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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 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     ff_MPV_decode_defaults(s);
  58     s->quant_precision=5;
  59     s->decode_mb= ff_h263_decode_mb;
  60     s->low_delay= 1;
  61     if (avctx->codec->id == AV_CODEC_ID_MSS2)
  62         avctx->pix_fmt = PIX_FMT_YUV420P;
  63     else
  64         avctx->pix_fmt = avctx->get_format(avctx, avctx->codec->pix_fmts);
  65     s->unrestricted_mv= 1;
  66
  67     /* select sub codec */
  68     switch(avctx->codec->id) {
  69     case AV_CODEC_ID_H263:
  70         s->unrestricted_mv= 0;
  71         avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
  72         break;
  73     case AV_CODEC_ID_MPEG4:
  74         break;
  75     case AV_CODEC_ID_MSMPEG4V1:
  76         s->h263_pred = 1;
  77         s->msmpeg4_version=1;
  78         break;
  79     case AV_CODEC_ID_MSMPEG4V2:
  80         s->h263_pred = 1;
  81         s->msmpeg4_version=2;
  82         break;
  83     case AV_CODEC_ID_MSMPEG4V3:
  84         s->h263_pred = 1;
  85         s->msmpeg4_version=3;
  86         break;
  87     case AV_CODEC_ID_WMV1:
  88         s->h263_pred = 1;
  89         s->msmpeg4_version=4;
  90         break;
  91     case AV_CODEC_ID_WMV2:
  92         s->h263_pred = 1;
  93         s->msmpeg4_version=5;
  94         break;
  95     case AV_CODEC_ID_VC1:
  96     case AV_CODEC_ID_WMV3:
  97     case AV_CODEC_ID_VC1IMAGE:
  98     case AV_CODEC_ID_WMV3IMAGE:
  99     case AV_CODEC_ID_MSS2:
 100         s->h263_pred = 1;
 101         s->msmpeg4_version=6;
 102         avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
 103         break;
 104     case AV_CODEC_ID_H263I:
 105         break;
 106     case AV_CODEC_ID_FLV1:
 107         s->h263_flv = 1;
 108         break;
 109     default:
 110         return -1;
 111     }
 112     s->codec_id= avctx->codec->id;
 113     avctx->hwaccel= ff_find_hwaccel(avctx->codec->id, avctx->pix_fmt);
 114
 115     /* for h263, we allocate the images after having read the header */
 116     if (avctx->codec->id != AV_CODEC_ID_H263 && avctx->codec->id != AV_CODEC_ID_MPEG4)
 117         if (ff_MPV_common_init(s) < 0)
 118             return -1;
 119
 120         ff_h263_decode_init_vlc(s);
 121
 122     return 0;
 123 }
 124
 125 av_cold int ff_h263_decode_end(AVCodecContext *avctx)
 126 {
 127     MpegEncContext *s = avctx->priv_data;
 128
 129     ff_MPV_common_end(s);
 130     return 0;
 131 }
 132
 133 /**
 134  * Return the number of bytes consumed for building the current frame.
 135  */
 136 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
 137     int pos= (get_bits_count(&s->gb)+7)>>3;
 138
 139     if(s->divx_packed || s->avctx->hwaccel){
 140         //we would have to scan through the whole buf to handle the weird reordering ...
 141         return buf_size;
 142     }else if(s->flags&CODEC_FLAG_TRUNCATED){
 143         pos -= s->parse_context.last_index;
 144         if(pos<0) pos=0; // padding is not really read so this might be -1
 145         return pos;
 146     }else{
 147         if(pos==0) pos=1; //avoid infinite loops (i doubt that is needed but ...)
 148         if(pos+10>buf_size) pos=buf_size; // oops ;)
 149
 150         return pos;
 151     }
 152 }
 153
 154 static int decode_slice(MpegEncContext *s){
 155     const int part_mask= s->partitioned_frame ? (ER_AC_END|ER_AC_ERROR) : 0x7F;
 156     const int mb_size = 16;
 157     s->last_resync_gb= s->gb;
 158     s->first_slice_line= 1;
 159
 160     s->resync_mb_x= s->mb_x;
 161     s->resync_mb_y= s->mb_y;
 162
 163     ff_set_qscale(s, s->qscale);
 164
 165     if (s->avctx->hwaccel) {
 166         const uint8_t *start= s->gb.buffer + get_bits_count(&s->gb)/8;
 167         const uint8_t *end  = ff_h263_find_resync_marker(start + 1, s->gb.buffer_end);
 168         skip_bits_long(&s->gb, 8*(end - start));
 169         return s->avctx->hwaccel->decode_slice(s->avctx, start, end - start);
 170     }
 171
 172     if(s->partitioned_frame){
 173         const int qscale= s->qscale;
 174
 175         if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4){
 176             if(ff_mpeg4_decode_partitions(s) < 0)
 177                 return -1;
 178         }
 179
 180         /* restore variables which were modified */
 181         s->first_slice_line=1;
 182         s->mb_x= s->resync_mb_x;
 183         s->mb_y= s->resync_mb_y;
 184         ff_set_qscale(s, qscale);
 185     }
 186
 187     for(; s->mb_y < s->mb_height; s->mb_y++) {
 188         /* per-row end of slice checks */
 189         if(s->msmpeg4_version){
 190             if(s->resync_mb_y + s->slice_height == s->mb_y){
 191                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_END);
 192
 193                 return 0;
 194             }
 195         }
 196
 197         if(s->msmpeg4_version==1){
 198             s->last_dc[0]=
 199             s->last_dc[1]=
 200             s->last_dc[2]= 128;
 201         }
 202
 203         ff_init_block_index(s);
 204         for(; s->mb_x < s->mb_width; s->mb_x++) {
 205             int ret;
 206
 207             ff_update_block_index(s);
 208
 209             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
 210                 s->first_slice_line=0;
 211             }
 212
 213             /* DCT & quantize */
 214
 215             s->mv_dir = MV_DIR_FORWARD;
 216             s->mv_type = MV_TYPE_16X16;
 217 //            s->mb_skipped = 0;
 218             av_dlog(s, "%d %d %06X\n",
 219                     ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
 220             ret= s->decode_mb(s, s->block);
 221
 222             if (s->pict_type!=AV_PICTURE_TYPE_B)
 223                 ff_h263_update_motion_val(s);
 224
 225             if(ret<0){
 226                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
 227                 if(ret==SLICE_END){
 228                     ff_MPV_decode_mb(s, s->block);
 229                     if(s->loop_filter)
 230                         ff_h263_loop_filter(s);
 231
 232                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_END&part_mask);
 233
 234                     s->padding_bug_score--;
 235
 236                     if(++s->mb_x >= s->mb_width){
 237                         s->mb_x=0;
 238                         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
 239                         ff_MPV_report_decode_progress(s);
 240                         s->mb_y++;
 241                     }
 242                     return 0;
 243                 }else if(ret==SLICE_NOEND){
 244                     av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
 245                     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);
 246                     return -1;
 247                 }
 248                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
 249                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_ERROR&part_mask);
 250
 251                 return -1;
 252             }
 253
 254             ff_MPV_decode_mb(s, s->block);
 255             if(s->loop_filter)
 256                 ff_h263_loop_filter(s);
 257         }
 258
 259         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
 260         ff_MPV_report_decode_progress(s);
 261
 262         s->mb_x= 0;
 263     }
 264
 265     assert(s->mb_x==0 && s->mb_y==s->mb_height);
 266
 267     if(s->codec_id==AV_CODEC_ID_MPEG4
 268        && (s->workaround_bugs&FF_BUG_AUTODETECT)
 269        && get_bits_left(&s->gb) >= 48
 270        && show_bits(&s->gb, 24)==0x4010
 271        && !s->data_partitioning)
 272         s->padding_bug_score+=32;
 273
 274     /* try to detect the padding bug */
 275     if(      s->codec_id==AV_CODEC_ID_MPEG4
 276        &&   (s->workaround_bugs&FF_BUG_AUTODETECT)
 277        &&    get_bits_left(&s->gb) >=0
 278        &&    get_bits_left(&s->gb) < 48
 279 //       &&   !s->resync_marker
 280        &&   !s->data_partitioning){
 281
 282         const int bits_count= get_bits_count(&s->gb);
 283         const int bits_left = s->gb.size_in_bits - bits_count;
 284
 285         if(bits_left==0){
 286             s->padding_bug_score+=16;
 287         } else if(bits_left != 1){
 288             int v= show_bits(&s->gb, 8);
 289             v|= 0x7F >> (7-(bits_count&7));
 290
 291             if(v==0x7F && bits_left<=8)
 292                 s->padding_bug_score--;
 293             else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
 294                 s->padding_bug_score+= 4;
 295             else
 296                 s->padding_bug_score++;
 297         }
 298     }
 299
 300     if(s->workaround_bugs&FF_BUG_AUTODETECT){
 301         if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version>=0 || !s->resync_marker)*/)
 302             s->workaround_bugs |=  FF_BUG_NO_PADDING;
 303         else
 304             s->workaround_bugs &= ~FF_BUG_NO_PADDING;
 305     }
 306
 307     // handle formats which don't have unique end markers
 308     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
 309         int left= get_bits_left(&s->gb);
 310         int max_extra=7;
 311
 312         /* no markers in M$ crap */
 313         if(s->msmpeg4_version && s->pict_type==AV_PICTURE_TYPE_I)
 314             max_extra+= 17;
 315
 316         /* buggy padding but the frame should still end approximately at the bitstream end */
 317         if((s->workaround_bugs&FF_BUG_NO_PADDING) && (s->err_recognition&AV_EF_BUFFER))
 318             max_extra+= 48;
 319         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
 320             max_extra+= 256*256*256*64;
 321
 322         if(left>max_extra){
 323             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
 324         }
 325         else if(left<0){
 326             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
 327         }else
 328             ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_END);
 329
 330         return 0;
 331     }
 332
 333     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
 334             get_bits_left(&s->gb),
 335             show_bits(&s->gb, 24), s->padding_bug_score);
 336
 337     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_END&part_mask);
 338
 339     return -1;
 340 }
 341
 342 int ff_h263_decode_frame(AVCodecContext *avctx,
 343                              void *data, int *data_size,
 344                              AVPacket *avpkt)
 345 {
 346     const uint8_t *buf = avpkt->data;
 347     int buf_size = avpkt->size;
 348     MpegEncContext *s = avctx->priv_data;
 349     int ret;
 350     AVFrame *pict = data;
 351
 352 #ifdef PRINT_FRAME_TIME
 353 uint64_t time= rdtsc();
 354 #endif
 355     s->flags= avctx->flags;
 356     s->flags2= avctx->flags2;
 357
 358     /* no supplementary picture */
 359     if (buf_size == 0) {
 360         /* special case for last picture */
 361         if (s->low_delay==0 && s->next_picture_ptr) {
 362             *pict = s->next_picture_ptr->f;
 363             s->next_picture_ptr= NULL;
 364
 365             *data_size = sizeof(AVFrame);
 366         }
 367
 368         return 0;
 369     }
 370
 371     if(s->flags&CODEC_FLAG_TRUNCATED){
 372         int next;
 373
 374         if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4){
 375             next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
 376         }else if(CONFIG_H263_DECODER && s->codec_id==AV_CODEC_ID_H263){
 377             next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
 378         }else{
 379             av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
 380             return -1;
 381         }
 382
 383         if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
 384             return buf_size;
 385     }
 386
 387
 388 retry:
 389
 390     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
 391         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
 392     }else
 393         init_get_bits(&s->gb, buf, buf_size*8);
 394     s->bitstream_buffer_size=0;
 395
 396     if (!s->context_initialized) {
 397         if (ff_MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
 398             return -1;
 399     }
 400
 401     /* We need to set current_picture_ptr before reading the header,
 402      * otherwise we cannot store anyting in there */
 403     if (s->current_picture_ptr == NULL || s->current_picture_ptr->f.data[0]) {
 404         int i= ff_find_unused_picture(s, 0);
 405         if (i < 0)
 406             return i;
 407         s->current_picture_ptr= &s->picture[i];
 408     }
 409
 410     /* let's go :-) */
 411     if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5) {
 412         ret= ff_wmv2_decode_picture_header(s);
 413     } else if (CONFIG_MSMPEG4_DECODER && s->msmpeg4_version) {
 414         ret = ff_msmpeg4_decode_picture_header(s);
 415     } else if (CONFIG_MPEG4_DECODER && s->h263_pred) {
 416         if(s->avctx->extradata_size && s->picture_number==0){
 417             GetBitContext gb;
 418
 419             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
 420             ret = ff_mpeg4_decode_picture_header(s, &gb);
 421         }
 422         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
 423     } else if (CONFIG_H263I_DECODER && s->codec_id == AV_CODEC_ID_H263I) {
 424         ret = ff_intel_h263_decode_picture_header(s);
 425     } else if (CONFIG_FLV_DECODER && s->h263_flv) {
 426         ret = ff_flv_decode_picture_header(s);
 427     } else {
 428         ret = ff_h263_decode_picture_header(s);
 429     }
 430
 431     if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
 432
 433     /* skip if the header was thrashed */
 434     if (ret < 0){
 435         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
 436         return -1;
 437     }
 438
 439     avctx->has_b_frames= !s->low_delay;
 440
 441     if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
 442         if(s->stream_codec_tag == AV_RL32("XVID") ||
 443            s->codec_tag == AV_RL32("XVID") || s->codec_tag == AV_RL32("XVIX") ||
 444            s->codec_tag == AV_RL32("RMP4") ||
 445            s->codec_tag == AV_RL32("SIPP")
 446            )
 447             s->xvid_build= 0;
 448 #if 0
 449         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
 450            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
 451             s->xvid_build= 0;
 452 #endif
 453     }
 454
 455     if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
 456         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
 457             s->divx_version= 400; //divx 4
 458     }
 459
 460     if(s->xvid_build>=0 && s->divx_version>=0){
 461         s->divx_version=
 462         s->divx_build= -1;
 463     }
 464
 465     if(s->workaround_bugs&FF_BUG_AUTODETECT){
 466         if(s->codec_tag == AV_RL32("XVIX"))
 467             s->workaround_bugs|= FF_BUG_XVID_ILACE;
 468
 469         if(s->codec_tag == AV_RL32("UMP4")){
 470             s->workaround_bugs|= FF_BUG_UMP4;
 471         }
 472
 473         if(s->divx_version>=500 && s->divx_build<1814){
 474             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
 475         }
 476
 477         if(s->divx_version>502 && s->divx_build<1814){
 478             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
 479         }
 480
 481         if(s->xvid_build<=3U)
 482             s->padding_bug_score= 256*256*256*64;
 483
 484         if(s->xvid_build<=1U)
 485             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
 486
 487         if(s->xvid_build<=12U)
 488             s->workaround_bugs|= FF_BUG_EDGE;
 489
 490         if(s->xvid_build<=32U)
 491             s->workaround_bugs|= FF_BUG_DC_CLIP;
 492
 493 #define SET_QPEL_FUNC(postfix1, postfix2) \
 494     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
 495     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
 496     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
 497
 498         if(s->lavc_build<4653U)
 499             s->workaround_bugs|= FF_BUG_STD_QPEL;
 500
 501         if(s->lavc_build<4655U)
 502             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
 503
 504         if(s->lavc_build<4670U){
 505             s->workaround_bugs|= FF_BUG_EDGE;
 506         }
 507
 508         if(s->lavc_build<=4712U)
 509             s->workaround_bugs|= FF_BUG_DC_CLIP;
 510
 511         if(s->divx_version>=0)
 512             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
 513         if(s->divx_version==501 && s->divx_build==20020416)
 514             s->padding_bug_score= 256*256*256*64;
 515
 516         if(s->divx_version<500U){
 517             s->workaround_bugs|= FF_BUG_EDGE;
 518         }
 519
 520         if(s->divx_version>=0)
 521             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
 522 #if 0
 523         if(s->divx_version==500)
 524             s->padding_bug_score= 256*256*256*64;
 525
 526         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
 527          * Let us hope this at least works.
 528          */
 529         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==-1
 530            && s->codec_id==AV_CODEC_ID_MPEG4 && s->vo_type==0)
 531             s->workaround_bugs|= FF_BUG_NO_PADDING;
 532
 533         if(s->lavc_build<4609U) //FIXME not sure about the version num but a 4609 file seems ok
 534             s->workaround_bugs|= FF_BUG_NO_PADDING;
 535 #endif
 536     }
 537
 538     if(s->workaround_bugs& FF_BUG_STD_QPEL){
 539         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
 540         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
 541         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
 542         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
 543         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
 544         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
 545
 546         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
 547         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
 548         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
 549         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
 550         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
 551         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
 552     }
 553
 554     if(avctx->debug & FF_DEBUG_BUGS)
 555         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
 556                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
 557                s->divx_packed ? "p" : "");
 558
 559 #if HAVE_MMX
 560     if (s->codec_id == AV_CODEC_ID_MPEG4 && s->xvid_build>=0 && avctx->idct_algo == FF_IDCT_AUTO && (av_get_cpu_flags() & AV_CPU_FLAG_MMX)) {
 561         avctx->idct_algo= FF_IDCT_XVIDMMX;
 562         ff_dct_common_init(s);
 563         s->picture_number=0;
 564     }
 565 #endif
 566
 567         /* After H263 & mpeg4 header decode we have the height, width,*/
 568         /* and other parameters. So then we could init the picture   */
 569         /* FIXME: By the way H263 decoder is evolving it should have */
 570         /* an H263EncContext                                         */
 571
 572     if (!avctx->coded_width || !avctx->coded_height) {
 573         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
 574
 575         s->parse_context.buffer=0;
 576         ff_MPV_common_end(s);
 577         s->parse_context= pc;
 578         avcodec_set_dimensions(avctx, s->width, s->height);
 579
 580         goto retry;
 581     }
 582
 583     if (s->width  != avctx->coded_width  ||
 584         s->height != avctx->coded_height ||
 585         s->context_reinit) {
 586         /* H.263 could change picture size any time */
 587         s->context_reinit = 0;
 588
 589         avcodec_set_dimensions(avctx, s->width, s->height);
 590
 591         if ((ret = ff_MPV_common_frame_size_change(s)))
 592             return ret;
 593     }
 594
 595     if((s->codec_id==AV_CODEC_ID_H263 || s->codec_id==AV_CODEC_ID_H263P || s->codec_id == AV_CODEC_ID_H263I))
 596         s->gob_index = ff_h263_get_gob_height(s);
 597
 598     // for skipping the frame
 599     s->current_picture.f.pict_type = s->pict_type;
 600     s->current_picture.f.key_frame = s->pict_type == AV_PICTURE_TYPE_I;
 601
 602     /* skip B-frames if we don't have reference frames */
 603     if(s->last_picture_ptr==NULL && (s->pict_type==AV_PICTURE_TYPE_B || s->dropable)) return get_consumed_bytes(s, buf_size);
 604     if(   (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==AV_PICTURE_TYPE_B)
 605        || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=AV_PICTURE_TYPE_I)
 606        ||  avctx->skip_frame >= AVDISCARD_ALL)
 607         return get_consumed_bytes(s, buf_size);
 608
 609     if(s->next_p_frame_damaged){
 610         if(s->pict_type==AV_PICTURE_TYPE_B)
 611             return get_consumed_bytes(s, buf_size);
 612         else
 613             s->next_p_frame_damaged=0;
 614     }
 615
 616     if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==AV_PICTURE_TYPE_B){
 617         s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
 618         s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
 619     }else if((!s->no_rounding) || s->pict_type==AV_PICTURE_TYPE_B){
 620         s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
 621         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
 622     }else{
 623         s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
 624         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
 625     }
 626
 627     if(ff_MPV_frame_start(s, avctx) < 0)
 628         return -1;
 629
 630     if (!s->divx_packed) ff_thread_finish_setup(avctx);
 631
 632     if (CONFIG_MPEG4_VDPAU_DECODER && (s->avctx->codec->capabilities & CODEC_CAP_HWACCEL_VDPAU)) {
 633         ff_vdpau_mpeg4_decode_picture(s, s->gb.buffer, s->gb.buffer_end - s->gb.buffer);
 634         goto frame_end;
 635     }
 636
 637     if (avctx->hwaccel) {
 638         if (avctx->hwaccel->start_frame(avctx, s->gb.buffer, s->gb.buffer_end - s->gb.buffer) < 0)
 639             return -1;
 640     }
 641
 642     ff_er_frame_start(s);
 643
 644     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
 645     //which is not available before ff_MPV_frame_start()
 646     if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5){
 647         ret = ff_wmv2_decode_secondary_picture_header(s);
 648         if(ret<0) return ret;
 649         if(ret==1) goto intrax8_decoded;
 650     }
 651
 652     /* decode each macroblock */
 653     s->mb_x=0;
 654     s->mb_y=0;
 655
 656     ret = decode_slice(s);
 657     while(s->mb_y<s->mb_height){
 658         if(s->msmpeg4_version){
 659             if(s->slice_height==0 || s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_left(&s->gb)<0)
 660                 break;
 661         }else{
 662             int prev_x=s->mb_x, prev_y=s->mb_y;
 663             if(ff_h263_resync(s)<0)
 664                 break;
 665             if (prev_y * s->mb_width + prev_x < s->mb_y * s->mb_width + s->mb_x)
 666                 s->error_occurred = 1;
 667         }
 668
 669         if(s->msmpeg4_version<4 && s->h263_pred)
 670             ff_mpeg4_clean_buffers(s);
 671
 672         if (decode_slice(s) < 0) ret = AVERROR_INVALIDDATA;
 673     }
 674
 675     if (s->msmpeg4_version && s->msmpeg4_version<4 && s->pict_type==AV_PICTURE_TYPE_I)
 676         if(!CONFIG_MSMPEG4_DECODER || ff_msmpeg4_decode_ext_header(s, buf_size) < 0){
 677             s->error_status_table[s->mb_num-1]= ER_MB_ERROR;
 678         }
 679
 680     assert(s->bitstream_buffer_size==0);
 681 frame_end:
 682     /* divx 5.01+ bistream reorder stuff */
 683     if(s->codec_id==AV_CODEC_ID_MPEG4 && s->divx_packed){
 684         int current_pos= get_bits_count(&s->gb)>>3;
 685         int startcode_found=0;
 686
 687         if(buf_size - current_pos > 5){
 688             int i;
 689             for(i=current_pos; i<buf_size-3; i++){
 690                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
 691                     startcode_found=1;
 692                     break;
 693                 }
 694             }
 695         }
 696         if(s->gb.buffer == s->bitstream_buffer && buf_size>7 && s->xvid_build>=0){ //xvid style
 697             startcode_found=1;
 698             current_pos=0;
 699         }
 700
 701         if(startcode_found){
 702             av_fast_malloc(
 703                 &s->bitstream_buffer,
 704                 &s->allocated_bitstream_buffer_size,
 705                 buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
 706             if (!s->bitstream_buffer)
 707                 return AVERROR(ENOMEM);
 708             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
 709             s->bitstream_buffer_size= buf_size - current_pos;
 710         }
 711     }
 712
 713 intrax8_decoded:
 714     ff_er_frame_end(s);
 715
 716     if (avctx->hwaccel) {
 717         if (avctx->hwaccel->end_frame(avctx) < 0)
 718             return -1;
 719     }
 720
 721     ff_MPV_frame_end(s);
 722
 723     assert(s->current_picture.f.pict_type == s->current_picture_ptr->f.pict_type);
 724     assert(s->current_picture.f.pict_type == s->pict_type);
 725     if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {
 726         *pict = s->current_picture_ptr->f;
 727     } else if (s->last_picture_ptr != NULL) {
 728         *pict = s->last_picture_ptr->f;
 729     }
 730
 731     if(s->last_picture_ptr || s->low_delay){
 732         *data_size = sizeof(AVFrame);
 733         ff_print_debug_info(s, pict);
 734     }
 735
 736 #ifdef PRINT_FRAME_TIME
 737 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
 738 #endif
 739
 740     return (ret && (avctx->err_recognition & AV_EF_EXPLODE))?ret:get_consumed_bytes(s, buf_size);
 741 }
 742
 743 AVCodec ff_h263_decoder = {
 744     .name           = "h263",
 745     .type           = AVMEDIA_TYPE_VIDEO,
 746     .id             = AV_CODEC_ID_H263,
 747     .priv_data_size = sizeof(MpegEncContext),
 748     .init           = ff_h263_decode_init,
 749     .close          = ff_h263_decode_end,
 750     .decode         = ff_h263_decode_frame,
 751     .capabilities   = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
 752                       CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
 753     .flush          = ff_mpeg_flush,
 754     .long_name      = NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
 755     .pix_fmts       = ff_hwaccel_pixfmt_list_420,
 756 };