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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 "internal.h"
  32 #include "avcodec.h"
  33 #include "dsputil.h"
  34 #include "mpegvideo.h"
  35 #include "h263.h"
  36 #include "h263_parser.h"
  37 #include "mpeg4video_parser.h"
  38 #include "msmpeg4.h"
  39 #include "vdpau_internal.h"
  40 #include "thread.h"
  41 #include "flv.h"
  42 #include "mpeg4video.h"
  43
  44 //#define DEBUG
  45 //#define PRINT_FRAME_TIME
  46
  47 av_cold int ff_h263_decode_init(AVCodecContext *avctx)
  48 {
  49     MpegEncContext *s = avctx->priv_data;
  50
  51     s->avctx = avctx;
  52     s->out_format = FMT_H263;
  53
  54     s->width  = avctx->coded_width;
  55     s->height = avctx->coded_height;
  56     s->workaround_bugs= avctx->workaround_bugs;
  57
  58     // set defaults
  59     MPV_decode_defaults(s);
  60     s->quant_precision=5;
  61     s->decode_mb= ff_h263_decode_mb;
  62     s->low_delay= 1;
  63     avctx->pix_fmt= avctx->get_format(avctx, avctx->codec->pix_fmts);
  64     s->unrestricted_mv= 1;
  65
  66     /* select sub codec */
  67     switch(avctx->codec->id) {
  68     case CODEC_ID_H263:
  69         s->unrestricted_mv= 0;
  70         avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
  71         break;
  72     case CODEC_ID_MPEG4:
  73         break;
  74     case CODEC_ID_MSMPEG4V1:
  75         s->h263_pred = 1;
  76         s->msmpeg4_version=1;
  77         break;
  78     case CODEC_ID_MSMPEG4V2:
  79         s->h263_pred = 1;
  80         s->msmpeg4_version=2;
  81         break;
  82     case CODEC_ID_MSMPEG4V3:
  83         s->h263_pred = 1;
  84         s->msmpeg4_version=3;
  85         break;
  86     case CODEC_ID_WMV1:
  87         s->h263_pred = 1;
  88         s->msmpeg4_version=4;
  89         break;
  90     case CODEC_ID_WMV2:
  91         s->h263_pred = 1;
  92         s->msmpeg4_version=5;
  93         break;
  94     case CODEC_ID_VC1:
  95     case CODEC_ID_WMV3:
  96     case CODEC_ID_VC1IMAGE:
  97     case CODEC_ID_WMV3IMAGE:
  98         s->h263_pred = 1;
  99         s->msmpeg4_version=6;
 100         avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
 101         break;
 102     case CODEC_ID_H263I:
 103         break;
 104     case CODEC_ID_FLV1:
 105         s->h263_flv = 1;
 106         break;
 107     default:
 108         return -1;
 109     }
 110     s->codec_id= avctx->codec->id;
 111     avctx->hwaccel= ff_find_hwaccel(avctx->codec->id, avctx->pix_fmt);
 112
 113     /* for h263, we allocate the images after having read the header */
 114     if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
 115         if (MPV_common_init(s) < 0)
 116             return -1;
 117
 118         h263_decode_init_vlc(s);
 119
 120     return 0;
 121 }
 122
 123 av_cold int ff_h263_decode_end(AVCodecContext *avctx)
 124 {
 125     MpegEncContext *s = avctx->priv_data;
 126
 127     MPV_common_end(s);
 128     return 0;
 129 }
 130
 131 /**
 132  * Return the number of bytes consumed for building the current frame.
 133  */
 134 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
 135     int pos= (get_bits_count(&s->gb)+7)>>3;
 136
 137     if(s->divx_packed || s->avctx->hwaccel){
 138         //we would have to scan through the whole buf to handle the weird reordering ...
 139         return buf_size;
 140     }else if(s->flags&CODEC_FLAG_TRUNCATED){
 141         pos -= s->parse_context.last_index;
 142         if(pos<0) pos=0; // padding is not really read so this might be -1
 143         return pos;
 144     }else{
 145         if(pos==0) pos=1; //avoid infinite loops (i doubt that is needed but ...)
 146         if(pos+10>buf_size) pos=buf_size; // oops ;)
 147
 148         return pos;
 149     }
 150 }
 151
 152 static int decode_slice(MpegEncContext *s){
 153     const int part_mask= s->partitioned_frame ? (ER_AC_END|ER_AC_ERROR) : 0x7F;
 154     const int mb_size= 16>>s->avctx->lowres;
 155     s->last_resync_gb= s->gb;
 156     s->first_slice_line= 1;
 157
 158     s->resync_mb_x= s->mb_x;
 159     s->resync_mb_y= s->mb_y;
 160
 161     ff_set_qscale(s, s->qscale);
 162
 163     if (s->avctx->hwaccel) {
 164         const uint8_t *start= s->gb.buffer + get_bits_count(&s->gb)/8;
 165         const uint8_t *end  = ff_h263_find_resync_marker(start + 1, s->gb.buffer_end);
 166         skip_bits_long(&s->gb, 8*(end - start));
 167         return s->avctx->hwaccel->decode_slice(s->avctx, start, end - start);
 168     }
 169
 170     if(s->partitioned_frame){
 171         const int qscale= s->qscale;
 172
 173         if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
 174             if(ff_mpeg4_decode_partitions(s) < 0)
 175                 return -1;
 176         }
 177
 178         /* restore variables which were modified */
 179         s->first_slice_line=1;
 180         s->mb_x= s->resync_mb_x;
 181         s->mb_y= s->resync_mb_y;
 182         ff_set_qscale(s, qscale);
 183     }
 184
 185     for(; s->mb_y < s->mb_height; s->mb_y++) {
 186         /* per-row end of slice checks */
 187         if(s->msmpeg4_version){
 188             if(s->resync_mb_y + s->slice_height == s->mb_y){
 189                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_END);
 190
 191                 return 0;
 192             }
 193         }
 194
 195         if(s->msmpeg4_version==1){
 196             s->last_dc[0]=
 197             s->last_dc[1]=
 198             s->last_dc[2]= 128;
 199         }
 200
 201         ff_init_block_index(s);
 202         for(; s->mb_x < s->mb_width; s->mb_x++) {
 203             int ret;
 204
 205             ff_update_block_index(s);
 206
 207             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
 208                 s->first_slice_line=0;
 209             }
 210
 211             /* DCT & quantize */
 212
 213             s->mv_dir = MV_DIR_FORWARD;
 214             s->mv_type = MV_TYPE_16X16;
 215 //            s->mb_skipped = 0;
 216 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
 217             ret= s->decode_mb(s, s->block);
 218
 219             if (s->pict_type!=AV_PICTURE_TYPE_B)
 220                 ff_h263_update_motion_val(s);
 221
 222             if(ret<0){
 223                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
 224                 if(ret==SLICE_END){
 225                     MPV_decode_mb(s, s->block);
 226                     if(s->loop_filter)
 227                         ff_h263_loop_filter(s);
 228
 229 //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));
 230                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_END&part_mask);
 231
 232                     s->padding_bug_score--;
 233
 234                     if(++s->mb_x >= s->mb_width){
 235                         s->mb_x=0;
 236                         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
 237                         MPV_report_decode_progress(s);
 238                         s->mb_y++;
 239                     }
 240                     return 0;
 241                 }else if(ret==SLICE_NOEND){
 242                     av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
 243                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x+1, s->mb_y, ER_MB_END&part_mask);
 244                     return -1;
 245                 }
 246                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
 247                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_ERROR&part_mask);
 248
 249                 return -1;
 250             }
 251
 252             MPV_decode_mb(s, s->block);
 253             if(s->loop_filter)
 254                 ff_h263_loop_filter(s);
 255         }
 256
 257         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
 258         MPV_report_decode_progress(s);
 259
 260         s->mb_x= 0;
 261     }
 262
 263     assert(s->mb_x==0 && s->mb_y==s->mb_height);
 264
 265     if(s->codec_id==CODEC_ID_MPEG4
 266        && (s->workaround_bugs&FF_BUG_AUTODETECT)
 267        && get_bits_left(&s->gb) >= 48
 268        && show_bits(&s->gb, 24)==0x4010
 269        && !s->data_partitioning)
 270         s->padding_bug_score+=32;
 271
 272     /* try to detect the padding bug */
 273     if(      s->codec_id==CODEC_ID_MPEG4
 274        &&   (s->workaround_bugs&FF_BUG_AUTODETECT)
 275        &&    get_bits_left(&s->gb) >=0
 276        &&    get_bits_left(&s->gb) < 137
 277 //       &&   !s->resync_marker
 278        &&   !s->data_partitioning){
 279
 280         const int bits_count= get_bits_count(&s->gb);
 281         const int bits_left = s->gb.size_in_bits - bits_count;
 282
 283         if(bits_left==0){
 284             s->padding_bug_score+=16;
 285         } else if(bits_left != 1){
 286             int v= show_bits(&s->gb, 8);
 287             v|= 0x7F >> (7-(bits_count&7));
 288
 289             if(v==0x7F && bits_left<=8)
 290                 s->padding_bug_score--;
 291             else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
 292                 s->padding_bug_score+= 4;
 293             else
 294                 s->padding_bug_score++;
 295         }
 296     }
 297
 298     if(s->workaround_bugs&FF_BUG_AUTODETECT){
 299         if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version>=0 || !s->resync_marker)*/)
 300             s->workaround_bugs |=  FF_BUG_NO_PADDING;
 301         else
 302             s->workaround_bugs &= ~FF_BUG_NO_PADDING;
 303     }
 304
 305     // handle formats which don't have unique end markers
 306     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
 307         int left= get_bits_left(&s->gb);
 308         int max_extra=7;
 309
 310         /* no markers in M$ crap */
 311         if(s->msmpeg4_version && s->pict_type==AV_PICTURE_TYPE_I)
 312             max_extra+= 17;
 313
 314         /* buggy padding but the frame should still end approximately at the bitstream end */
 315         if((s->workaround_bugs&FF_BUG_NO_PADDING) && (s->err_recognition&(AV_EF_BUFFER|AV_EF_AGGRESSIVE)))
 316             max_extra+= 48;
 317         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
 318             max_extra+= 256*256*256*64;
 319
 320         if(left>max_extra){
 321             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
 322         }
 323         else if(left<0){
 324             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
 325         }else
 326             ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_END);
 327
 328         return 0;
 329     }
 330
 331     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
 332             get_bits_left(&s->gb),
 333             show_bits(&s->gb, 24), s->padding_bug_score);
 334
 335     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_END&part_mask);
 336
 337     return -1;
 338 }
 339
 340 int ff_h263_decode_frame(AVCodecContext *avctx,
 341                              void *data, int *data_size,
 342                              AVPacket *avpkt)
 343 {
 344     const uint8_t *buf = avpkt->data;
 345     int buf_size = avpkt->size;
 346     MpegEncContext *s = avctx->priv_data;
 347     int ret;
 348     AVFrame *pict = data;
 349
 350 #ifdef PRINT_FRAME_TIME
 351 uint64_t time= rdtsc();
 352 #endif
 353     s->flags= avctx->flags;
 354     s->flags2= avctx->flags2;
 355
 356     /* no supplementary picture */
 357     if (buf_size == 0) {
 358         /* special case for last picture */
 359         if (s->low_delay==0 && s->next_picture_ptr) {
 360             *pict= *(AVFrame*)s->next_picture_ptr;
 361             s->next_picture_ptr= NULL;
 362
 363             *data_size = sizeof(AVFrame);
 364         }
 365
 366         return 0;
 367     }
 368
 369     if(s->flags&CODEC_FLAG_TRUNCATED){
 370         int next;
 371
 372         if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
 373             next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
 374         }else if(CONFIG_H263_DECODER && s->codec_id==CODEC_ID_H263){
 375             next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
 376         }else{
 377             av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
 378             return -1;
 379         }
 380
 381         if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
 382             return buf_size;
 383     }
 384
 385
 386 retry:
 387     if(s->divx_packed && s->bitstream_buffer_size){
 388         int i;
 389         for(i=0; i<buf_size-3; i++){
 390             if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1){
 391                 if(buf[i+3]==0xB0){
 392                     av_log(s->avctx, AV_LOG_WARNING, "Discarding excessive bitstream in packed xvid\n");
 393                     s->bitstream_buffer_size=0;
 394                 }
 395                 break;
 396             }
 397         }
 398     }
 399
 400     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
 401         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
 402     }else
 403         init_get_bits(&s->gb, buf, buf_size*8);
 404     s->bitstream_buffer_size=0;
 405
 406     if (!s->context_initialized) {
 407         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
 408             return -1;
 409     }
 410
 411     /* We need to set current_picture_ptr before reading the header,
 412      * otherwise we cannot store anyting in there */
 413     if (s->current_picture_ptr == NULL || s->current_picture_ptr->f.data[0]) {
 414         int i= ff_find_unused_picture(s, 0);
 415         if (i < 0)
 416             return i;
 417         s->current_picture_ptr= &s->picture[i];
 418     }
 419
 420     /* let's go :-) */
 421     if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5) {
 422         ret= ff_wmv2_decode_picture_header(s);
 423     } else if (CONFIG_MSMPEG4_DECODER && s->msmpeg4_version) {
 424         ret = msmpeg4_decode_picture_header(s);
 425     } else if (CONFIG_MPEG4_DECODER && s->h263_pred) {
 426         if(s->avctx->extradata_size && s->picture_number==0){
 427             GetBitContext gb;
 428
 429             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
 430             ret = ff_mpeg4_decode_picture_header(s, &gb);
 431         }
 432         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
 433     } else if (CONFIG_H263I_DECODER && s->codec_id == CODEC_ID_H263I) {
 434         ret = ff_intel_h263_decode_picture_header(s);
 435     } else if (CONFIG_FLV_DECODER && s->h263_flv) {
 436         ret = ff_flv_decode_picture_header(s);
 437     } else {
 438         ret = h263_decode_picture_header(s);
 439     }
 440
 441     if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
 442
 443     /* skip if the header was thrashed */
 444     if (ret < 0){
 445         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
 446         return -1;
 447     }
 448
 449     avctx->has_b_frames= !s->low_delay;
 450
 451     if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
 452         if(s->stream_codec_tag == AV_RL32("XVID") ||
 453            s->codec_tag == AV_RL32("XVID") || s->codec_tag == AV_RL32("XVIX") ||
 454            s->codec_tag == AV_RL32("RMP4") ||
 455            s->codec_tag == AV_RL32("SIPP")
 456            )
 457             s->xvid_build= 0;
 458 #if 0
 459         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
 460            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
 461             s->xvid_build= 0;
 462 #endif
 463     }
 464
 465     if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
 466         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
 467             s->divx_version= 400; //divx 4
 468     }
 469
 470     if(s->xvid_build>=0 && s->divx_version>=0){
 471         s->divx_version=
 472         s->divx_build= -1;
 473     }
 474
 475     if(s->workaround_bugs&FF_BUG_AUTODETECT){
 476         if(s->codec_tag == AV_RL32("XVIX"))
 477             s->workaround_bugs|= FF_BUG_XVID_ILACE;
 478
 479         if(s->codec_tag == AV_RL32("UMP4")){
 480             s->workaround_bugs|= FF_BUG_UMP4;
 481         }
 482
 483         if(s->divx_version>=500 && s->divx_build<1814){
 484             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
 485         }
 486
 487         if(s->divx_version>502 && s->divx_build<1814){
 488             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
 489         }
 490
 491         if(s->xvid_build<=3U)
 492             s->padding_bug_score= 256*256*256*64;
 493
 494         if(s->xvid_build<=1U)
 495             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
 496
 497         if(s->xvid_build<=12U)
 498             s->workaround_bugs|= FF_BUG_EDGE;
 499
 500         if(s->xvid_build<=32U)
 501             s->workaround_bugs|= FF_BUG_DC_CLIP;
 502
 503 #define SET_QPEL_FUNC(postfix1, postfix2) \
 504     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
 505     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
 506     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
 507
 508         if(s->lavc_build<4653U)
 509             s->workaround_bugs|= FF_BUG_STD_QPEL;
 510
 511         if(s->lavc_build<4655U)
 512             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
 513
 514         if(s->lavc_build<4670U){
 515             s->workaround_bugs|= FF_BUG_EDGE;
 516         }
 517
 518         if(s->lavc_build<=4712U)
 519             s->workaround_bugs|= FF_BUG_DC_CLIP;
 520
 521         if(s->divx_version>=0)
 522             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
 523 //printf("padding_bug_score: %d\n", s->padding_bug_score);
 524         if(s->divx_version==501 && s->divx_build==20020416)
 525             s->padding_bug_score= 256*256*256*64;
 526
 527         if(s->divx_version<500U){
 528             s->workaround_bugs|= FF_BUG_EDGE;
 529         }
 530
 531         if(s->divx_version>=0)
 532             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
 533 #if 0
 534         if(s->divx_version==500)
 535             s->padding_bug_score= 256*256*256*64;
 536
 537         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
 538          * Let us hope this at least works.
 539          */
 540         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==-1
 541            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
 542             s->workaround_bugs|= FF_BUG_NO_PADDING;
 543
 544         if(s->lavc_build<4609U) //FIXME not sure about the version num but a 4609 file seems ok
 545             s->workaround_bugs|= FF_BUG_NO_PADDING;
 546 #endif
 547     }
 548
 549     if(s->workaround_bugs& FF_BUG_STD_QPEL){
 550         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
 551         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
 552         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
 553         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
 554         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
 555         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
 556
 557         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
 558         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
 559         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
 560         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
 561         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
 562         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
 563     }
 564
 565     if(avctx->debug & FF_DEBUG_BUGS)
 566         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
 567                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
 568                s->divx_packed ? "p" : "");
 569
 570 #if HAVE_MMX
 571     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)) {
 572         avctx->idct_algo= FF_IDCT_XVIDMMX;
 573         avctx->coded_width= 0; // force reinit
 574 //        dsputil_init(&s->dsp, avctx);
 575         s->picture_number=0;
 576     }
 577 #endif
 578
 579         /* After H263 & mpeg4 header decode we have the height, width,*/
 580         /* and other parameters. So then we could init the picture   */
 581         /* FIXME: By the way H263 decoder is evolving it should have */
 582         /* an H263EncContext                                         */
 583
 584     if (   s->width  != avctx->coded_width
 585         || s->height != avctx->coded_height) {
 586         /* H.263 could change picture size any time */
 587         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
 588         s->parse_context.buffer=0;
 589         MPV_common_end(s);
 590         s->parse_context= pc;
 591     }
 592     if (!s->context_initialized) {
 593         avcodec_set_dimensions(avctx, s->width, s->height);
 594
 595         goto retry;
 596     }
 597
 598     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P || s->codec_id == CODEC_ID_H263I))
 599         s->gob_index = ff_h263_get_gob_height(s);
 600
 601     // for skipping the frame
 602     s->current_picture.f.pict_type = s->pict_type;
 603     s->current_picture.f.key_frame = s->pict_type == AV_PICTURE_TYPE_I;
 604
 605     /* skip B-frames if we don't have reference frames */
 606     if(s->last_picture_ptr==NULL && (s->pict_type==AV_PICTURE_TYPE_B || s->dropable)) return get_consumed_bytes(s, buf_size);
 607     if(   (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==AV_PICTURE_TYPE_B)
 608        || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=AV_PICTURE_TYPE_I)
 609        ||  avctx->skip_frame >= AVDISCARD_ALL)
 610         return get_consumed_bytes(s, buf_size);
 611
 612     if(s->next_p_frame_damaged){
 613         if(s->pict_type==AV_PICTURE_TYPE_B)
 614             return get_consumed_bytes(s, buf_size);
 615         else
 616             s->next_p_frame_damaged=0;
 617     }
 618
 619     if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==AV_PICTURE_TYPE_B){
 620         s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
 621         s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
 622     }else if((!s->no_rounding) || s->pict_type==AV_PICTURE_TYPE_B){
 623         s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
 624         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
 625     }else{
 626         s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
 627         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
 628     }
 629
 630     if(MPV_frame_start(s, avctx) < 0)
 631         return -1;
 632
 633     if (!s->divx_packed) ff_thread_finish_setup(avctx);
 634
 635     if (CONFIG_MPEG4_VDPAU_DECODER && (s->avctx->codec->capabilities & CODEC_CAP_HWACCEL_VDPAU)) {
 636         ff_vdpau_mpeg4_decode_picture(s, s->gb.buffer, s->gb.buffer_end - s->gb.buffer);
 637         goto frame_end;
 638     }
 639
 640     if (avctx->hwaccel) {
 641         if (avctx->hwaccel->start_frame(avctx, s->gb.buffer, s->gb.buffer_end - s->gb.buffer) < 0)
 642             return -1;
 643     }
 644
 645     ff_er_frame_start(s);
 646
 647     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
 648     //which is not available before MPV_frame_start()
 649     if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5){
 650         ret = ff_wmv2_decode_secondary_picture_header(s);
 651         if(ret<0) return ret;
 652         if(ret==1) goto intrax8_decoded;
 653     }
 654
 655     /* decode each macroblock */
 656     s->mb_x=0;
 657     s->mb_y=0;
 658
 659     ret = decode_slice(s);
 660     while(s->mb_y<s->mb_height){
 661         if(s->msmpeg4_version){
 662             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)
 663                 break;
 664         }else{
 665             int prev_x=s->mb_x, prev_y=s->mb_y;
 666             if(ff_h263_resync(s)<0)
 667                 break;
 668             if (prev_y * s->mb_width + prev_x < s->mb_y * s->mb_width + s->mb_x)
 669                 s->error_occurred = 1;
 670         }
 671
 672         if(s->msmpeg4_version<4 && s->h263_pred)
 673             ff_mpeg4_clean_buffers(s);
 674
 675         if (decode_slice(s) < 0) ret = AVERROR_INVALIDDATA;
 676     }
 677
 678     if (s->msmpeg4_version && s->msmpeg4_version<4 && s->pict_type==AV_PICTURE_TYPE_I)
 679         if(!CONFIG_MSMPEG4_DECODER || msmpeg4_decode_ext_header(s, buf_size) < 0){
 680             s->error_status_table[s->mb_num-1]= ER_MB_ERROR;
 681         }
 682
 683     assert(s->bitstream_buffer_size==0);
 684 frame_end:
 685     /* divx 5.01+ bistream reorder stuff */
 686     if(s->codec_id==CODEC_ID_MPEG4 && s->divx_packed){
 687         int current_pos= s->gb.buffer == s->bitstream_buffer ? 0 : (get_bits_count(&s->gb)>>3);
 688         int startcode_found=0;
 689
 690         if(buf_size - current_pos > 7){
 691             int i;
 692             for(i=current_pos; i<buf_size-4; i++){
 693                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
 694                     startcode_found=!(buf[i+4]&0x40);
 695                     break;
 696                 }
 697             }
 698         }
 699
 700         if(startcode_found){
 701             av_fast_malloc(
 702                 &s->bitstream_buffer,
 703                 &s->allocated_bitstream_buffer_size,
 704                 buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
 705             if (!s->bitstream_buffer)
 706                 return AVERROR(ENOMEM);
 707             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
 708             s->bitstream_buffer_size= buf_size - current_pos;
 709         }
 710     }
 711
 712 intrax8_decoded:
 713     ff_er_frame_end(s);
 714
 715     if (avctx->hwaccel) {
 716         if (avctx->hwaccel->end_frame(avctx) < 0)
 717             return -1;
 718     }
 719
 720     MPV_frame_end(s);
 721
 722     assert(s->current_picture.f.pict_type == s->current_picture_ptr->f.pict_type);
 723     assert(s->current_picture.f.pict_type == s->pict_type);
 724     if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {
 725         *pict= *(AVFrame*)s->current_picture_ptr;
 726     } else if (s->last_picture_ptr != NULL) {
 727         *pict= *(AVFrame*)s->last_picture_ptr;
 728     }
 729
 730     if(s->last_picture_ptr || s->low_delay){
 731         *data_size = sizeof(AVFrame);
 732         ff_print_debug_info(s, pict);
 733     }
 734
 735 #ifdef PRINT_FRAME_TIME
 736 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
 737 #endif
 738
 739     return (ret && (avctx->err_recognition & AV_EF_EXPLODE))?ret:get_consumed_bytes(s, buf_size);
 740 }
 741
 742 AVCodec ff_h263_decoder = {
 743     .name           = "h263",
 744     .type           = AVMEDIA_TYPE_VIDEO,
 745     .id             = CODEC_ID_H263,
 746     .priv_data_size = sizeof(MpegEncContext),
 747     .init           = ff_h263_decode_init,
 748     .close          = ff_h263_decode_end,
 749     .decode         = ff_h263_decode_frame,
 750     .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
 751     .flush= ff_mpeg_flush,
 752     .max_lowres= 3,
 753     .long_name= NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
 754     .pix_fmts= ff_hwaccel_pixfmt_list_420,
 755 };