libavcodec/h263dec.c

   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 Libav.
   7  *
   8  * Libav 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  * Libav 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 Libav; 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 #include "libavutil/cpu.h"
  29 #include "internal.h"
  30 #include "avcodec.h"
  31 #include "dsputil.h"
  32 #include "mpegvideo.h"
  33 #include "h263.h"
  34 #include "h263_parser.h"
  35 #include "mpeg4video_parser.h"
  36 #include "msmpeg4.h"
  37 #include "vdpau_internal.h"
  38 #include "thread.h"
  39 #include "flv.h"
  40 #include "mpeg4video.h"
  41
  42 //#define DEBUG
  43 //#define PRINT_FRAME_TIME
  44
  45 av_cold int ff_h263_decode_init(AVCodecContext *avctx)
  46 {
  47     MpegEncContext *s = avctx->priv_data;
  48
  49     s->avctx = avctx;
  50     s->out_format = FMT_H263;
  51
  52     s->width  = avctx->coded_width;
  53     s->height = avctx->coded_height;
  54     s->workaround_bugs= avctx->workaround_bugs;
  55
  56     // set defaults
  57     MPV_decode_defaults(s);
  58     s->quant_precision=5;
  59     s->decode_mb= ff_h263_decode_mb;
  60     s->low_delay= 1;
  61     avctx->pix_fmt= avctx->get_format(avctx, avctx->codec->pix_fmts);
  62     s->unrestricted_mv= 1;
  63
  64     /* select sub codec */
  65     switch(avctx->codec->id) {
  66     case CODEC_ID_H263:
  67         s->unrestricted_mv= 0;
  68         avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
  69         break;
  70     case CODEC_ID_MPEG4:
  71         break;
  72     case CODEC_ID_MSMPEG4V1:
  73         s->h263_pred = 1;
  74         s->msmpeg4_version=1;
  75         break;
  76     case CODEC_ID_MSMPEG4V2:
  77         s->h263_pred = 1;
  78         s->msmpeg4_version=2;
  79         break;
  80     case CODEC_ID_MSMPEG4V3:
  81         s->h263_pred = 1;
  82         s->msmpeg4_version=3;
  83         break;
  84     case CODEC_ID_WMV1:
  85         s->h263_pred = 1;
  86         s->msmpeg4_version=4;
  87         break;
  88     case CODEC_ID_WMV2:
  89         s->h263_pred = 1;
  90         s->msmpeg4_version=5;
  91         break;
  92     case CODEC_ID_VC1:
  93     case CODEC_ID_WMV3:
  94     case CODEC_ID_VC1IMAGE:
  95     case CODEC_ID_WMV3IMAGE:
  96         s->h263_pred = 1;
  97         s->msmpeg4_version=6;
  98         avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
  99         break;
 100     case CODEC_ID_H263I:
 101         break;
 102     case CODEC_ID_FLV1:
 103         s->h263_flv = 1;
 104         break;
 105     default:
 106         return -1;
 107     }
 108     s->codec_id= avctx->codec->id;
 109     avctx->hwaccel= ff_find_hwaccel(avctx->codec->id, avctx->pix_fmt);
 110
 111     /* for h263, we allocate the images after having read the header */
 112     if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
 113         if (MPV_common_init(s) < 0)
 114             return -1;
 115
 116         h263_decode_init_vlc(s);
 117
 118     return 0;
 119 }
 120
 121 av_cold int ff_h263_decode_end(AVCodecContext *avctx)
 122 {
 123     MpegEncContext *s = avctx->priv_data;
 124
 125     MPV_common_end(s);
 126     return 0;
 127 }
 128
 129 /**
 130  * returns the number of bytes consumed for building the current frame
 131  */
 132 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
 133     int pos= (get_bits_count(&s->gb)+7)>>3;
 134
 135     if(s->divx_packed || s->avctx->hwaccel){
 136         //we would have to scan through the whole buf to handle the weird reordering ...
 137         return buf_size;
 138     }else if(s->flags&CODEC_FLAG_TRUNCATED){
 139         pos -= s->parse_context.last_index;
 140         if(pos<0) pos=0; // padding is not really read so this might be -1
 141         return pos;
 142     }else{
 143         if(pos==0) pos=1; //avoid infinite loops (i doubt that is needed but ...)
 144         if(pos+10>buf_size) pos=buf_size; // oops ;)
 145
 146         return pos;
 147     }
 148 }
 149
 150 static int decode_slice(MpegEncContext *s){
 151     const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
 152     const int mb_size= 16>>s->avctx->lowres;
 153     s->last_resync_gb= s->gb;
 154     s->first_slice_line= 1;
 155
 156     s->resync_mb_x= s->mb_x;
 157     s->resync_mb_y= s->mb_y;
 158
 159     ff_set_qscale(s, s->qscale);
 160
 161     if (s->avctx->hwaccel) {
 162         const uint8_t *start= s->gb.buffer + get_bits_count(&s->gb)/8;
 163         const uint8_t *end  = ff_h263_find_resync_marker(start + 1, s->gb.buffer_end);
 164         skip_bits_long(&s->gb, 8*(end - start));
 165         return s->avctx->hwaccel->decode_slice(s->avctx, start, end - start);
 166     }
 167
 168     if(s->partitioned_frame){
 169         const int qscale= s->qscale;
 170
 171         if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
 172             if(ff_mpeg4_decode_partitions(s) < 0)
 173                 return -1;
 174         }
 175
 176         /* restore variables which were modified */
 177         s->first_slice_line=1;
 178         s->mb_x= s->resync_mb_x;
 179         s->mb_y= s->resync_mb_y;
 180         ff_set_qscale(s, qscale);
 181     }
 182
 183     for(; s->mb_y < s->mb_height; s->mb_y++) {
 184         /* per-row end of slice checks */
 185         if(s->msmpeg4_version){
 186             if(s->resync_mb_y + s->slice_height == s->mb_y){
 187                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, AC_END|DC_END|MV_END);
 188
 189                 return 0;
 190             }
 191         }
 192
 193         if(s->msmpeg4_version==1){
 194             s->last_dc[0]=
 195             s->last_dc[1]=
 196             s->last_dc[2]= 128;
 197         }
 198
 199         ff_init_block_index(s);
 200         for(; s->mb_x < s->mb_width; s->mb_x++) {
 201             int ret;
 202
 203             ff_update_block_index(s);
 204
 205             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
 206                 s->first_slice_line=0;
 207             }
 208
 209             /* DCT & quantize */
 210
 211             s->mv_dir = MV_DIR_FORWARD;
 212             s->mv_type = MV_TYPE_16X16;
 213 //            s->mb_skipped = 0;
 214 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
 215             ret= s->decode_mb(s, s->block);
 216
 217             if (s->pict_type!=AV_PICTURE_TYPE_B)
 218                 ff_h263_update_motion_val(s);
 219
 220             if(ret<0){
 221                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
 222                 if(ret==SLICE_END){
 223                     MPV_decode_mb(s, s->block);
 224                     if(s->loop_filter)
 225                         ff_h263_loop_filter(s);
 226
 227 //printf("%d %d %d %06X\n", s->mb_x, s->mb_y, s->gb.size*8 - get_bits_count(&s->gb), show_bits(&s->gb, 24));
 228                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, (AC_END|DC_END|MV_END)&part_mask);
 229
 230                     s->padding_bug_score--;
 231
 232                     if(++s->mb_x >= s->mb_width){
 233                         s->mb_x=0;
 234                         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
 235                         MPV_report_decode_progress(s);
 236                         s->mb_y++;
 237                     }
 238                     return 0;
 239                 }else if(ret==SLICE_NOEND){
 240                     av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
 241                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x+1, s->mb_y, (AC_END|DC_END|MV_END)&part_mask);
 242                     return -1;
 243                 }
 244                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
 245                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, (AC_ERROR|DC_ERROR|MV_ERROR)&part_mask);
 246
 247                 return -1;
 248             }
 249
 250             MPV_decode_mb(s, s->block);
 251             if(s->loop_filter)
 252                 ff_h263_loop_filter(s);
 253         }
 254
 255         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
 256         MPV_report_decode_progress(s);
 257
 258         s->mb_x= 0;
 259     }
 260
 261     assert(s->mb_x==0 && s->mb_y==s->mb_height);
 262
 263     if(s->codec_id==CODEC_ID_MPEG4
 264        && (s->workaround_bugs&FF_BUG_AUTODETECT)
 265        && get_bits_left(&s->gb) >= 48
 266        && show_bits(&s->gb, 24)==0x4010
 267        && !s->data_partitioning)
 268         s->padding_bug_score+=32;
 269
 270     /* try to detect the padding bug */
 271     if(      s->codec_id==CODEC_ID_MPEG4
 272        &&   (s->workaround_bugs&FF_BUG_AUTODETECT)
 273        &&    get_bits_left(&s->gb) >=0
 274        &&    get_bits_left(&s->gb) < 48
 275 //       &&   !s->resync_marker
 276        &&   !s->data_partitioning){
 277
 278         const int bits_count= get_bits_count(&s->gb);
 279         const int bits_left = s->gb.size_in_bits - bits_count;
 280
 281         if(bits_left==0){
 282             s->padding_bug_score+=16;
 283         } else if(bits_left != 1){
 284             int v= show_bits(&s->gb, 8);
 285             v|= 0x7F >> (7-(bits_count&7));
 286
 287             if(v==0x7F && bits_left<=8)
 288                 s->padding_bug_score--;
 289             else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
 290                 s->padding_bug_score+= 4;
 291             else
 292                 s->padding_bug_score++;
 293         }
 294     }
 295
 296     if(s->workaround_bugs&FF_BUG_AUTODETECT){
 297         if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version>=0 || !s->resync_marker)*/)
 298             s->workaround_bugs |=  FF_BUG_NO_PADDING;
 299         else
 300             s->workaround_bugs &= ~FF_BUG_NO_PADDING;
 301     }
 302
 303     // handle formats which don't have unique end markers
 304     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
 305         int left= get_bits_left(&s->gb);
 306         int max_extra=7;
 307
 308         /* no markers in M$ crap */
 309         if(s->msmpeg4_version && s->pict_type==AV_PICTURE_TYPE_I)
 310             max_extra+= 17;
 311
 312         /* buggy padding but the frame should still end approximately at the bitstream end */
 313         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_recognition>=3)
 314             max_extra+= 48;
 315         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
 316             max_extra+= 256*256*256*64;
 317
 318         if(left>max_extra){
 319             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
 320         }
 321         else if(left<0){
 322             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
 323         }else
 324             ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, AC_END|DC_END|MV_END);
 325
 326         return 0;
 327     }
 328
 329     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
 330             get_bits_left(&s->gb),
 331             show_bits(&s->gb, 24), s->padding_bug_score);
 332
 333     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, (AC_END|DC_END|MV_END)&part_mask);
 334
 335     return -1;
 336 }
 337
 338 int ff_h263_decode_frame(AVCodecContext *avctx,
 339                              void *data, int *data_size,
 340                              AVPacket *avpkt)
 341 {
 342     const uint8_t *buf = avpkt->data;
 343     int buf_size = avpkt->size;
 344     MpegEncContext *s = avctx->priv_data;
 345     int ret;
 346     AVFrame *pict = data;
 347
 348 #ifdef PRINT_FRAME_TIME
 349 uint64_t time= rdtsc();
 350 #endif
 351     s->flags= avctx->flags;
 352     s->flags2= avctx->flags2;
 353
 354     /* no supplementary picture */
 355     if (buf_size == 0) {
 356         /* special case for last picture */
 357         if (s->low_delay==0 && s->next_picture_ptr) {
 358             *pict= *(AVFrame*)s->next_picture_ptr;
 359             s->next_picture_ptr= NULL;
 360
 361             *data_size = sizeof(AVFrame);
 362         }
 363
 364         return 0;
 365     }
 366
 367     if(s->flags&CODEC_FLAG_TRUNCATED){
 368         int next;
 369
 370         if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
 371             next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
 372         }else if(CONFIG_H263_DECODER && s->codec_id==CODEC_ID_H263){
 373             next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
 374         }else{
 375             av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
 376             return -1;
 377         }
 378
 379         if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
 380             return buf_size;
 381     }
 382
 383
 384 retry:
 385
 386     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
 387         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
 388     }else
 389         init_get_bits(&s->gb, buf, buf_size*8);
 390     s->bitstream_buffer_size=0;
 391
 392     if (!s->context_initialized) {
 393         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
 394             return -1;
 395     }
 396
 397     /* We need to set current_picture_ptr before reading the header,
 398      * otherwise we cannot store anyting in there */
 399     if (s->current_picture_ptr == NULL || s->current_picture_ptr->f.data[0]) {
 400         int i= ff_find_unused_picture(s, 0);
 401         s->current_picture_ptr= &s->picture[i];
 402     }
 403
 404     /* let's go :-) */
 405     if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5) {
 406         ret= ff_wmv2_decode_picture_header(s);
 407     } else if (CONFIG_MSMPEG4_DECODER && s->msmpeg4_version) {
 408         ret = msmpeg4_decode_picture_header(s);
 409     } else if (CONFIG_MPEG4_DECODER && s->h263_pred) {
 410         if(s->avctx->extradata_size && s->picture_number==0){
 411             GetBitContext gb;
 412
 413             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
 414             ret = ff_mpeg4_decode_picture_header(s, &gb);
 415         }
 416         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
 417     } else if (CONFIG_H263I_DECODER && s->codec_id == CODEC_ID_H263I) {
 418         ret = ff_intel_h263_decode_picture_header(s);
 419     } else if (CONFIG_FLV_DECODER && s->h263_flv) {
 420         ret = ff_flv_decode_picture_header(s);
 421     } else {
 422         ret = h263_decode_picture_header(s);
 423     }
 424
 425     if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
 426
 427     /* skip if the header was thrashed */
 428     if (ret < 0){
 429         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
 430         return -1;
 431     }
 432
 433     avctx->has_b_frames= !s->low_delay;
 434
 435     if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
 436         if(s->stream_codec_tag == AV_RL32("XVID") ||
 437            s->codec_tag == AV_RL32("XVID") || s->codec_tag == AV_RL32("XVIX") ||
 438            s->codec_tag == AV_RL32("RMP4") ||
 439            s->codec_tag == AV_RL32("SIPP")
 440            )
 441             s->xvid_build= 0;
 442 #if 0
 443         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
 444            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
 445             s->xvid_build= 0;
 446 #endif
 447     }
 448
 449     if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
 450         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
 451             s->divx_version= 400; //divx 4
 452     }
 453
 454     if(s->xvid_build>=0 && s->divx_version>=0){
 455         s->divx_version=
 456         s->divx_build= -1;
 457     }
 458
 459     if(s->workaround_bugs&FF_BUG_AUTODETECT){
 460         if(s->codec_tag == AV_RL32("XVIX"))
 461             s->workaround_bugs|= FF_BUG_XVID_ILACE;
 462
 463         if(s->codec_tag == AV_RL32("UMP4")){
 464             s->workaround_bugs|= FF_BUG_UMP4;
 465         }
 466
 467         if(s->divx_version>=500 && s->divx_build<1814){
 468             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
 469         }
 470
 471         if(s->divx_version>502 && s->divx_build<1814){
 472             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
 473         }
 474
 475         if(s->xvid_build<=3U)
 476             s->padding_bug_score= 256*256*256*64;
 477
 478         if(s->xvid_build<=1U)
 479             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
 480
 481         if(s->xvid_build<=12U)
 482             s->workaround_bugs|= FF_BUG_EDGE;
 483
 484         if(s->xvid_build<=32U)
 485             s->workaround_bugs|= FF_BUG_DC_CLIP;
 486
 487 #define SET_QPEL_FUNC(postfix1, postfix2) \
 488     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
 489     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
 490     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
 491
 492         if(s->lavc_build<4653U)
 493             s->workaround_bugs|= FF_BUG_STD_QPEL;
 494
 495         if(s->lavc_build<4655U)
 496             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
 497
 498         if(s->lavc_build<4670U){
 499             s->workaround_bugs|= FF_BUG_EDGE;
 500         }
 501
 502         if(s->lavc_build<=4712U)
 503             s->workaround_bugs|= FF_BUG_DC_CLIP;
 504
 505         if(s->divx_version>=0)
 506             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
 507 //printf("padding_bug_score: %d\n", s->padding_bug_score);
 508         if(s->divx_version==501 && s->divx_build==20020416)
 509             s->padding_bug_score= 256*256*256*64;
 510
 511         if(s->divx_version<500U){
 512             s->workaround_bugs|= FF_BUG_EDGE;
 513         }
 514
 515         if(s->divx_version>=0)
 516             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
 517 #if 0
 518         if(s->divx_version==500)
 519             s->padding_bug_score= 256*256*256*64;
 520
 521         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
 522          * Let us hope this at least works.
 523          */
 524         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==-1
 525            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
 526             s->workaround_bugs|= FF_BUG_NO_PADDING;
 527
 528         if(s->lavc_build<4609U) //FIXME not sure about the version num but a 4609 file seems ok
 529             s->workaround_bugs|= FF_BUG_NO_PADDING;
 530 #endif
 531     }
 532
 533     if(s->workaround_bugs& FF_BUG_STD_QPEL){
 534         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
 535         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
 536         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
 537         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
 538         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
 539         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
 540
 541         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
 542         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
 543         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
 544         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
 545         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
 546         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
 547     }
 548
 549     if(avctx->debug & FF_DEBUG_BUGS)
 550         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
 551                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
 552                s->divx_packed ? "p" : "");
 553
 554 #if HAVE_MMX
 555     if (s->codec_id == CODEC_ID_MPEG4 && s->xvid_build>=0 && avctx->idct_algo == FF_IDCT_AUTO && (av_get_cpu_flags() & AV_CPU_FLAG_MMX)) {
 556         avctx->idct_algo= FF_IDCT_XVIDMMX;
 557         avctx->coded_width= 0; // force reinit
 558 //        dsputil_init(&s->dsp, avctx);
 559         s->picture_number=0;
 560     }
 561 #endif
 562
 563         /* After H263 & mpeg4 header decode we have the height, width,*/
 564         /* and other parameters. So then we could init the picture   */
 565         /* FIXME: By the way H263 decoder is evolving it should have */
 566         /* an H263EncContext                                         */
 567
 568     if (   s->width  != avctx->coded_width
 569         || s->height != avctx->coded_height) {
 570         /* H.263 could change picture size any time */
 571         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
 572         s->parse_context.buffer=0;
 573         MPV_common_end(s);
 574         s->parse_context= pc;
 575     }
 576     if (!s->context_initialized) {
 577         avcodec_set_dimensions(avctx, s->width, s->height);
 578
 579         goto retry;
 580     }
 581
 582     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P || s->codec_id == CODEC_ID_H263I))
 583         s->gob_index = ff_h263_get_gob_height(s);
 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==NULL && (s->pict_type==AV_PICTURE_TYPE_B || s->dropable)) return get_consumed_bytes(s, buf_size);
 591     if(   (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==AV_PICTURE_TYPE_B)
 592        || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=AV_PICTURE_TYPE_I)
 593        ||  avctx->skip_frame >= AVDISCARD_ALL)
 594         return get_consumed_bytes(s, buf_size);
 595
 596     if(s->next_p_frame_damaged){
 597         if(s->pict_type==AV_PICTURE_TYPE_B)
 598             return get_consumed_bytes(s, buf_size);
 599         else
 600             s->next_p_frame_damaged=0;
 601     }
 602
 603     if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==AV_PICTURE_TYPE_B){
 604         s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
 605         s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
 606     }else if((!s->no_rounding) || s->pict_type==AV_PICTURE_TYPE_B){
 607         s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
 608         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
 609     }else{
 610         s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
 611         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
 612     }
 613
 614     if(MPV_frame_start(s, avctx) < 0)
 615         return -1;
 616
 617     if (!s->divx_packed) ff_thread_finish_setup(avctx);
 618
 619     if (CONFIG_MPEG4_VDPAU_DECODER && (s->avctx->codec->capabilities & CODEC_CAP_HWACCEL_VDPAU)) {
 620         ff_vdpau_mpeg4_decode_picture(s, s->gb.buffer, s->gb.buffer_end - s->gb.buffer);
 621         goto frame_end;
 622     }
 623
 624     if (avctx->hwaccel) {
 625         if (avctx->hwaccel->start_frame(avctx, s->gb.buffer, s->gb.buffer_end - s->gb.buffer) < 0)
 626             return -1;
 627     }
 628
 629     ff_er_frame_start(s);
 630
 631     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
 632     //which is not available before 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) return ret;
 636         if(ret==1) goto intrax8_decoded;
 637     }
 638
 639     /* decode each macroblock */
 640     s->mb_x=0;
 641     s->mb_y=0;
 642
 643     ret = decode_slice(s);
 644     while(s->mb_y<s->mb_height){
 645         if(s->msmpeg4_version){
 646             if(s->slice_height==0 || s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_count(&s->gb) > s->gb.size_in_bits)
 647                 break;
 648         }else{
 649             int prev_x=s->mb_x, prev_y=s->mb_y;
 650             if(ff_h263_resync(s)<0)
 651                 break;
 652             if (prev_y * s->mb_width + prev_x < s->mb_y * s->mb_width + s->mb_x)
 653                 s->error_occurred = 1;
 654         }
 655
 656         if(s->msmpeg4_version<4 && s->h263_pred)
 657             ff_mpeg4_clean_buffers(s);
 658
 659         if (decode_slice(s) < 0) ret = AVERROR_INVALIDDATA;
 660     }
 661
 662     if (s->msmpeg4_version && s->msmpeg4_version<4 && s->pict_type==AV_PICTURE_TYPE_I)
 663         if(!CONFIG_MSMPEG4_DECODER || msmpeg4_decode_ext_header(s, buf_size) < 0){
 664             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
 665         }
 666
 667     assert(s->bitstream_buffer_size==0);
 668 frame_end:
 669     /* divx 5.01+ bistream reorder stuff */
 670     if(s->codec_id==CODEC_ID_MPEG4 && s->divx_packed){
 671         int current_pos= get_bits_count(&s->gb)>>3;
 672         int startcode_found=0;
 673
 674         if(buf_size - current_pos > 5){
 675             int i;
 676             for(i=current_pos; i<buf_size-3; i++){
 677                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
 678                     startcode_found=1;
 679                     break;
 680                 }
 681             }
 682         }
 683         if(s->gb.buffer == s->bitstream_buffer && buf_size>7 && s->xvid_build>=0){ //xvid style
 684             startcode_found=1;
 685             current_pos=0;
 686         }
 687
 688         if(startcode_found){
 689             av_fast_malloc(
 690                 &s->bitstream_buffer,
 691                 &s->allocated_bitstream_buffer_size,
 692                 buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
 693             if (!s->bitstream_buffer)
 694                 return AVERROR(ENOMEM);
 695             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
 696             s->bitstream_buffer_size= buf_size - current_pos;
 697         }
 698     }
 699
 700 intrax8_decoded:
 701     ff_er_frame_end(s);
 702
 703     if (avctx->hwaccel) {
 704         if (avctx->hwaccel->end_frame(avctx) < 0)
 705             return -1;
 706     }
 707
 708     MPV_frame_end(s);
 709
 710     assert(s->current_picture.f.pict_type == s->current_picture_ptr->f.pict_type);
 711     assert(s->current_picture.f.pict_type == s->pict_type);
 712     if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {
 713         *pict= *(AVFrame*)s->current_picture_ptr;
 714     } else if (s->last_picture_ptr != NULL) {
 715         *pict= *(AVFrame*)s->last_picture_ptr;
 716     }
 717
 718     if(s->last_picture_ptr || s->low_delay){
 719         *data_size = sizeof(AVFrame);
 720         ff_print_debug_info(s, pict);
 721     }
 722
 723 #ifdef PRINT_FRAME_TIME
 724 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
 725 #endif
 726
 727     return (ret && avctx->error_recognition >= FF_ER_EXPLODE)?ret:get_consumed_bytes(s, buf_size);
 728 }
 729
 730 AVCodec ff_h263_decoder = {
 731     .name           = "h263",
 732     .type           = AVMEDIA_TYPE_VIDEO,
 733     .id             = CODEC_ID_H263,
 734     .priv_data_size = sizeof(MpegEncContext),
 735     .init           = ff_h263_decode_init,
 736     .close          = ff_h263_decode_end,
 737     .decode         = ff_h263_decode_frame,
 738     .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
 739     .flush= ff_mpeg_flush,
 740     .max_lowres= 3,
 741     .long_name= NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
 742     .pix_fmts= ff_hwaccel_pixfmt_list_420,
 743 };