1] = my) * 2;
1554                     }
1555                 }
1556
1557                 if (USES_LIST(mb_type, 1)) {
1558                     s->mv_dir |= MV_DIR_BACKWARD;
1559
1560                     for (i = 0; i < 2; i++) {
1561                         mx = ff_h263_decode_motion(s, s->last_mv[1][i][0], s->b_code);
1562                         my = ff_h263_decode_motion(s, s->last_mv[1][i][1] / 2, s->b_code);
1563                         s->last_mv[1][i][0] =
1564                         s->mv[1][i][0]      = mx;
1565                         s->last_mv[1][i][1] = (s->mv[1][i][1] = my) * 2;
1566                     }
1567                 }
1568             }
1569         }
1570
1571         if (IS_DIRECT(mb_type)) {
1572             if (IS_SKIP(mb_type)) {
1573                 mx =
1574                 my = 0;
1575             } else {
1576                 mx = ff_h263_decode_motion(s, 0, 1);
1577                 my = ff_h263_decode_motion(s, 0, 1);
1578             }
1579
1580             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
1581             mb_type  |= ff_mpeg4_set_direct_mv(s, mx, my);
1582         }
1583         s->current_picture.mb_type[xy] = mb_type;
1584     } else { /* I-Frame */
1585         do {
1586             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
1587             if (cbpc < 0) {
1588                 av_log(s->avctx, AV_LOG_ERROR,
1589                        "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
1590                 return -1;
1591             }
1592         } while (cbpc == 8);
1593
1594         dquant = cbpc & 4;
1595         s->mb_intra = 1;
1596
1597 intra:
1598         s->ac_pred = get_bits1(&s->gb);
1599         if (s->ac_pred)
1600             s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
1601         else
1602             s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
1603
1604         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
1605         if (cbpy < 0) {
1606             av_log(s->avctx, AV_LOG_ERROR,
1607                    "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
1608             return -1;
1609         }
1610         cbp = (cbpc & 3) | (cbpy << 2);
1611
1612         ctx->use_intra_dc_vlc = s->qscale < ctx->intra_dc_threshold;
1613
1614         if (dquant)
1615             ff_set_qscale(s, s->qscale + quant_tab[get_bits(&s->gb, 2)]);
1616
1617         if (!s->progressive_sequence)
1618             s->interlaced_dct = get_bits1(&s->gb);
1619
1620         s->dsp.clear_blocks(s->block[0]);
1621         /* decode each block */
1622         for (i = 0; i < 6; i++) {
1623             if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 1, 0) < 0)
1624                 return -1;
1625             cbp += cbp;
1626         }
1627         goto end;
1628     }
1629
1630     /* decode each block */
1631     for (i = 0; i < 6; i++) {
1632         if (mpeg4_decode_block(ctx, block[i], i, cbp & 32, 0, 0) < 0)
1633             return -1;
1634         cbp += cbp;
1635     }
1636
1637 end:
1638     /* per-MB end of slice check */
1639     if (s->codec_id == AV_CODEC_ID_MPEG4) {
1640         int next = mpeg4_is_resync(ctx);
1641         if (next) {
1642             if        (s->mb_x + s->mb_y*s->mb_width + 1 >  next && (s->avctx->err_recognition & AV_EF_AGGRESSIVE)) {
1643                 return -1;
1644             } else if (s->mb_x + s->mb_y*s->mb_width + 1 >= next)
1645                 return SLICE_END;
1646
1647             if (s->pict_type == AV_PICTURE_TYPE_B) {
1648                 const int delta= s->mb_x + 1 == s->mb_width ? 2 : 1;
1649                 ff_thread_await_progress(&s->next_picture_ptr->tf,
1650                                          (s->mb_x + delta >= s->mb_width)
1651                                          ? FFMIN(s->mb_y + 1, s->mb_height - 1)
1652                                          : s->mb_y, 0);
1653                 if (s->next_picture.mbskip_table[xy + delta])
1654                     return SLICE_OK;
1655             }
1656
1657             return SLICE_END;
1658         }
1659     }
1660
1661     return SLICE_OK;
1662 }
1663
1664 static int mpeg4_decode_gop_header(MpegEncContext *s, GetBitContext *gb)
1665 {
1666     int hours, minutes, seconds;
1667
1668     if (!show_bits(gb, 23)) {
1669         av_log(s->avctx, AV_LOG_WARNING, "GOP header invalid\n");
1670         return -1;
1671     }
1672
1673     hours   = get_bits(gb, 5);
1674     minutes = get_bits(gb, 6);
1675     skip_bits1(gb);
1676     seconds = get_bits(gb, 6);
1677
1678     s->time_base = seconds + 60*(minutes + 60*hours);
1679
1680     skip_bits1(gb);
1681     skip_bits1(gb);
1682
1683     return 0;
1684 }
1685
1686 static int mpeg4_decode_profile_level(MpegEncContext *s, GetBitContext *gb)
1687 {
1688
1689     s->avctx->profile = get_bits(gb, 4);
1690     s->avctx->level   = get_bits(gb, 4);
1691
1692     // for Simple profile, level 0
1693     if (s->avctx->profile == 0 && s->avctx->level == 8) {
1694         s->avctx->level = 0;
1695     }
1696
1697     return 0;
1698 }
1699
1700 static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
1701 {
1702     MpegEncContext *s = &ctx->m;
1703     int width, height, vo_ver_id;
1704
1705     /* vol header */
1706     skip_bits(gb, 1);                   /* random access */
1707     s->vo_type = get_bits(gb, 8);
1708     if (get_bits1(gb) != 0) {           /* is_ol_id */
1709         vo_ver_id = get_bits(gb, 4);    /* vo_ver_id */
1710         skip_bits(gb, 3);               /* vo_priority */
1711     } else {
1712         vo_ver_id = 1;
1713     }
1714     s->aspect_ratio_info = get_bits(gb, 4);
1715     if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1716         s->avctx->sample_aspect_ratio.num = get_bits(gb, 8);  // par_width
1717         s->avctx->sample_aspect_ratio.den = get_bits(gb, 8);  // par_height
1718     } else {
1719         s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[s->aspect_ratio_info];
1720     }
1721
1722     if ((s->vol_control_parameters = get_bits1(gb))) { /* vol control parameter */
1723         int chroma_format = get_bits(gb, 2);
1724         if (chroma_format != CHROMA_420)
1725             av_log(s->avctx, AV_LOG_ERROR, "illegal chroma format\n");
1726
1727         s->low_delay = get_bits1(gb);
1728         if (get_bits1(gb)) {    /* vbv parameters */
1729             get_bits(gb, 15);   /* first_half_bitrate */
1730             skip_bits1(gb);     /* marker */
1731             get_bits(gb, 15);   /* latter_half_bitrate */
1732             skip_bits1(gb);     /* marker */
1733             get_bits(gb, 15);   /* first_half_vbv_buffer_size */
1734             skip_bits1(gb);     /* marker */
1735             get_bits(gb, 3);    /* latter_half_vbv_buffer_size */
1736             get_bits(gb, 11);   /* first_half_vbv_occupancy */
1737             skip_bits1(gb);     /* marker */
1738             get_bits(gb, 15);   /* latter_half_vbv_occupancy */
1739             skip_bits1(gb);     /* marker */
1740         }
1741     } else {
1742         /* is setting low delay flag only once the smartest thing to do?
1743          * low delay detection won't be overriden. */
1744         if (s->picture_number == 0)
1745             s->low_delay = 0;
1746     }
1747
1748     ctx->shape = get_bits(gb, 2); /* vol shape */
1749     if (ctx->shape != RECT_SHAPE)
1750         av_log(s->avctx, AV_LOG_ERROR, "only rectangular vol supported\n");
1751     if (ctx->shape == GRAY_SHAPE && vo_ver_id != 1) {
1752         av_log(s->avctx, AV_LOG_ERROR, "Gray shape not supported\n");
1753         skip_bits(gb, 4);  /* video_object_layer_shape_extension */
1754     }
1755
1756     check_marker(gb, "before time_increment_resolution");
1757
1758     s->avctx->time_base.den = get_bits(gb, 16);
1759     if (!s->avctx->time_base.den) {
1760         av_log(s->avctx, AV_LOG_ERROR, "time_base.den==0\n");
1761         s->avctx->time_base.num = 0;
1762         return -1;
1763     }
1764
1765     ctx->time_increment_bits = av_log2(s->avctx->time_base.den - 1) + 1;
1766     if (ctx->time_increment_bits < 1)
1767         ctx->time_increment_bits = 1;
1768
1769     check_marker(gb, "before fixed_vop_rate");
1770
1771     if (get_bits1(gb) != 0)     /* fixed_vop_rate  */
1772         s->avctx->time_base.num = get_bits(gb, ctx->time_increment_bits);
1773     else
1774         s->avctx->time_base.num = 1;
1775
1776     ctx->t_frame = 0;
1777
1778     if (ctx->shape != BIN_ONLY_SHAPE) {
1779         if (ctx->shape == RECT_SHAPE) {
1780             check_marker(gb, "before width");
1781             width = get_bits(gb, 13);
1782             check_marker(gb, "before height");
1783             height = get_bits(gb, 13);
1784             check_marker(gb, "after height");
1785             if (width && height &&  /* they should be non zero but who knows */
1786                 !(s->width && s->codec_tag == AV_RL32("MP4S"))) {
1787                 if (s->width && s->height &&
1788                     (s->width != width || s->height != height))
1789                     s->context_reinit = 1;
1790                 s->width  = width;
1791                 s->height = height;
1792             }
1793         }
1794
1795         s->progressive_sequence  =
1796         s->progressive_frame     = get_bits1(gb) ^ 1;
1797         s->interlaced_dct        = 0;
1798         if (!get_bits1(gb) && (s->avctx->debug & FF_DEBUG_PICT_INFO))
1799             av_log(s->avctx, AV_LOG_INFO,           /* OBMC Disable */
1800                    "MPEG4 OBMC not supported (very likely buggy encoder)\n");
1801         if (vo_ver_id == 1)
1802             ctx->vol_sprite_usage = get_bits1(gb);    /* vol_sprite_usage */
1803         else
1804             ctx->vol_sprite_usage = get_bits(gb, 2);  /* vol_sprite_usage */
1805
1806         if (ctx->vol_sprite_usage == STATIC_SPRITE)
1807             av_log(s->avctx, AV_LOG_ERROR, "Static Sprites not supported\n");
1808         if (ctx->vol_sprite_usage == STATIC_SPRITE ||
1809             ctx->vol_sprite_usage == GMC_SPRITE) {
1810             if (ctx->vol_sprite_usage == STATIC_SPRITE) {
1811                 skip_bits(gb, 13); // sprite_width
1812                 skip_bits1(gb); /* marker */
1813                 skip_bits(gb, 13); // sprite_height
1814                 skip_bits1(gb); /* marker */
1815                 skip_bits(gb, 13); // sprite_left
1816                 skip_bits1(gb); /* marker */
1817                 skip_bits(gb, 13); // sprite_top
1818                 skip_bits1(gb); /* marker */
1819             }
1820             ctx->num_sprite_warping_points = get_bits(gb, 6);
1821             if (ctx->num_sprite_warping_points > 3) {
1822                 av_log(s->avctx, AV_LOG_ERROR,
1823                        "%d sprite_warping_points\n",
1824                        ctx->num_sprite_warping_points);
1825                 ctx->num_sprite_warping_points = 0;
1826                 return -1;
1827             }
1828             s->sprite_warping_accuracy  = get_bits(gb, 2);
1829             ctx->sprite_brightness_change = get_bits1(gb);
1830             if (ctx->vol_sprite_usage == STATIC_SPRITE)
1831                 skip_bits1(gb); // low_latency_sprite
1832         }
1833         // FIXME sadct disable bit if verid!=1 && shape not rect
1834
1835         if (get_bits1(gb) == 1) {                   /* not_8_bit */
1836             s->quant_precision = get_bits(gb, 4);   /* quant_precision */
1837             if (get_bits(gb, 4) != 8)               /* bits_per_pixel */
1838                 av_log(s->avctx, AV_LOG_ERROR, "N-bit not supported\n");
1839             if (s->quant_precision != 5)
1840                 av_log(s->avctx, AV_LOG_ERROR,
1841                        "quant precision %d\n", s->quant_precision);
1842             if (s->quant_precision<3 || s->quant_precision>9) {
1843                 s->quant_precision = 5;
1844             }
1845         } else {
1846             s->quant_precision = 5;
1847         }
1848
1849         // FIXME a bunch of grayscale shape things
1850
1851         if ((s->mpeg_quant = get_bits1(gb))) { /* vol_quant_type */
1852             int i, v;
1853
1854             /* load default matrixes */
1855             for (i = 0; i < 64; i++) {
1856                 int j = s->dsp.idct_permutation[i];
1857                 v = ff_mpeg4_default_intra_matrix[i];
1858                 s->intra_matrix[j]        = v;
1859                 s->chroma_intra_matrix[j] = v;
1860
1861                 v = ff_mpeg4_default_non_intra_matrix[i];
1862                 s->inter_matrix[j]        = v;
1863                 s->chroma_inter_matrix[j] = v;
1864             }
1865
1866             /* load custom intra matrix */
1867             if (get_bits1(gb)) {
1868                 int last = 0;
1869                 for (i = 0; i < 64; i++) {
1870                     int j;
1871                     v = get_bits(gb, 8);
1872                     if (v == 0)
1873                         break;
1874
1875                     last = v;
1876                     j = s->dsp.idct_permutation[ff_zigzag_direct[i]];
1877                     s->intra_matrix[j]        = last;
1878                     s->chroma_intra_matrix[j] = last;
1879                 }
1880
1881                 /* replicate last value */
1882                 for (; i < 64; i++) {
1883                     int j = s->dsp.idct_permutation[ff_zigzag_direct[i]];
1884                     s->intra_matrix[j]        = last;
1885                     s->chroma_intra_matrix[j] = last;
1886                 }
1887             }
1888
1889             /* load custom non intra matrix */
1890             if (get_bits1(gb)) {
1891                 int last = 0;
1892                 for (i = 0; i < 64; i++) {
1893                     int j;
1894                     v = get_bits(gb, 8);
1895                     if (v == 0)
1896                         break;
1897
1898                     last = v;
1899                     j = s->dsp.idct_permutation[ff_zigzag_direct[i]];
1900                     s->inter_matrix[j]        = v;
1901                     s->chroma_inter_matrix[j] = v;
1902                 }
1903
1904                 /* replicate last value */
1905                 for (; i < 64; i++) {
1906                     int j = s->dsp.idct_permutation[ff_zigzag_direct[i]];
1907                     s->inter_matrix[j]        = last;
1908                     s->chroma_inter_matrix[j] = last;
1909                 }
1910             }
1911
1912             // FIXME a bunch of grayscale shape things
1913         }
1914
1915         if (vo_ver_id != 1)
1916             s->quarter_sample = get_bits1(gb);
1917         else
1918             s->quarter_sample = 0;
1919
1920         if (get_bits_left(gb) < 4) {
1921             av_log(s->avctx, AV_LOG_ERROR, "VOL Header truncated\n");
1922             return AVERROR_INVALIDDATA;
1923         }
1924
1925         if (!get_bits1(gb)) {
1926             int pos               = get_bits_count(gb);
1927             int estimation_method = get_bits(gb, 2);
1928             if (estimation_method < 2) {
1929                 if (!get_bits1(gb)) {
1930                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* opaque */
1931                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* transparent */
1932                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_cae */
1933                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* inter_cae */
1934                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* no_update */
1935                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* upampling */
1936                 }
1937                 if (!get_bits1(gb)) {
1938                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* intra_blocks */
1939                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter_blocks */
1940                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* inter4v_blocks */
1941                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* not coded blocks */
1942                 }
1943                 if (!check_marker(gb, "in complexity estimation part 1")) {
1944                     skip_bits_long(gb, pos - get_bits_count(gb));
1945                     goto no_cplx_est;
1946                 }
1947                 if (!get_bits1(gb)) {
1948                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_coeffs */
1949                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* dct_lines */
1950                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* vlc_syms */
1951                     ctx->cplx_estimation_trash_i += 4 * get_bits1(gb);  /* vlc_bits */
1952                 }
1953                 if (!get_bits1(gb)) {
1954                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* apm */
1955                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* npm */
1956                     ctx->cplx_estimation_trash_b += 8 * get_bits1(gb);  /* interpolate_mc_q */
1957                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* forwback_mc_q */
1958                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel2 */
1959                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* halfpel4 */
1960                 }
1961                 if (!check_marker(gb, "in complexity estimation part 2")) {
1962                     skip_bits_long(gb, pos - get_bits_count(gb));
1963                     goto no_cplx_est;
1964                 }
1965                 if (estimation_method == 1) {
1966                     ctx->cplx_estimation_trash_i += 8 * get_bits1(gb);  /* sadct */
1967                     ctx->cplx_estimation_trash_p += 8 * get_bits1(gb);  /* qpel */
1968                 }
1969             } else
1970                 av_log(s->avctx, AV_LOG_ERROR,
1971                        "Invalid Complexity estimation method %d\n",
1972                        estimation_method);
1973         } else {
1974
1975 no_cplx_est:
1976             ctx->cplx_estimation_trash_i =
1977             ctx->cplx_estimation_trash_p =
1978             ctx->cplx_estimation_trash_b = 0;
1979         }
1980
1981         ctx->resync_marker = !get_bits1(gb); /* resync_marker_disabled */
1982
1983         s->data_partitioning = get_bits1(gb);
1984         if (s->data_partitioning)
1985             ctx->rvlc = get_bits1(gb);
1986
1987         if (vo_ver_id != 1) {
1988             ctx->new_pred = get_bits1(gb);
1989             if (ctx->new_pred) {
1990                 av_log(s->avctx, AV_LOG_ERROR, "new pred not supported\n");
1991                 skip_bits(gb, 2); /* requested upstream message type */
1992                 skip_bits1(gb);   /* newpred segment type */
1993             }
1994             if (get_bits1(gb)) // reduced_res_vop
1995                 av_log(s->avctx, AV_LOG_ERROR,
1996                        "reduced resolution VOP not supported\n");
1997         } else {
1998             ctx->new_pred = 0;
1999         }
2000
2001         ctx->scalability = get_bits1(gb);
2002
2003         if (ctx->scalability) {
2004             GetBitContext bak = *gb;
2005             int h_sampling_factor_n;
2006             int h_sampling_factor_m;
2007             int v_sampling_factor_n;
2008             int v_sampling_factor_m;
2009
2010             skip_bits1(gb);    // hierarchy_type
2011             skip_bits(gb, 4);  /* ref_layer_id */
2012             skip_bits1(gb);    /* ref_layer_sampling_dir */
2013             h_sampling_factor_n = get_bits(gb, 5);
2014             h_sampling_factor_m = get_bits(gb, 5);
2015             v_sampling_factor_n = get_bits(gb, 5);
2016             v_sampling_factor_m = get_bits(gb, 5);
2017             ctx->enhancement_type = get_bits1(gb);
2018
2019             if (h_sampling_factor_n == 0 || h_sampling_factor_m == 0 ||
2020                 v_sampling_factor_n == 0 || v_sampling_factor_m == 0) {
2021                 /* illegal scalability header (VERY broken encoder),
2022                  * trying to workaround */
2023                 ctx->scalability = 0;
2024                 *gb            = bak;
2025             } else
2026                 av_log(s->avctx, AV_LOG_ERROR, "scalability not supported\n");
2027
2028             // bin shape stuff FIXME
2029         }
2030     }
2031
2032     if (s->avctx->debug&FF_DEBUG_PICT_INFO) {
2033         av_log(s->avctx, AV_LOG_DEBUG, "tb %d/%d, tincrbits:%d, qp_prec:%d, ps:%d,  %s%s%s%s\n",
2034                s->avctx->time_base.num, s->avctx->time_base.den,
2035                ctx->time_increment_bits,
2036                s->quant_precision,
2037                s->progressive_sequence,
2038                ctx->scalability ? "scalability " :"" , s->quarter_sample ? "qpel " : "",
2039                s->data_partitioning ? "partition " : "", ctx->rvlc ? "rvlc " : ""
2040         );
2041     }
2042
2043     return 0;
2044 }
2045
2046 /**
2047  * Decode the user data stuff in the header.
2048  * Also initializes divx/xvid/lavc_version/build.
2049  */
2050 static int decode_user_data(Mpeg4DecContext *ctx, GetBitContext *gb)
2051 {
2052     MpegEncContext *s = &ctx->m;
2053     char buf[256];
2054     int i;
2055     int e;
2056     int ver = 0, build = 0, ver2 = 0, ver3 = 0;
2057     char last;
2058
2059     for (i = 0; i < 255 && get_bits_count(gb) < gb->size_in_bits; i++) {
2060         if (show_bits(gb, 23) == 0)
2061             break;
2062         buf[i] = get_bits(gb, 8);
2063     }
2064     buf[i] = 0;
2065
2066     /* divx detection */
2067     e = sscanf(buf, "DivX%dBuild%d%c", &ver, &build, &last);
2068     if (e < 2)
2069         e = sscanf(buf, "DivX%db%d%c", &ver, &build, &last);
2070     if (e >= 2) {
2071         ctx->divx_version = ver;
2072         ctx->divx_build   = build;
2073         s->divx_packed  = e == 3 && last == 'p';
2074         if (s->divx_packed && !ctx->showed_packed_warning) {
2075             av_log(s->avctx, AV_LOG_INFO, "Video uses a non-standard and "
2076                    "wasteful way to store B-frames ('packed B-frames'). "
2077                    "Consider using a tool like VirtualDub or avidemux to fix it.\n");
2078             ctx->showed_packed_warning = 1;
2079         }
2080     }
2081
2082     /* libavcodec detection */
2083     e = sscanf(buf, "FFmpe%*[^b]b%d", &build) + 3;
2084     if (e != 4)
2085         e = sscanf(buf, "FFmpeg v%d.%d.%d / libavcodec build: %d", &ver, &ver2, &ver3, &build);
2086     if (e != 4) {
2087         e = sscanf(buf, "Lavc%d.%d.%d", &ver, &ver2, &ver3) + 1;
2088         if (e > 1)
2089             build = (ver << 16) + (ver2 << 8) + ver3;
2090     }
2091     if (e != 4) {
2092         if (strcmp(buf, "ffmpeg") == 0)
2093             ctx->lavc_build = 4600;
2094     }
2095     if (e == 4)
2096         ctx->lavc_build = build;
2097
2098     /* Xvid detection */
2099     e = sscanf(buf, "XviD%d", &build);
2100     if (e == 1)
2101         ctx->xvid_build = build;
2102
2103     return 0;
2104 }
2105
2106 int ff_mpeg4_workaround_bugs(AVCodecContext *avctx)
2107 {
2108     Mpeg4DecContext *ctx = avctx->priv_data;
2109     MpegEncContext *s = &ctx->m;
2110
2111     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1) {
2112         if (s->stream_codec_tag == AV_RL32("XVID") ||
2113             s->codec_tag        == AV_RL32("XVID") ||
2114             s->codec_tag        == AV_RL32("XVIX") ||
2115             s->codec_tag        == AV_RL32("RMP4") ||
2116             s->codec_tag        == AV_RL32("ZMP4") ||
2117             s->codec_tag        == AV_RL32("SIPP"))
2118             ctx->xvid_build = 0;
2119     }
2120
2121     if (ctx->xvid_build == -1 && ctx->divx_version == -1 && ctx->lavc_build == -1)
2122         if (s->codec_tag == AV_RL32("DIVX") && s->vo_type == 0 &&
2123             s->vol_control_parameters == 0)
2124             ctx->divx_version = 400;  // divx 4
2125
2126     if (ctx->xvid_build >= 0 && ctx->divx_version >= 0) {
2127         ctx->divx_version =
2128         ctx->divx_build   = -1;
2129     }
2130
2131     if (s->workaround_bugs & FF_BUG_AUTODETECT) {
2132         if (s->codec_tag == AV_RL32("XVIX"))
2133             s->workaround_bugs |= FF_BUG_XVID_ILACE;
2134
2135         if (s->codec_tag == AV_RL32("UMP4"))
2136             s->workaround_bugs |= FF_BUG_UMP4;
2137
2138         if (ctx->divx_version >= 500 && ctx->divx_build < 1814)
2139             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2140
2141         if (ctx->divx_version > 502 && ctx->divx_build < 1814)
2142             s->workaround_bugs |= FF_BUG_QPEL_CHROMA2;
2143
2144         if (ctx->xvid_build <= 3U)
2145             s->padding_bug_score = 256 * 256 * 256 * 64;
2146
2147         if (ctx->xvid_build <= 1U)
2148             s->workaround_bugs |= FF_BUG_QPEL_CHROMA;
2149
2150         if (ctx->xvid_build <= 12U)
2151             s->workaround_bugs |= FF_BUG_EDGE;
2152
2153         if (ctx->xvid_build <= 32U)
2154             s->workaround_bugs |= FF_BUG_DC_CLIP;
2155
2156 #define SET_QPEL_FUNC(postfix1, postfix2)                           \
2157     s->dsp.put_        ## postfix1 = ff_put_        ## postfix2;    \
2158     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;    \
2159     s->dsp.avg_        ## postfix1 = ff_avg_        ## postfix2;
2160
2161         if (ctx->lavc_build < 4653U)
2162             s->workaround_bugs |= FF_BUG_STD_QPEL;
2163
2164         if (ctx->lavc_build < 4655U)
2165             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2166
2167         if (ctx->lavc_build < 4670U)
2168             s->workaround_bugs |= FF_BUG_EDGE;
2169
2170         if (ctx->lavc_build <= 4712U)
2171             s->workaround_bugs |= FF_BUG_DC_CLIP;
2172
2173         if (ctx->divx_version >= 0)
2174             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
2175         if (ctx->divx_version == 501 && ctx->divx_build == 20020416)
2176             s->padding_bug_score = 256 * 256 * 256 * 64;
2177
2178         if (ctx->divx_version < 500U)
2179             s->workaround_bugs |= FF_BUG_EDGE;
2180
2181         if (ctx->divx_version >= 0)
2182             s->workaround_bugs |= FF_BUG_HPEL_CHROMA;
2183     }
2184
2185     if (s->workaround_bugs & FF_BUG_STD_QPEL) {
2186         SET_QPEL_FUNC(qpel_pixels_tab[0][5], qpel16_mc11_old_c)
2187         SET_QPEL_FUNC(qpel_pixels_tab[0][7], qpel16_mc31_old_c)
2188         SET_QPEL_FUNC(qpel_pixels_tab[0][9], qpel16_mc12_old_c)
2189         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
2190         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
2191         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
2192
2193         SET_QPEL_FUNC(qpel_pixels_tab[1][5], qpel8_mc11_old_c)
2194         SET_QPEL_FUNC(qpel_pixels_tab[1][7], qpel8_mc31_old_c)
2195         SET_QPEL_FUNC(qpel_pixels_tab[1][9], qpel8_mc12_old_c)
2196         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
2197         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
2198         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
2199     }
2200
2201     if (avctx->debug & FF_DEBUG_BUGS)
2202         av_log(s->avctx, AV_LOG_DEBUG,
2203                "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
2204                s->workaround_bugs, ctx->lavc_build, ctx->xvid_build,
2205                ctx->divx_version, ctx->divx_build, s->divx_packed ? "p" : "");
2206
2207 #if HAVE_MMX
2208     if (s->codec_id == AV_CODEC_ID_MPEG4 && ctx->xvid_build >= 0 &&
2209         avctx->idct_algo == FF_IDCT_AUTO &&
2210         (av_get_cpu_flags() & AV_CPU_FLAG_MMX)) {
2211         avctx->idct_algo = FF_IDCT_XVIDMMX;
2212         ff_dct_common_init(s);
2213         return 1;
2214     }
2215 #endif
2216     return 0;
2217 }
2218
2219 static int decode_vop_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2220 {
2221     MpegEncContext *s = &ctx->m;
2222     int time_incr, time_increment;
2223     int64_t pts;
2224
2225     s->pict_type = get_bits(gb, 2) + AV_PICTURE_TYPE_I;        /* pict type: I = 0 , P = 1 */
2226     if (s->pict_type == AV_PICTURE_TYPE_B && s->low_delay &&
2227         s->vol_control_parameters == 0 && !(s->flags & CODEC_FLAG_LOW_DELAY)) {
2228         av_log(s->avctx, AV_LOG_ERROR, "low_delay flag incorrectly, clearing it\n");
2229         s->low_delay = 0;
2230     }
2231
2232     s->partitioned_frame = s->data_partitioning && s->pict_type != AV_PICTURE_TYPE_B;
2233     if (s->partitioned_frame)
2234         s->decode_mb = mpeg4_decode_partitioned_mb;
2235     else
2236         s->decode_mb = mpeg4_decode_mb;
2237
2238     time_incr = 0;
2239     while (get_bits1(gb) != 0)
2240         time_incr++;
2241
2242     check_marker(gb, "before time_increment");
2243
2244     if (ctx->time_increment_bits == 0 ||
2245         !(show_bits(gb, ctx->time_increment_bits + 1) & 1)) {
2246         av_log(s->avctx, AV_LOG_ERROR,
2247                "hmm, seems the headers are not complete, trying to guess time_increment_bits\n");
2248
2249         for (ctx->time_increment_bits = 1;
2250              ctx->time_increment_bits < 16;
2251              ctx->time_increment_bits++) {
2252             if (s->pict_type == AV_PICTURE_TYPE_P ||
2253                 (s->pict_type == AV_PICTURE_TYPE_S &&
2254                  ctx->vol_sprite_usage == GMC_SPRITE)) {
2255                 if ((show_bits(gb, ctx->time_increment_bits + 6) & 0x37) == 0x30)
2256                     break;
2257             } else if ((show_bits(gb, ctx->time_increment_bits + 5) & 0x1F) == 0x18)
2258                 break;
2259         }
2260
2261         av_log(s->avctx, AV_LOG_ERROR,
2262                "my guess is %d bits ;)\n", ctx->time_increment_bits);
2263         if (s->avctx->time_base.den && 4*s->avctx->time_base.den < 1<<ctx->time_increment_bits) {
2264             s->avctx->time_base.den = 1<<ctx->time_increment_bits;
2265         }
2266     }
2267
2268     if (IS_3IV1)
2269         time_increment = get_bits1(gb);        // FIXME investigate further
2270     else
2271         time_increment = get_bits(gb, ctx->time_increment_bits);
2272
2273     if (s->pict_type != AV_PICTURE_TYPE_B) {
2274         s->last_time_base = s->time_base;
2275         s->time_base     += time_incr;
2276         s->time = s->time_base * s->avctx->time_base.den + time_increment;
2277         if (s->workaround_bugs & FF_BUG_UMP4) {
2278             if (s->time < s->last_non_b_time) {
2279                 /* header is not mpeg-4-compatible, broken encoder,
2280                  * trying to workaround */
2281                 s->time_base++;
2282                 s->time += s->avctx->time_base.den;
2283             }
2284         }
2285         s->pp_time         = s->time - s->last_non_b_time;
2286         s->last_non_b_time = s->time;
2287     } else {
2288         s->time    = (s->last_time_base + time_incr) * s->avctx->time_base.den + time_increment;
2289         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
2290         if (s->pp_time <= s->pb_time ||
2291             s->pp_time <= s->pp_time - s->pb_time ||
2292             s->pp_time <= 0) {
2293             /* messed up order, maybe after seeking? skipping current b-frame */
2294             return FRAME_SKIPPED;
2295         }
2296         ff_mpeg4_init_direct_mv(s);
2297
2298         if (ctx->t_frame == 0)
2299             ctx->t_frame = s->pb_time;
2300         if (ctx->t_frame == 0)
2301             ctx->t_frame = 1;  // 1/0 protection
2302         s->pp_field_time = (ROUNDED_DIV(s->last_non_b_time, ctx->t_frame) -
2303                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2304         s->pb_field_time = (ROUNDED_DIV(s->time, ctx->t_frame) -
2305                             ROUNDED_DIV(s->last_non_b_time - s->pp_time, ctx->t_frame)) * 2;
2306         if (s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1) {
2307             s->pb_field_time = 2;
2308             s->pp_field_time = 4;
2309             if (!s->progressive_sequence)
2310                 return FRAME_SKIPPED;
2311         }
2312     }
2313
2314     if (s->avctx->time_base.num)
2315         pts = ROUNDED_DIV(s->time, s->avctx->time_base.num);
2316     else
2317         pts = AV_NOPTS_VALUE;
2318     if (s->avctx->debug&FF_DEBUG_PTS)
2319         av_log(s->avctx, AV_LOG_DEBUG, "MPEG4 PTS: %"PRId64"\n",
2320                pts);
2321
2322     check_marker(gb, "before vop_coded");
2323
2324     /* vop coded */
2325     if (get_bits1(gb) != 1) {
2326         if (s->avctx->debug & FF_DEBUG_PICT_INFO)
2327             av_log(s->avctx, AV_LOG_ERROR, "vop not coded\n");
2328         return FRAME_SKIPPED;
2329     }
2330     if (ctx->new_pred)
2331         decode_new_pred(ctx, gb);
2332
2333     if (ctx->shape != BIN_ONLY_SHAPE &&
2334                     (s->pict_type == AV_PICTURE_TYPE_P ||
2335                      (s->pict_type == AV_PICTURE_TYPE_S &&
2336                       ctx->vol_sprite_usage == GMC_SPRITE))) {
2337         /* rounding type for motion estimation */
2338         s->no_rounding = get_bits1(gb);
2339     } else {
2340         s->no_rounding = 0;
2341     }
2342     // FIXME reduced res stuff
2343
2344     if (ctx->shape != RECT_SHAPE) {
2345         if (ctx->vol_sprite_usage != 1 || s->pict_type != AV_PICTURE_TYPE_I) {
2346             skip_bits(gb, 13);  /* width */
2347             skip_bits1(gb);     /* marker */
2348             skip_bits(gb, 13);  /* height */
2349             skip_bits1(gb);     /* marker */
2350             skip_bits(gb, 13);  /* hor_spat_ref */
2351             skip_bits1(gb);     /* marker */
2352             skip_bits(gb, 13);  /* ver_spat_ref */
2353         }
2354         skip_bits1(gb);         /* change_CR_disable */
2355
2356         if (get_bits1(gb) != 0)
2357             skip_bits(gb, 8);   /* constant_alpha_value */
2358     }
2359
2360     // FIXME complexity estimation stuff
2361
2362     if (ctx->shape != BIN_ONLY_SHAPE) {
2363         skip_bits_long(gb, ctx->cplx_estimation_trash_i);
2364         if (s->pict_type != AV_PICTURE_TYPE_I)
2365             skip_bits_long(gb, ctx->cplx_estimation_trash_p);
2366         if (s->pict_type == AV_PICTURE_TYPE_B)
2367             skip_bits_long(gb, ctx->cplx_estimation_trash_b);
2368
2369         if (get_bits_left(gb) < 3) {
2370             av_log(s->avctx, AV_LOG_ERROR, "Header truncated\n");
2371             return -1;
2372         }
2373         ctx->intra_dc_threshold = ff_mpeg4_dc_threshold[get_bits(gb, 3)];
2374         if (!s->progressive_sequence) {
2375             s->top_field_first = get_bits1(gb);
2376             s->alternate_scan  = get_bits1(gb);
2377         } else
2378             s->alternate_scan = 0;
2379     }
2380
2381     if (s->alternate_scan) {
2382         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable,   ff_alternate_vertical_scan);
2383         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable,   ff_alternate_vertical_scan);
2384         ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_vertical_scan);
2385         ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2386     } else {
2387         ff_init_scantable(s->dsp.idct_permutation, &s->inter_scantable,   ff_zigzag_direct);
2388         ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable,   ff_zigzag_direct);
2389         ff_init_scantable(s->dsp.idct_permutation, &s->intra_h_scantable, ff_alternate_horizontal_scan);
2390         ff_init_scantable(s->dsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
2391     }
2392
2393     if (s->pict_type == AV_PICTURE_TYPE_S &&
2394         (ctx->vol_sprite_usage == STATIC_SPRITE ||
2395          ctx->vol_sprite_usage == GMC_SPRITE)) {
2396         if (mpeg4_decode_sprite_trajectory(ctx, gb) < 0)
2397             return AVERROR_INVALIDDATA;
2398         if (ctx->sprite_brightness_change)
2399             av_log(s->avctx, AV_LOG_ERROR,
2400                    "sprite_brightness_change not supported\n");
2401         if (ctx->vol_sprite_usage == STATIC_SPRITE)
2402             av_log(s->avctx, AV_LOG_ERROR, "static sprite not supported\n");
2403     }
2404
2405     if (ctx->shape != BIN_ONLY_SHAPE) {
2406         s->chroma_qscale = s->qscale = get_bits(gb, s->quant_precision);
2407         if (s->qscale == 0) {
2408             av_log(s->avctx, AV_LOG_ERROR,
2409                    "Error, header damaged or not MPEG4 header (qscale=0)\n");
2410             return -1;  // makes no sense to continue, as there is nothing left from the image then
2411         }
2412
2413         if (s->pict_type != AV_PICTURE_TYPE_I) {
2414             s->f_code = get_bits(gb, 3);        /* fcode_for */
2415             if (s->f_code == 0) {
2416                 av_log(s->avctx, AV_LOG_ERROR,
2417                        "Error, header damaged or not MPEG4 header (f_code=0)\n");
2418                 s->f_code = 1;
2419                 return -1;  // makes no sense to continue, as there is nothing left from the image then
2420             }
2421         } else
2422             s->f_code = 1;
2423
2424         if (s->pict_type == AV_PICTURE_TYPE_B) {
2425             s->b_code = get_bits(gb, 3);
2426             if (s->b_code == 0) {
2427                 av_log(s->avctx, AV_LOG_ERROR,
2428                        "Error, header damaged or not MPEG4 header (b_code=0)\n");
2429                 s->b_code=1;
2430                 return -1; // makes no sense to continue, as the MV decoding will break very quickly
2431             }
2432         } else
2433             s->b_code = 1;
2434
2435         if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
2436             av_log(s->avctx, AV_LOG_DEBUG,
2437                    "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",
2438                    s->qscale, s->f_code, s->b_code,
2439                    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")),
2440                    gb->size_in_bits,s->progressive_sequence, s->alternate_scan,
2441                    s->top_field_first, s->quarter_sample ? "q" : "h",
2442                    s->data_partitioning, ctx->resync_marker,
2443                    ctx->num_sprite_warping_points, s->sprite_warping_accuracy,
2444                    1 - s->no_rounding, s->vo_type,
2445                    s->vol_control_parameters ? " VOLC" : " ", ctx->intra_dc_threshold,
2446                    ctx->cplx_estimation_trash_i, ctx->cplx_estimation_trash_p,
2447                    ctx->cplx_estimation_trash_b,
2448                    s->time,
2449                    time_increment
2450                   );
2451         }
2452
2453         if (!ctx->scalability) {
2454             if (ctx->shape != RECT_SHAPE && s->pict_type != AV_PICTURE_TYPE_I)
2455                 skip_bits1(gb);  // vop shape coding type
2456         } else {
2457             if (ctx->enhancement_type) {
2458                 int load_backward_shape = get_bits1(gb);
2459                 if (load_backward_shape)
2460                     av_log(s->avctx, AV_LOG_ERROR,
2461                            "load backward shape isn't supported\n");
2462             }
2463             skip_bits(gb, 2);  // ref_select_code
2464         }
2465     }
2466     /* detect buggy encoders which don't set the low_delay flag
2467      * (divx4/xvid/opendivx). Note we cannot detect divx5 without b-frames
2468      * easily (although it's buggy too) */
2469     if (s->vo_type == 0 && s->vol_control_parameters == 0 &&
2470         ctx->divx_version == -1 && s->picture_number == 0) {
2471         av_log(s->avctx, AV_LOG_WARNING,
2472                "looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag\n");
2473         s->low_delay = 1;
2474     }
2475
2476     s->picture_number++;  // better than pic number==0 always ;)
2477
2478     // FIXME add short header support
2479     s->y_dc_scale_table = ff_mpeg4_y_dc_scale_table;
2480     s->c_dc_scale_table = ff_mpeg4_c_dc_scale_table;
2481
2482     if (s->workaround_bugs & FF_BUG_EDGE) {
2483         s->h_edge_pos = s->width;
2484         s->v_edge_pos = s->height;
2485     }
2486     return 0;
2487 }
2488
2489 /**
2490  * Decode mpeg4 headers.
2491  * @return <0 if no VOP found (or a damaged one)
2492  *         FRAME_SKIPPED if a not coded VOP is found
2493  *         0 if a VOP is found
2494  */
2495 int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
2496 {
2497     MpegEncContext *s = &ctx->m;
2498     unsigned startcode, v;
2499
2500     /* search next start code */
2501     align_get_bits(gb);
2502
2503     if (s->codec_tag == AV_RL32("WV1F") && show_bits(gb, 24) == 0x575630) {
2504         skip_bits(gb, 24);
2505         if (get_bits(gb, 8) == 0xF0)
2506             goto end;
2507     }
2508
2509     startcode = 0xff;
2510     for (;;) {
2511         if (get_bits_count(gb) >= gb->size_in_bits) {
2512             if (gb->size_in_bits == 8 &&
2513                 (ctx->divx_version >= 0 || ctx->xvid_build >= 0) || s->codec_tag == AV_RL32("QMP4")) {
2514                 av_log(s->avctx, AV_LOG_VERBOSE, "frame skip %d\n", gb->size_in_bits);
2515                 return FRAME_SKIPPED;  // divx bug
2516             } else
2517                 return -1;  // end of stream
2518         }
2519
2520         /* use the bits after the test */
2521         v = get_bits(gb, 8);
2522         startcode = ((startcode << 8) | v) & 0xffffffff;
2523
2524         if ((startcode & 0xFFFFFF00) != 0x100)
2525             continue;  // no startcode
2526
2527         if (s->avctx->debug & FF_DEBUG_STARTCODE) {
2528             av_log(s->avctx, AV_LOG_DEBUG, "startcode: %3X ", startcode);
2529             if (startcode <= 0x11F)
2530                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Start");
2531             else if (startcode <= 0x12F)
2532                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Layer Start");
2533             else if (startcode <= 0x13F)
2534                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2535             else if (startcode <= 0x15F)
2536                 av_log(s->avctx, AV_LOG_DEBUG, "FGS bp start");
2537             else if (startcode <= 0x1AF)
2538                 av_log(s->avctx, AV_LOG_DEBUG, "Reserved");
2539             else if (startcode == 0x1B0)
2540                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq Start");
2541             else if (startcode == 0x1B1)
2542                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Seq End");
2543             else if (startcode == 0x1B2)
2544                 av_log(s->avctx, AV_LOG_DEBUG, "User Data");
2545             else if (startcode == 0x1B3)
2546                 av_log(s->avctx, AV_LOG_DEBUG, "Group of VOP start");
2547             else if (startcode == 0x1B4)
2548                 av_log(s->avctx, AV_LOG_DEBUG, "Video Session Error");
2549             else if (startcode == 0x1B5)
2550                 av_log(s->avctx, AV_LOG_DEBUG, "Visual Object Start");
2551             else if (startcode == 0x1B6)
2552                 av_log(s->avctx, AV_LOG_DEBUG, "Video Object Plane start");
2553             else if (startcode == 0x1B7)
2554                 av_log(s->avctx, AV_LOG_DEBUG, "slice start");
2555             else if (startcode == 0x1B8)
2556                 av_log(s->avctx, AV_LOG_DEBUG, "extension start");
2557             else if (startcode == 0x1B9)
2558                 av_log(s->avctx, AV_LOG_DEBUG, "fgs start");
2559             else if (startcode == 0x1BA)
2560                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object start");
2561             else if (startcode == 0x1BB)
2562                 av_log(s->avctx, AV_LOG_DEBUG, "FBA Object Plane start");
2563             else if (startcode == 0x1BC)
2564                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object start");
2565             else if (startcode == 0x1BD)
2566                 av_log(s->avctx, AV_LOG_DEBUG, "Mesh Object Plane start");
2567             else if (startcode == 0x1BE)
2568                 av_log(s->avctx, AV_LOG_DEBUG, "Still Texture Object start");
2569             else if (startcode == 0x1BF)
2570                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Spatial Layer start");
2571             else if (startcode == 0x1C0)
2572                 av_log(s->avctx, AV_LOG_DEBUG, "Texture SNR Layer start");
2573             else if (startcode == 0x1C1)
2574                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Tile start");
2575             else if (startcode == 0x1C2)
2576                 av_log(s->avctx, AV_LOG_DEBUG, "Texture Shape Layer start");
2577             else if (startcode == 0x1C3)
2578                 av_log(s->avctx, AV_LOG_DEBUG, "stuffing start");
2579             else if (startcode <= 0x1C5)
2580                 av_log(s->avctx, AV_LOG_DEBUG, "reserved");
2581             else if (startcode <= 0x1FF)
2582                 av_log(s->avctx, AV_LOG_DEBUG, "System start");
2583             av_log(s->avctx, AV_LOG_DEBUG, " at %d\n", get_bits_count(gb));
2584         }
2585
2586         if (startcode >= 0x120 && startcode <= 0x12F) {
2587             if (decode_vol_header(ctx, gb) < 0)
2588                 return -1;
2589         } else if (startcode == USER_DATA_STARTCODE) {
2590             decode_user_data(ctx, gb);
2591         } else if (startcode == GOP_STARTCODE) {
2592             mpeg4_decode_gop_header(s, gb);
2593         } else if (startcode == VOS_STARTCODE) {
2594             mpeg4_decode_profile_level(s, gb);
2595         } else if (startcode == VOP_STARTCODE) {
2596             break;
2597         }
2598
2599         align_get_bits(gb);
2600         startcode = 0xff;
2601     }
2602
2603 end:
2604     if (s->flags & CODEC_FLAG_LOW_DELAY)
2605         s->low_delay = 1;
2606     s->avctx->has_b_frames = !s->low_delay;
2607
2608     return decode_vop_header(ctx, gb);
2609 }
2610
2611 av_cold void ff_mpeg4videodec_static_init(void) {
2612     static int done = 0;
2613
2614     if (!done) {
2615         ff_init_rl(&ff_mpeg4_rl_intra, ff_mpeg4_static_rl_table_store[0]);
2616         ff_init_rl(&ff_rvlc_rl_inter, ff_mpeg4_static_rl_table_store[1]);
2617         ff_init_rl(&ff_rvlc_rl_intra, ff_mpeg4_static_rl_table_store[2]);
2618         INIT_VLC_RL(ff_mpeg4_rl_intra, 554);
2619         INIT_VLC_RL(ff_rvlc_rl_inter, 1072);
2620         INIT_VLC_RL(ff_rvlc_rl_intra, 1072);
2621         INIT_VLC_STATIC(&dc_lum, DC_VLC_BITS, 10 /* 13 */,
2622                         &ff_mpeg4_DCtab_lum[0][1], 2, 1,
2623                         &ff_mpeg4_DCtab_lum[0][0], 2, 1, 512);
2624         INIT_VLC_STATIC(&dc_chrom, DC_VLC_BITS, 10 /* 13 */,
2625                         &ff_mpeg4_DCtab_chrom[0][1], 2, 1,
2626                         &ff_mpeg4_DCtab_chrom[0][0], 2, 1, 512);
2627         INIT_VLC_STATIC(&sprite_trajectory, SPRITE_TRAJ_VLC_BITS, 15,
2628                         &ff_sprite_trajectory_tab[0][1], 4, 2,
2629                         &ff_sprite_trajectory_tab[0][0], 4, 2, 128);
2630         INIT_VLC_STATIC(&mb_type_b_vlc, MB_TYPE_B_VLC_BITS, 4,
2631                         &ff_mb_type_b_tab[0][1], 2, 1,
2632                         &ff_mb_type_b_tab[0][0], 2, 1, 16);
2633         done = 1;
2634     }
2635 }
2636
2637 int ff_mpeg4_frame_end(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
2638 {
2639     Mpeg4DecContext *ctx = avctx->priv_data;
2640     MpegEncContext    *s = &ctx->m;
2641
2642     /* divx 5.01+ bitstream reorder stuff */
2643     /* Since this clobbers the input buffer and hwaccel codecs still need the
2644      * data during hwaccel->end_frame we should not do this any earlier */
2645     if (s->divx_packed) {
2646         int current_pos     = s->gb.buffer == s->bitstream_buffer ? 0 : (get_bits_count(&s->gb) >> 3);
2647         int startcode_found = 0;
2648
2649         if (buf_size - current_pos > 7) {
2650
2651             int i;
2652             for (i = current_pos; i < buf_size - 4; i++)
2653
2654                 if (buf[i]     == 0 &&
2655                     buf[i + 1] == 0 &&
2656                     buf[i + 2] == 1 &&
2657                     buf[i + 3] == 0xB6) {
2658                     startcode_found = !(buf[i + 4] & 0x40);
2659                     break;
2660                 }
2661         }
2662
2663         if (startcode_found) {
2664             av_fast_padded_malloc(&s->bitstream_buffer,
2665                            &s->allocated_bitstream_buffer_size,
2666                            buf_size - current_pos);
2667             if (!s->bitstream_buffer)
2668                 return AVERROR(ENOMEM);
2669             memcpy(s->bitstream_buffer, buf + current_pos,
2670                    buf_size - current_pos);
2671             s->bitstream_buffer_size = buf_size - current_pos;
2672         }
2673     }
2674
2675     return 0;
2676 }
2677
2678 static int mpeg4_update_thread_context(AVCodecContext *dst,
2679                                        const AVCodecContext *src)
2680 {
2681     Mpeg4DecContext *s = dst->priv_data;
2682     const Mpeg4DecContext *s1 = src->priv_data;
2683
2684     int ret = ff_mpeg_update_thread_context(dst, src);
2685
2686     if (ret < 0)
2687         return ret;
2688
2689     memcpy(((uint8_t*)s) + sizeof(MpegEncContext), ((uint8_t*)s1) + sizeof(MpegEncContext), sizeof(Mpeg4DecContext) - sizeof(MpegEncContext));
2690
2691     return 0;
2692 }
2693
2694 static av_cold int decode_init(AVCodecContext *avctx)
2695 {
2696     Mpeg4DecContext *ctx = avctx->priv_data;
2697     MpegEncContext *s = &ctx->m;
2698     int ret;
2699
2700     ctx->divx_version =
2701     ctx->divx_build   =
2702     ctx->xvid_build   =
2703     ctx->lavc_build   = -1;
2704
2705     if ((ret = ff_h263_decode_init(avctx)) < 0)
2706         return ret;
2707
2708     ff_mpeg4videodec_static_init();
2709
2710     s->h263_pred = 1;
2711     s->low_delay = 0; /* default, might be overridden in the vol header during header parsing */
2712     s->decode_mb = mpeg4_decode_mb;
2713     ctx->time_increment_bits = 4; /* default value for broken headers */
2714
2715     avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
2716     avctx->internal->allocate_progress = 1;
2717
2718     return 0;
2719 }
2720
2721 static const AVProfile mpeg4_video_profiles[] = {
2722     { FF_PROFILE_MPEG4_SIMPLE,                    "Simple Profile" },
2723     { FF_PROFILE_MPEG4_SIMPLE_SCALABLE,           "Simple Scalable Profile" },
2724     { FF_PROFILE_MPEG4_CORE,                      "Core Profile" },
2725     { FF_PROFILE_MPEG4_MAIN,                      "Main Profile" },
2726     { FF_PROFILE_MPEG4_N_BIT,                     "N-bit Profile" },
2727     { FF_PROFILE_MPEG4_SCALABLE_TEXTURE,          "Scalable Texture Profile" },
2728     { FF_PROFILE_MPEG4_SIMPLE_FACE_ANIMATION,     "Simple Face Animation Profile" },
2729     { FF_PROFILE_MPEG4_BASIC_ANIMATED_TEXTURE,    "Basic Animated Texture Profile" },
2730     { FF_PROFILE_MPEG4_HYBRID,                    "Hybrid Profile" },
2731     { FF_PROFILE_MPEG4_ADVANCED_REAL_TIME,        "Advanced Real Time Simple Profile" },
2732     { FF_PROFILE_MPEG4_CORE_SCALABLE,             "Code Scalable Profile" },
2733     { FF_PROFILE_MPEG4_ADVANCED_CODING,           "Advanced Coding Profile" },
2734     { FF_PROFILE_MPEG4_ADVANCED_CORE,             "Advanced Core Profile" },
2735     { FF_PROFILE_MPEG4_ADVANCED_SCALABLE_TEXTURE, "Advanced Scalable Texture Profile" },
2736     { FF_PROFILE_MPEG4_SIMPLE_STUDIO,             "Simple Studio Profile" },
2737     { FF_PROFILE_MPEG4_ADVANCED_SIMPLE,           "Advanced Simple Profile" },
2738     { FF_PROFILE_UNKNOWN },
2739 };
2740
2741 static const AVOption mpeg4_options[] = {
2742     {"quarter_sample", "1/4 subpel MC", offsetof(MpegEncContext, quarter_sample), FF_OPT_TYPE_INT, {.i64 = 0}, 0, 1, 0},
2743     {"divx_packed", "divx style packed b frames", offsetof(MpegEncContext, divx_packed), FF_OPT_TYPE_INT, {.i64 = 0}, 0, 1, 0},
2744     {NULL}
2745 };
2746
2747 static const AVClass mpeg4_class = {
2748     "MPEG4 Video Decoder",
2749     av_default_item_name,
2750     mpeg4_options,
2751     LIBAVUTIL_VERSION_INT,
2752 };
2753
2754 static const AVClass mpeg4_vdpau_class = {
2755     "MPEG4 Video VDPAU Decoder",
2756     av_default_item_name,
2757     mpeg4_options,
2758     LIBAVUTIL_VERSION_INT,
2759 };
2760
2761 AVCodec ff_mpeg4_decoder = {
2762     .name                  = "mpeg4",
2763     .long_name             = NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
2764     .type                  = AVMEDIA_TYPE_VIDEO,
2765     .id                    = AV_CODEC_ID_MPEG4,
2766     .priv_data_size        = sizeof(Mpeg4DecContext),
2767     .init                  = decode_init,
2768     .close                 = ff_h263_decode_end,
2769     .decode                = ff_h263_decode_frame,
2770     .capabilities          = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
2771                              CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
2772                              CODEC_CAP_FRAME_THREADS,
2773     .flush                 = ff_mpeg_flush,
2774     .max_lowres            = 3,
2775     .pix_fmts              = ff_h263_hwaccel_pixfmt_list_420,
2776     .profiles              = NULL_IF_CONFIG_SMALL(mpeg4_video_profiles),
2777     .update_thread_context = ONLY_IF_THREADS_ENABLED(mpeg4_update_thread_context),
2778     .priv_class = &mpeg4_class,
2779 };
2780
2781
2782 #if CONFIG_MPEG4_VDPAU_DECODER
2783 AVCodec ff_mpeg4_vdpau_decoder = {
2784     .name           = "mpeg4_vdpau",
2785     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 part 2 (VDPAU)"),
2786     .type           = AVMEDIA_TYPE_VIDEO,
2787     .id             = AV_CODEC_ID_MPEG4,
2788     .priv_data_size = sizeof(MpegEncContext),
2789     .init           = decode_init,
2790     .close          = ff_h263_decode_end,
2791     .decode         = ff_h263_decode_frame,
2792     .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY |
2793                       CODEC_CAP_HWACCEL_VDPAU,
2794     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_VDPAU_MPEG4,
2795                                                   AV_PIX_FMT_NONE },
2796     .priv_class     = &mpeg4_vdpau_class,
2797 };
2798 #endif