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1 /*
2  * H.263 decoder
3  * Copyright (c) 2001 Fabrice Bellard
4  * Copyright (c) 2002-2004 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 /**
24  * @file
25  * H.263 decoder.
26  */
27 
28 #define UNCHECKED_BITSTREAM_READER 1
29 
30 #include "libavutil/cpu.h"
31 #include "libavutil/video_enc_params.h"
32 
33 #include "avcodec.h"
34 #include "error_resilience.h"
35 #include "flv.h"
36 #include "h263.h"
37 #include "h263_parser.h"
38 #include "hwconfig.h"
39 #include "internal.h"
40 #include "mpeg_er.h"
41 #include "mpeg4video.h"
42 #include "mpeg4video_parser.h"
43 #include "mpegutils.h"
44 #include "mpegvideo.h"
45 #include "msmpeg4.h"
46 #include "qpeldsp.h"
47 #include "thread.h"
48 #include "wmv2.h"
49 
h263_get_format(AVCodecContext * avctx)50 static enum AVPixelFormat h263_get_format(AVCodecContext *avctx)
51 {
52     /* MPEG-4 Studio Profile only, not supported by hardware */
53     if (avctx->bits_per_raw_sample > 8) {
54         av_assert1(((MpegEncContext *)avctx->priv_data)->studio_profile);
55         return avctx->pix_fmt;
56     }
57 
58     if (avctx->codec->id == AV_CODEC_ID_MSS2)
59         return AV_PIX_FMT_YUV420P;
60 
61     if (CONFIG_GRAY && (avctx->flags & AV_CODEC_FLAG_GRAY)) {
62         if (avctx->color_range == AVCOL_RANGE_UNSPECIFIED)
63             avctx->color_range = AVCOL_RANGE_MPEG;
64         return AV_PIX_FMT_GRAY8;
65     }
66 
67     return avctx->pix_fmt = ff_get_format(avctx, avctx->codec->pix_fmts);
68 }
69 
ff_h263_decode_init(AVCodecContext * avctx)70 av_cold int ff_h263_decode_init(AVCodecContext *avctx)
71 {
72     MpegEncContext *s = avctx->priv_data;
73     int ret;
74 
75     s->out_format      = FMT_H263;
76 
77     // set defaults
78     ff_mpv_decode_init(s, avctx);
79 
80     s->quant_precision = 5;
81     s->decode_mb       = ff_h263_decode_mb;
82     s->low_delay       = 1;
83     s->unrestricted_mv = 1;
84 
85     /* select sub codec */
86     switch (avctx->codec->id) {
87     case AV_CODEC_ID_H263:
88     case AV_CODEC_ID_H263P:
89         s->unrestricted_mv = 0;
90         avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
91         break;
92     case AV_CODEC_ID_MPEG4:
93         break;
94     case AV_CODEC_ID_MSMPEG4V1:
95         s->h263_pred       = 1;
96         s->msmpeg4_version = 1;
97         break;
98     case AV_CODEC_ID_MSMPEG4V2:
99         s->h263_pred       = 1;
100         s->msmpeg4_version = 2;
101         break;
102     case AV_CODEC_ID_MSMPEG4V3:
103         s->h263_pred       = 1;
104         s->msmpeg4_version = 3;
105         break;
106     case AV_CODEC_ID_WMV1:
107         s->h263_pred       = 1;
108         s->msmpeg4_version = 4;
109         break;
110     case AV_CODEC_ID_WMV2:
111         s->h263_pred       = 1;
112         s->msmpeg4_version = 5;
113         break;
114     case AV_CODEC_ID_VC1:
115     case AV_CODEC_ID_WMV3:
116     case AV_CODEC_ID_VC1IMAGE:
117     case AV_CODEC_ID_WMV3IMAGE:
118     case AV_CODEC_ID_MSS2:
119         s->h263_pred       = 1;
120         s->msmpeg4_version = 6;
121         avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
122         break;
123     case AV_CODEC_ID_H263I:
124         break;
125     case AV_CODEC_ID_FLV1:
126         s->h263_flv = 1;
127         break;
128     default:
129         av_log(avctx, AV_LOG_ERROR, "Unsupported codec %d\n",
130                avctx->codec->id);
131         return AVERROR(ENOSYS);
132     }
133     s->codec_id    = avctx->codec->id;
134 
135     if (avctx->codec_tag == AV_RL32("L263") || avctx->codec_tag == AV_RL32("S263"))
136         if (avctx->extradata_size == 56 && avctx->extradata[0] == 1)
137             s->ehc_mode = 1;
138 
139     /* for H.263, we allocate the images after having read the header */
140     if (avctx->codec->id != AV_CODEC_ID_H263 &&
141         avctx->codec->id != AV_CODEC_ID_H263P &&
142         avctx->codec->id != AV_CODEC_ID_MPEG4) {
143         avctx->pix_fmt = h263_get_format(avctx);
144         ff_mpv_idct_init(s);
145         if ((ret = ff_mpv_common_init(s)) < 0)
146             return ret;
147     }
148 
149     ff_h263dsp_init(&s->h263dsp);
150     ff_qpeldsp_init(&s->qdsp);
151     ff_h263_decode_init_vlc();
152 
153     return 0;
154 }
155 
ff_h263_decode_end(AVCodecContext * avctx)156 av_cold int ff_h263_decode_end(AVCodecContext *avctx)
157 {
158     MpegEncContext *s = avctx->priv_data;
159 
160     ff_mpv_common_end(s);
161     return 0;
162 }
163 
164 /**
165  * Return the number of bytes consumed for building the current frame.
166  */
get_consumed_bytes(MpegEncContext * s,int buf_size)167 static int get_consumed_bytes(MpegEncContext *s, int buf_size)
168 {
169     int pos = (get_bits_count(&s->gb) + 7) >> 3;
170 
171     if (s->divx_packed || s->avctx->hwaccel) {
172         /* We would have to scan through the whole buf to handle the weird
173          * reordering ... */
174         return buf_size;
175     } else if (s->avctx->flags & AV_CODEC_FLAG_TRUNCATED) {
176         pos -= s->parse_context.last_index;
177         // padding is not really read so this might be -1
178         if (pos < 0)
179             pos = 0;
180         return pos;
181     } else {
182         // avoid infinite loops (maybe not needed...)
183         if (pos == 0)
184             pos = 1;
185         // oops ;)
186         if (pos + 10 > buf_size)
187             pos = buf_size;
188 
189         return pos;
190     }
191 }
192 
decode_slice(MpegEncContext * s)193 static int decode_slice(MpegEncContext *s)
194 {
195     const int part_mask = s->partitioned_frame
196                           ? (ER_AC_END | ER_AC_ERROR) : 0x7F;
197     const int mb_size   = 16 >> s->avctx->lowres;
198     int ret;
199 
200     s->last_resync_gb   = s->gb;
201     s->first_slice_line = 1;
202     s->resync_mb_x      = s->mb_x;
203     s->resync_mb_y      = s->mb_y;
204 
205     ff_set_qscale(s, s->qscale);
206 
207     if (s->studio_profile) {
208         if ((ret = ff_mpeg4_decode_studio_slice_header(s->avctx->priv_data)) < 0)
209             return ret;
210     }
211 
212     if (s->avctx->hwaccel) {
213         const uint8_t *start = s->gb.buffer + get_bits_count(&s->gb) / 8;
214         ret = s->avctx->hwaccel->decode_slice(s->avctx, start, s->gb.buffer_end - start);
215         // ensure we exit decode loop
216         s->mb_y = s->mb_height;
217         return ret;
218     }
219 
220     if (s->partitioned_frame) {
221         const int qscale = s->qscale;
222 
223         if (CONFIG_MPEG4_DECODER && s->codec_id == AV_CODEC_ID_MPEG4)
224             if ((ret = ff_mpeg4_decode_partitions(s->avctx->priv_data)) < 0)
225                 return ret;
226 
227         /* restore variables which were modified */
228         s->first_slice_line = 1;
229         s->mb_x             = s->resync_mb_x;
230         s->mb_y             = s->resync_mb_y;
231         ff_set_qscale(s, qscale);
232     }
233 
234     for (; s->mb_y < s->mb_height; s->mb_y++) {
235         /* per-row end of slice checks */
236         if (s->msmpeg4_version) {
237             if (s->resync_mb_y + s->slice_height == s->mb_y) {
238                 ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
239                                 s->mb_x - 1, s->mb_y, ER_MB_END);
240 
241                 return 0;
242             }
243         }
244 
245         if (s->msmpeg4_version == 1) {
246             s->last_dc[0] =
247             s->last_dc[1] =
248             s->last_dc[2] = 128;
249         }
250 
251         ff_init_block_index(s);
252         for (; s->mb_x < s->mb_width; s->mb_x++) {
253             int ret;
254 
255             ff_update_block_index(s);
256 
257             if (s->resync_mb_x == s->mb_x && s->resync_mb_y + 1 == s->mb_y)
258                 s->first_slice_line = 0;
259 
260             /* DCT & quantize */
261 
262             s->mv_dir  = MV_DIR_FORWARD;
263             s->mv_type = MV_TYPE_16X16;
264             ff_dlog(s, "%d %06X\n",
265                     get_bits_count(&s->gb), show_bits(&s->gb, 24));
266 
267             ff_tlog(NULL, "Decoding MB at %dx%d\n", s->mb_x, s->mb_y);
268             ret = s->decode_mb(s, s->block);
269 
270             if (s->pict_type != AV_PICTURE_TYPE_B)
271                 ff_h263_update_motion_val(s);
272 
273             if (ret < 0) {
274                 const int xy = s->mb_x + s->mb_y * s->mb_stride;
275                 if (ret == SLICE_END) {
276                     ff_mpv_reconstruct_mb(s, s->block);
277                     if (s->loop_filter)
278                         ff_h263_loop_filter(s);
279 
280                     ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
281                                     s->mb_x, s->mb_y, ER_MB_END & part_mask);
282 
283                     s->padding_bug_score--;
284 
285                     if (++s->mb_x >= s->mb_width) {
286                         s->mb_x = 0;
287                         ff_mpeg_draw_horiz_band(s, s->mb_y * mb_size, mb_size);
288                         ff_mpv_report_decode_progress(s);
289                         s->mb_y++;
290                     }
291                     return 0;
292                 } else if (ret == SLICE_NOEND) {
293                     av_log(s->avctx, AV_LOG_ERROR,
294                            "Slice mismatch at MB: %d\n", xy);
295                     ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
296                                     s->mb_x + 1, s->mb_y,
297                                     ER_MB_END & part_mask);
298                     return AVERROR_INVALIDDATA;
299                 }
300                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
301                 ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
302                                 s->mb_x, s->mb_y, ER_MB_ERROR & part_mask);
303 
304                 if (s->avctx->err_recognition & AV_EF_IGNORE_ERR)
305                     continue;
306                 return AVERROR_INVALIDDATA;
307             }
308 
309             ff_mpv_reconstruct_mb(s, s->block);
310             if (s->loop_filter)
311                 ff_h263_loop_filter(s);
312         }
313 
314         ff_mpeg_draw_horiz_band(s, s->mb_y * mb_size, mb_size);
315         ff_mpv_report_decode_progress(s);
316 
317         s->mb_x = 0;
318     }
319 
320     av_assert1(s->mb_x == 0 && s->mb_y == s->mb_height);
321 
322     // Detect incorrect padding with wrong stuffing codes used by NEC N-02B
323     if (s->codec_id == AV_CODEC_ID_MPEG4         &&
324         (s->workaround_bugs & FF_BUG_AUTODETECT) &&
325         get_bits_left(&s->gb) >= 48              &&
326         show_bits(&s->gb, 24) == 0x4010          &&
327         !s->data_partitioning)
328         s->padding_bug_score += 32;
329 
330     /* try to detect the padding bug */
331     if (s->codec_id == AV_CODEC_ID_MPEG4         &&
332         (s->workaround_bugs & FF_BUG_AUTODETECT) &&
333         get_bits_left(&s->gb) >= 0               &&
334         get_bits_left(&s->gb) < 137              &&
335         !s->data_partitioning) {
336         const int bits_count = get_bits_count(&s->gb);
337         const int bits_left  = s->gb.size_in_bits - bits_count;
338 
339         if (bits_left == 0) {
340             s->padding_bug_score += 16;
341         } else if (bits_left != 1) {
342             int v = show_bits(&s->gb, 8);
343             v |= 0x7F >> (7 - (bits_count & 7));
344 
345             if (v == 0x7F && bits_left <= 8)
346                 s->padding_bug_score--;
347             else if (v == 0x7F && ((get_bits_count(&s->gb) + 8) & 8) &&
348                      bits_left <= 16)
349                 s->padding_bug_score += 4;
350             else
351                 s->padding_bug_score++;
352         }
353     }
354 
355     if (s->codec_id == AV_CODEC_ID_H263          &&
356         (s->workaround_bugs & FF_BUG_AUTODETECT) &&
357         get_bits_left(&s->gb) >= 8               &&
358         get_bits_left(&s->gb) < 300              &&
359         s->pict_type == AV_PICTURE_TYPE_I        &&
360         show_bits(&s->gb, 8) == 0                &&
361         !s->data_partitioning) {
362 
363         s->padding_bug_score += 32;
364     }
365 
366     if (s->codec_id == AV_CODEC_ID_H263          &&
367         (s->workaround_bugs & FF_BUG_AUTODETECT) &&
368         get_bits_left(&s->gb) >= 64              &&
369         AV_RB64(s->gb.buffer_end - 8) == 0xCDCDCDCDFC7F0000) {
370 
371         s->padding_bug_score += 32;
372     }
373 
374     if (s->workaround_bugs & FF_BUG_AUTODETECT) {
375         if (
376             (s->padding_bug_score > -2 && !s->data_partitioning))
377             s->workaround_bugs |= FF_BUG_NO_PADDING;
378         else
379             s->workaround_bugs &= ~FF_BUG_NO_PADDING;
380     }
381 
382     // handle formats which don't have unique end markers
383     if (s->msmpeg4_version || (s->workaround_bugs & FF_BUG_NO_PADDING)) { // FIXME perhaps solve this more cleanly
384         int left      = get_bits_left(&s->gb);
385         int max_extra = 7;
386 
387         /* no markers in M$ crap */
388         if (s->msmpeg4_version && s->pict_type == AV_PICTURE_TYPE_I)
389             max_extra += 17;
390 
391         /* buggy padding but the frame should still end approximately at
392          * the bitstream end */
393         if ((s->workaround_bugs & FF_BUG_NO_PADDING) &&
394             (s->avctx->err_recognition & (AV_EF_BUFFER|AV_EF_AGGRESSIVE)))
395             max_extra += 48;
396         else if ((s->workaround_bugs & FF_BUG_NO_PADDING))
397             max_extra += 256 * 256 * 256 * 64;
398 
399         if (left > max_extra)
400             av_log(s->avctx, AV_LOG_ERROR,
401                    "discarding %d junk bits at end, next would be %X\n",
402                    left, show_bits(&s->gb, 24));
403         else if (left < 0)
404             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
405         else
406             ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y,
407                             s->mb_x - 1, s->mb_y, ER_MB_END);
408 
409         return 0;
410     }
411 
412     av_log(s->avctx, AV_LOG_ERROR,
413            "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
414            get_bits_left(&s->gb), show_bits(&s->gb, 24), s->padding_bug_score);
415 
416     ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y,
417                     ER_MB_END & part_mask);
418 
419     return AVERROR_INVALIDDATA;
420 }
421 
ff_h263_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)422 int ff_h263_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
423                          AVPacket *avpkt)
424 {
425     const uint8_t *buf = avpkt->data;
426     int buf_size       = avpkt->size;
427     MpegEncContext *s  = avctx->priv_data;
428     int ret;
429     int slice_ret = 0;
430     AVFrame *pict = data;
431 
432     /* no supplementary picture */
433     if (buf_size == 0) {
434         /* special case for last picture */
435         if (s->low_delay == 0 && s->next_picture_ptr) {
436             if ((ret = av_frame_ref(pict, s->next_picture_ptr->f)) < 0)
437                 return ret;
438             s->next_picture_ptr = NULL;
439 
440             *got_frame = 1;
441         }
442 
443         return 0;
444     }
445 
446     if (s->avctx->flags & AV_CODEC_FLAG_TRUNCATED) {
447         int next;
448 
449         if (CONFIG_MPEG4_DECODER && s->codec_id == AV_CODEC_ID_MPEG4) {
450             next = ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
451         } else if (CONFIG_H263_DECODER && s->codec_id == AV_CODEC_ID_H263) {
452             next = ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
453         } else if (CONFIG_H263P_DECODER && s->codec_id == AV_CODEC_ID_H263P) {
454             next = ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
455         } else {
456             av_log(s->avctx, AV_LOG_ERROR,
457                    "this codec does not support truncated bitstreams\n");
458             return AVERROR(ENOSYS);
459         }
460 
461         if (ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf,
462                              &buf_size) < 0)
463             return buf_size;
464     }
465 
466 retry:
467     if (s->divx_packed && s->bitstream_buffer_size) {
468         int i;
469         for(i=0; i < buf_size-3; i++) {
470             if (buf[i]==0 && buf[i+1]==0 && buf[i+2]==1) {
471                 if (buf[i+3]==0xB0) {
472                     av_log(s->avctx, AV_LOG_WARNING, "Discarding excessive bitstream in packed xvid\n");
473                     s->bitstream_buffer_size = 0;
474                 }
475                 break;
476             }
477         }
478     }
479 
480     if (s->bitstream_buffer_size && (s->divx_packed || buf_size <= MAX_NVOP_SIZE)) // divx 5.01+/xvid frame reorder
481         ret = init_get_bits8(&s->gb, s->bitstream_buffer,
482                              s->bitstream_buffer_size);
483     else
484         ret = init_get_bits8(&s->gb, buf, buf_size);
485 
486     s->bitstream_buffer_size = 0;
487     if (ret < 0)
488         return ret;
489 
490     if (!s->context_initialized)
491         // we need the idct permutation for reading a custom matrix
492         ff_mpv_idct_init(s);
493 
494     /* let's go :-) */
495     if (CONFIG_WMV2_DECODER && s->msmpeg4_version == 5) {
496         ret = ff_wmv2_decode_picture_header(s);
497     } else if (CONFIG_MSMPEG4_DECODER && s->msmpeg4_version) {
498         ret = ff_msmpeg4_decode_picture_header(s);
499     } else if (CONFIG_MPEG4_DECODER && avctx->codec_id == AV_CODEC_ID_MPEG4) {
500         if (s->avctx->extradata_size && s->picture_number == 0) {
501             GetBitContext gb;
502 
503             if (init_get_bits8(&gb, s->avctx->extradata, s->avctx->extradata_size) >= 0 )
504                 ff_mpeg4_decode_picture_header(avctx->priv_data, &gb, 1);
505         }
506         ret = ff_mpeg4_decode_picture_header(avctx->priv_data, &s->gb, 0);
507     } else if (CONFIG_H263I_DECODER && s->codec_id == AV_CODEC_ID_H263I) {
508         ret = ff_intel_h263_decode_picture_header(s);
509     } else if (CONFIG_FLV_DECODER && s->h263_flv) {
510         ret = ff_flv_decode_picture_header(s);
511     } else {
512         ret = ff_h263_decode_picture_header(s);
513     }
514 
515     if (ret < 0 || ret == FRAME_SKIPPED) {
516         if (   s->width  != avctx->coded_width
517             || s->height != avctx->coded_height) {
518                 av_log(s->avctx, AV_LOG_WARNING, "Reverting picture dimensions change due to header decoding failure\n");
519                 s->width = avctx->coded_width;
520                 s->height= avctx->coded_height;
521         }
522     }
523     if (ret == FRAME_SKIPPED)
524         return get_consumed_bytes(s, buf_size);
525 
526     /* skip if the header was thrashed */
527     if (ret < 0) {
528         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
529         return ret;
530     }
531 
532     if (!s->context_initialized) {
533         avctx->pix_fmt = h263_get_format(avctx);
534         if ((ret = ff_mpv_common_init(s)) < 0)
535             return ret;
536     }
537 
538     if (!s->current_picture_ptr || s->current_picture_ptr->f->data[0]) {
539         int i = ff_find_unused_picture(s->avctx, s->picture, 0);
540         if (i < 0)
541             return i;
542         s->current_picture_ptr = &s->picture[i];
543     }
544 
545     avctx->has_b_frames = !s->low_delay;
546 
547     if (CONFIG_MPEG4_DECODER && avctx->codec_id == AV_CODEC_ID_MPEG4) {
548         if (ff_mpeg4_workaround_bugs(avctx) == 1)
549             goto retry;
550         if (s->studio_profile != (s->idsp.idct == NULL))
551             ff_mpv_idct_init(s);
552     }
553 
554     /* After H.263 & MPEG-4 header decode we have the height, width,
555      * and other parameters. So then we could init the picture.
556      * FIXME: By the way H.263 decoder is evolving it should have
557      * an H263EncContext */
558     if (s->width  != avctx->coded_width  ||
559         s->height != avctx->coded_height ||
560         s->context_reinit) {
561         /* H.263 could change picture size any time */
562         s->context_reinit = 0;
563 
564         ret = ff_set_dimensions(avctx, s->width, s->height);
565         if (ret < 0)
566             return ret;
567 
568         ff_set_sar(avctx, avctx->sample_aspect_ratio);
569 
570         if ((ret = ff_mpv_common_frame_size_change(s)))
571             return ret;
572 
573         if (avctx->pix_fmt != h263_get_format(avctx)) {
574             av_log(avctx, AV_LOG_ERROR, "format change not supported\n");
575             avctx->pix_fmt = AV_PIX_FMT_NONE;
576             return AVERROR_UNKNOWN;
577         }
578     }
579 
580     if (s->codec_id == AV_CODEC_ID_H263  ||
581         s->codec_id == AV_CODEC_ID_H263P ||
582         s->codec_id == AV_CODEC_ID_H263I)
583         s->gob_index = H263_GOB_HEIGHT(s->height);
584 
585     // for skipping the frame
586     s->current_picture.f->pict_type = s->pict_type;
587     s->current_picture.f->key_frame = s->pict_type == AV_PICTURE_TYPE_I;
588 
589     /* skip B-frames if we don't have reference frames */
590     if (!s->last_picture_ptr &&
591         (s->pict_type == AV_PICTURE_TYPE_B || s->droppable))
592         return get_consumed_bytes(s, buf_size);
593     if ((avctx->skip_frame >= AVDISCARD_NONREF &&
594          s->pict_type == AV_PICTURE_TYPE_B)    ||
595         (avctx->skip_frame >= AVDISCARD_NONKEY &&
596          s->pict_type != AV_PICTURE_TYPE_I)    ||
597         avctx->skip_frame >= AVDISCARD_ALL)
598         return get_consumed_bytes(s, buf_size);
599 
600     if (s->next_p_frame_damaged) {
601         if (s->pict_type == AV_PICTURE_TYPE_B)
602             return get_consumed_bytes(s, buf_size);
603         else
604             s->next_p_frame_damaged = 0;
605     }
606 
607     if ((!s->no_rounding) || s->pict_type == AV_PICTURE_TYPE_B) {
608         s->me.qpel_put = s->qdsp.put_qpel_pixels_tab;
609         s->me.qpel_avg = s->qdsp.avg_qpel_pixels_tab;
610     } else {
611         s->me.qpel_put = s->qdsp.put_no_rnd_qpel_pixels_tab;
612         s->me.qpel_avg = s->qdsp.avg_qpel_pixels_tab;
613     }
614 
615     if ((ret = ff_mpv_frame_start(s, avctx)) < 0)
616         return ret;
617 
618     if (!s->divx_packed && !avctx->hwaccel)
619         ff_thread_finish_setup(avctx);
620 
621     if (avctx->hwaccel) {
622         ret = avctx->hwaccel->start_frame(avctx, s->gb.buffer,
623                                           s->gb.buffer_end - s->gb.buffer);
624         if (ret < 0 )
625             return ret;
626     }
627 
628     ff_mpeg_er_frame_start(s);
629 
630     /* the second part of the wmv2 header contains the MB skip bits which
631      * are stored in current_picture->mb_type which is not available before
632      * ff_mpv_frame_start() */
633     if (CONFIG_WMV2_DECODER && s->msmpeg4_version == 5) {
634         ret = ff_wmv2_decode_secondary_picture_header(s);
635         if (ret < 0)
636             return ret;
637         if (ret == 1)
638             goto frame_end;
639     }
640 
641     /* decode each macroblock */
642     s->mb_x = 0;
643     s->mb_y = 0;
644 
645     slice_ret = decode_slice(s);
646     while (s->mb_y < s->mb_height) {
647         if (s->msmpeg4_version) {
648             if (s->slice_height == 0 || s->mb_x != 0 || slice_ret < 0 ||
649                 (s->mb_y % s->slice_height) != 0 || get_bits_left(&s->gb) < 0)
650                 break;
651         } else {
652             int prev_x = s->mb_x, prev_y = s->mb_y;
653             if (ff_h263_resync(s) < 0)
654                 break;
655             if (prev_y * s->mb_width + prev_x < s->mb_y * s->mb_width + s->mb_x)
656                 s->er.error_occurred = 1;
657         }
658 
659         if (s->msmpeg4_version < 4 && s->h263_pred)
660             ff_mpeg4_clean_buffers(s);
661 
662         if (decode_slice(s) < 0)
663             slice_ret = AVERROR_INVALIDDATA;
664     }
665 
666     if (s->msmpeg4_version && s->msmpeg4_version < 4 &&
667         s->pict_type == AV_PICTURE_TYPE_I)
668         if (!CONFIG_MSMPEG4_DECODER ||
669             ff_msmpeg4_decode_ext_header(s, buf_size) < 0)
670             s->er.error_status_table[s->mb_num - 1] = ER_MB_ERROR;
671 
672     av_assert1(s->bitstream_buffer_size == 0);
673 frame_end:
674     if (!s->studio_profile)
675         ff_er_frame_end(&s->er);
676 
677     if (avctx->hwaccel) {
678         ret = avctx->hwaccel->end_frame(avctx);
679         if (ret < 0)
680             return ret;
681     }
682 
683     ff_mpv_frame_end(s);
684 
685     if (CONFIG_MPEG4_DECODER && avctx->codec_id == AV_CODEC_ID_MPEG4)
686         ff_mpeg4_frame_end(avctx, buf, buf_size);
687 
688     if (!s->divx_packed && avctx->hwaccel)
689         ff_thread_finish_setup(avctx);
690 
691     av_assert1(s->current_picture.f->pict_type == s->current_picture_ptr->f->pict_type);
692     av_assert1(s->current_picture.f->pict_type == s->pict_type);
693     if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {
694         if ((ret = av_frame_ref(pict, s->current_picture_ptr->f)) < 0)
695             return ret;
696         ff_print_debug_info(s, s->current_picture_ptr, pict);
697         ff_mpv_export_qp_table(s, pict, s->current_picture_ptr, FF_QSCALE_TYPE_MPEG1);
698     } else if (s->last_picture_ptr) {
699         if ((ret = av_frame_ref(pict, s->last_picture_ptr->f)) < 0)
700             return ret;
701         ff_print_debug_info(s, s->last_picture_ptr, pict);
702         ff_mpv_export_qp_table(s, pict, s->last_picture_ptr, FF_QSCALE_TYPE_MPEG1);
703     }
704 
705     if (s->last_picture_ptr || s->low_delay) {
706         if (   pict->format == AV_PIX_FMT_YUV420P
707             && (s->codec_tag == AV_RL32("GEOV") || s->codec_tag == AV_RL32("GEOX"))) {
708             int x, y, p;
709             av_frame_make_writable(pict);
710             for (p=0; p<3; p++) {
711                 int w = AV_CEIL_RSHIFT(pict-> width, !!p);
712                 int h = AV_CEIL_RSHIFT(pict->height, !!p);
713                 int linesize = pict->linesize[p];
714                 for (y=0; y<(h>>1); y++)
715                     for (x=0; x<w; x++)
716                         FFSWAP(int,
717                                pict->data[p][x + y*linesize],
718                                pict->data[p][x + (h-1-y)*linesize]);
719             }
720         }
721         *got_frame = 1;
722     }
723 
724     if (slice_ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
725         return slice_ret;
726     else
727         return get_consumed_bytes(s, buf_size);
728 }
729 
730 const enum AVPixelFormat ff_h263_hwaccel_pixfmt_list_420[] = {
731 #if CONFIG_H263_VAAPI_HWACCEL || CONFIG_MPEG4_VAAPI_HWACCEL
732     AV_PIX_FMT_VAAPI,
733 #endif
734 #if CONFIG_MPEG4_NVDEC_HWACCEL
735     AV_PIX_FMT_CUDA,
736 #endif
737 #if CONFIG_MPEG4_VDPAU_HWACCEL
738     AV_PIX_FMT_VDPAU,
739 #endif
740 #if CONFIG_H263_VIDEOTOOLBOX_HWACCEL || CONFIG_MPEG4_VIDEOTOOLBOX_HWACCEL
741     AV_PIX_FMT_VIDEOTOOLBOX,
742 #endif
743     AV_PIX_FMT_YUV420P,
744     AV_PIX_FMT_NONE
745 };
746 
747 const AVCodecHWConfigInternal *const ff_h263_hw_config_list[] = {
748 #if CONFIG_H263_VAAPI_HWACCEL
749     HWACCEL_VAAPI(h263),
750 #endif
751 #if CONFIG_MPEG4_NVDEC_HWACCEL
752     HWACCEL_NVDEC(mpeg4),
753 #endif
754 #if CONFIG_MPEG4_VDPAU_HWACCEL
755     HWACCEL_VDPAU(mpeg4),
756 #endif
757 #if CONFIG_H263_VIDEOTOOLBOX_HWACCEL
758     HWACCEL_VIDEOTOOLBOX(h263),
759 #endif
760     NULL
761 };
762 
763 AVCodec ff_h263_decoder = {
764     .name           = "h263",
765     .long_name      = NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
766     .type           = AVMEDIA_TYPE_VIDEO,
767     .id             = AV_CODEC_ID_H263,
768     .priv_data_size = sizeof(MpegEncContext),
769     .init           = ff_h263_decode_init,
770     .close          = ff_h263_decode_end,
771     .decode         = ff_h263_decode_frame,
772     .capabilities   = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1 |
773                       AV_CODEC_CAP_TRUNCATED | AV_CODEC_CAP_DELAY,
774     .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
775     .flush          = ff_mpeg_flush,
776     .max_lowres     = 3,
777     .pix_fmts       = ff_h263_hwaccel_pixfmt_list_420,
778     .hw_configs     = ff_h263_hw_config_list,
779 };
780 
781 AVCodec ff_h263p_decoder = {
782     .name           = "h263p",
783     .long_name      = NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
784     .type           = AVMEDIA_TYPE_VIDEO,
785     .id             = AV_CODEC_ID_H263P,
786     .priv_data_size = sizeof(MpegEncContext),
787     .init           = ff_h263_decode_init,
788     .close          = ff_h263_decode_end,
789     .decode         = ff_h263_decode_frame,
790     .capabilities   = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1 |
791                       AV_CODEC_CAP_TRUNCATED | AV_CODEC_CAP_DELAY,
792     .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
793     .flush          = ff_mpeg_flush,
794     .max_lowres     = 3,
795     .pix_fmts       = ff_h263_hwaccel_pixfmt_list_420,
796     .hw_configs     = ff_h263_hw_config_list,
797 };
798