libavcodec/ituh263dec.c
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00001 /*
00002  * ITU H263 bitstream decoder
00003  * Copyright (c) 2000,2001 Fabrice Bellard
00004  * H263+ support.
00005  * Copyright (c) 2001 Juan J. Sierralta P
00006  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
00007  *
00008  * This file is part of FFmpeg.
00009  *
00010  * FFmpeg is free software; you can redistribute it and/or
00011  * modify it under the terms of the GNU Lesser General Public
00012  * License as published by the Free Software Foundation; either
00013  * version 2.1 of the License, or (at your option) any later version.
00014  *
00015  * FFmpeg is distributed in the hope that it will be useful,
00016  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00017  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00018  * Lesser General Public License for more details.
00019  *
00020  * You should have received a copy of the GNU Lesser General Public
00021  * License along with FFmpeg; if not, write to the Free Software
00022  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00023  */
00024 
00030 #define UNCHECKED_BITSTREAM_READER 1
00031 
00032 //#define DEBUG
00033 #include <limits.h>
00034 
00035 #include "libavutil/mathematics.h"
00036 #include "dsputil.h"
00037 #include "avcodec.h"
00038 #include "mpegvideo.h"
00039 #include "h263.h"
00040 #include "mathops.h"
00041 #include "unary.h"
00042 #include "flv.h"
00043 #include "mpeg4video.h"
00044 
00045 //#undef NDEBUG
00046 //#include <assert.h>
00047 
00048 // The defines below define the number of bits that are read at once for
00049 // reading vlc values. Changing these may improve speed and data cache needs
00050 // be aware though that decreasing them may need the number of stages that is
00051 // passed to get_vlc* to be increased.
00052 #define MV_VLC_BITS 9
00053 #define H263_MBTYPE_B_VLC_BITS 6
00054 #define CBPC_B_VLC_BITS 3
00055 
00056 static const int h263_mb_type_b_map[15]= {
00057     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
00058     MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
00059     MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
00060                       MB_TYPE_L0                                 | MB_TYPE_16x16,
00061                       MB_TYPE_L0   | MB_TYPE_CBP                 | MB_TYPE_16x16,
00062                       MB_TYPE_L0   | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
00063                       MB_TYPE_L1                                 | MB_TYPE_16x16,
00064                       MB_TYPE_L1   | MB_TYPE_CBP                 | MB_TYPE_16x16,
00065                       MB_TYPE_L1   | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
00066                       MB_TYPE_L0L1                               | MB_TYPE_16x16,
00067                       MB_TYPE_L0L1 | MB_TYPE_CBP                 | MB_TYPE_16x16,
00068                       MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
00069     0, //stuffing
00070     MB_TYPE_INTRA4x4                | MB_TYPE_CBP,
00071     MB_TYPE_INTRA4x4                | MB_TYPE_CBP | MB_TYPE_QUANT,
00072 };
00073 
00074 void ff_h263_show_pict_info(MpegEncContext *s){
00075     if(s->avctx->debug&FF_DEBUG_PICT_INFO){
00076     av_log(s->avctx, AV_LOG_DEBUG, "qp:%d %c size:%d rnd:%d%s%s%s%s%s%s%s%s%s %d/%d\n",
00077          s->qscale, av_get_picture_type_char(s->pict_type),
00078          s->gb.size_in_bits, 1-s->no_rounding,
00079          s->obmc ? " AP" : "",
00080          s->umvplus ? " UMV" : "",
00081          s->h263_long_vectors ? " LONG" : "",
00082          s->h263_plus ? " +" : "",
00083          s->h263_aic ? " AIC" : "",
00084          s->alt_inter_vlc ? " AIV" : "",
00085          s->modified_quant ? " MQ" : "",
00086          s->loop_filter ? " LOOP" : "",
00087          s->h263_slice_structured ? " SS" : "",
00088          s->avctx->time_base.den, s->avctx->time_base.num
00089     );
00090     }
00091 }
00092 
00093 /***********************************************/
00094 /* decoding */
00095 
00096 VLC ff_h263_intra_MCBPC_vlc;
00097 VLC ff_h263_inter_MCBPC_vlc;
00098 VLC ff_h263_cbpy_vlc;
00099 static VLC mv_vlc;
00100 static VLC h263_mbtype_b_vlc;
00101 static VLC cbpc_b_vlc;
00102 
00103 /* init vlcs */
00104 
00105 /* XXX: find a better solution to handle static init */
00106 void ff_h263_decode_init_vlc(MpegEncContext *s)
00107 {
00108     static int done = 0;
00109 
00110     if (!done) {
00111         done = 1;
00112 
00113         INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
00114                  ff_h263_intra_MCBPC_bits, 1, 1,
00115                  ff_h263_intra_MCBPC_code, 1, 1, 72);
00116         INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
00117                  ff_h263_inter_MCBPC_bits, 1, 1,
00118                  ff_h263_inter_MCBPC_code, 1, 1, 198);
00119         INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
00120                  &ff_h263_cbpy_tab[0][1], 2, 1,
00121                  &ff_h263_cbpy_tab[0][0], 2, 1, 64);
00122         INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
00123                  &ff_mvtab[0][1], 2, 1,
00124                  &ff_mvtab[0][0], 2, 1, 538);
00125         ff_init_rl(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
00126         ff_init_rl(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
00127         INIT_VLC_RL(ff_h263_rl_inter, 554);
00128         INIT_VLC_RL(ff_rl_intra_aic, 554);
00129         INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
00130                  &ff_h263_mbtype_b_tab[0][1], 2, 1,
00131                  &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
00132         INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
00133                  &ff_cbpc_b_tab[0][1], 2, 1,
00134                  &ff_cbpc_b_tab[0][0], 2, 1, 8);
00135     }
00136 }
00137 
00138 int ff_h263_decode_mba(MpegEncContext *s)
00139 {
00140     int i, mb_pos;
00141 
00142     for(i=0; i<6; i++){
00143         if(s->mb_num-1 <= ff_mba_max[i]) break;
00144     }
00145     mb_pos= get_bits(&s->gb, ff_mba_length[i]);
00146     s->mb_x= mb_pos % s->mb_width;
00147     s->mb_y= mb_pos / s->mb_width;
00148 
00149     return mb_pos;
00150 }
00151 
00156 static int h263_decode_gob_header(MpegEncContext *s)
00157 {
00158     unsigned int val, gob_number;
00159     int left;
00160 
00161     /* Check for GOB Start Code */
00162     val = show_bits(&s->gb, 16);
00163     if(val)
00164         return -1;
00165 
00166         /* We have a GBSC probably with GSTUFF */
00167     skip_bits(&s->gb, 16); /* Drop the zeros */
00168     left= get_bits_left(&s->gb);
00169     //MN: we must check the bits left or we might end in a infinite loop (or segfault)
00170     for(;left>13; left--){
00171         if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
00172     }
00173     if(left<=13)
00174         return -1;
00175 
00176     if(s->h263_slice_structured){
00177         if(get_bits1(&s->gb)==0)
00178             return -1;
00179 
00180         ff_h263_decode_mba(s);
00181 
00182         if(s->mb_num > 1583)
00183             if(get_bits1(&s->gb)==0)
00184                 return -1;
00185 
00186         s->qscale = get_bits(&s->gb, 5); /* SQUANT */
00187         if(get_bits1(&s->gb)==0)
00188             return -1;
00189         skip_bits(&s->gb, 2); /* GFID */
00190     }else{
00191         gob_number = get_bits(&s->gb, 5); /* GN */
00192         s->mb_x= 0;
00193         s->mb_y= s->gob_index* gob_number;
00194         skip_bits(&s->gb, 2); /* GFID */
00195         s->qscale = get_bits(&s->gb, 5); /* GQUANT */
00196     }
00197 
00198     if(s->mb_y >= s->mb_height)
00199         return -1;
00200 
00201     if(s->qscale==0)
00202         return -1;
00203 
00204     return 0;
00205 }
00206 
00213 const uint8_t *ff_h263_find_resync_marker(const uint8_t *restrict p, const uint8_t * restrict end)
00214 {
00215     assert(p < end);
00216 
00217     end-=2;
00218     p++;
00219     for(;p<end; p+=2){
00220         if(!*p){
00221             if     (!p[-1] && p[1]) return p - 1;
00222             else if(!p[ 1] && p[2]) return p;
00223         }
00224     }
00225     return end+2;
00226 }
00227 
00232 int ff_h263_resync(MpegEncContext *s){
00233     int left, pos, ret;
00234 
00235     if(s->codec_id==CODEC_ID_MPEG4){
00236         skip_bits1(&s->gb);
00237         align_get_bits(&s->gb);
00238     }
00239 
00240     if(show_bits(&s->gb, 16)==0){
00241         pos= get_bits_count(&s->gb);
00242         if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4)
00243             ret= mpeg4_decode_video_packet_header(s);
00244         else
00245             ret= h263_decode_gob_header(s);
00246         if(ret>=0)
00247             return pos;
00248     }
00249     //OK, it's not where it is supposed to be ...
00250     s->gb= s->last_resync_gb;
00251     align_get_bits(&s->gb);
00252     left= get_bits_left(&s->gb);
00253 
00254     for(;left>16+1+5+5; left-=8){
00255         if(show_bits(&s->gb, 16)==0){
00256             GetBitContext bak= s->gb;
00257 
00258             pos= get_bits_count(&s->gb);
00259             if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4)
00260                 ret= mpeg4_decode_video_packet_header(s);
00261             else
00262                 ret= h263_decode_gob_header(s);
00263             if(ret>=0)
00264                 return pos;
00265 
00266             s->gb= bak;
00267         }
00268         skip_bits(&s->gb, 8);
00269     }
00270 
00271     return -1;
00272 }
00273 
00274 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
00275 {
00276     int code, val, sign, shift;
00277     code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
00278 
00279     if (code == 0)
00280         return pred;
00281     if (code < 0)
00282         return 0xffff;
00283 
00284     sign = get_bits1(&s->gb);
00285     shift = f_code - 1;
00286     val = code;
00287     if (shift) {
00288         val = (val - 1) << shift;
00289         val |= get_bits(&s->gb, shift);
00290         val++;
00291     }
00292     if (sign)
00293         val = -val;
00294     val += pred;
00295 
00296     /* modulo decoding */
00297     if (!s->h263_long_vectors) {
00298         val = sign_extend(val, 5 + f_code);
00299     } else {
00300         /* horrible h263 long vector mode */
00301         if (pred < -31 && val < -63)
00302             val += 64;
00303         if (pred > 32 && val > 63)
00304             val -= 64;
00305 
00306     }
00307     return val;
00308 }
00309 
00310 
00311 /* Decode RVLC of H.263+ UMV */
00312 static int h263p_decode_umotion(MpegEncContext * s, int pred)
00313 {
00314    int code = 0, sign;
00315 
00316    if (get_bits1(&s->gb)) /* Motion difference = 0 */
00317       return pred;
00318 
00319    code = 2 + get_bits1(&s->gb);
00320 
00321    while (get_bits1(&s->gb))
00322    {
00323       code <<= 1;
00324       code += get_bits1(&s->gb);
00325    }
00326    sign = code & 1;
00327    code >>= 1;
00328 
00329    code = (sign) ? (pred - code) : (pred + code);
00330    av_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
00331    return code;
00332 
00333 }
00334 
00338 static void preview_obmc(MpegEncContext *s){
00339     GetBitContext gb= s->gb;
00340 
00341     int cbpc, i, pred_x, pred_y, mx, my;
00342     int16_t *mot_val;
00343     const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
00344     const int stride= s->b8_stride*2;
00345 
00346     for(i=0; i<4; i++)
00347         s->block_index[i]+= 2;
00348     for(i=4; i<6; i++)
00349         s->block_index[i]+= 1;
00350     s->mb_x++;
00351 
00352     assert(s->pict_type == AV_PICTURE_TYPE_P);
00353 
00354     do{
00355         if (get_bits1(&s->gb)) {
00356             /* skip mb */
00357             mot_val = s->current_picture.f.motion_val[0][s->block_index[0]];
00358             mot_val[0       ]= mot_val[2       ]=
00359             mot_val[0+stride]= mot_val[2+stride]= 0;
00360             mot_val[1       ]= mot_val[3       ]=
00361             mot_val[1+stride]= mot_val[3+stride]= 0;
00362 
00363             s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
00364             goto end;
00365         }
00366         cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
00367     }while(cbpc == 20);
00368 
00369     if(cbpc & 4){
00370         s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
00371     }else{
00372         get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
00373         if (cbpc & 8) {
00374             if(s->modified_quant){
00375                 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
00376                 else                  skip_bits(&s->gb, 5);
00377             }else
00378                 skip_bits(&s->gb, 2);
00379         }
00380 
00381         if ((cbpc & 16) == 0) {
00382                 s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
00383                 /* 16x16 motion prediction */
00384                 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
00385                 if (s->umvplus)
00386                    mx = h263p_decode_umotion(s, pred_x);
00387                 else
00388                    mx = ff_h263_decode_motion(s, pred_x, 1);
00389 
00390                 if (s->umvplus)
00391                    my = h263p_decode_umotion(s, pred_y);
00392                 else
00393                    my = ff_h263_decode_motion(s, pred_y, 1);
00394 
00395                 mot_val[0       ]= mot_val[2       ]=
00396                 mot_val[0+stride]= mot_val[2+stride]= mx;
00397                 mot_val[1       ]= mot_val[3       ]=
00398                 mot_val[1+stride]= mot_val[3+stride]= my;
00399         } else {
00400             s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
00401             for(i=0;i<4;i++) {
00402                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
00403                 if (s->umvplus)
00404                   mx = h263p_decode_umotion(s, pred_x);
00405                 else
00406                   mx = ff_h263_decode_motion(s, pred_x, 1);
00407 
00408                 if (s->umvplus)
00409                   my = h263p_decode_umotion(s, pred_y);
00410                 else
00411                   my = ff_h263_decode_motion(s, pred_y, 1);
00412                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
00413                   skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
00414                 mot_val[0] = mx;
00415                 mot_val[1] = my;
00416             }
00417         }
00418     }
00419 end:
00420 
00421     for(i=0; i<4; i++)
00422         s->block_index[i]-= 2;
00423     for(i=4; i<6; i++)
00424         s->block_index[i]-= 1;
00425     s->mb_x--;
00426 
00427     s->gb= gb;
00428 }
00429 
00430 static void h263_decode_dquant(MpegEncContext *s){
00431     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
00432 
00433     if(s->modified_quant){
00434         if(get_bits1(&s->gb))
00435             s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
00436         else
00437             s->qscale= get_bits(&s->gb, 5);
00438     }else
00439         s->qscale += quant_tab[get_bits(&s->gb, 2)];
00440     ff_set_qscale(s, s->qscale);
00441 }
00442 
00443 static int h263_decode_block(MpegEncContext * s, DCTELEM * block,
00444                              int n, int coded)
00445 {
00446     int code, level, i, j, last, run;
00447     RLTable *rl = &ff_h263_rl_inter;
00448     const uint8_t *scan_table;
00449     GetBitContext gb= s->gb;
00450 
00451     scan_table = s->intra_scantable.permutated;
00452     if (s->h263_aic && s->mb_intra) {
00453         rl = &ff_rl_intra_aic;
00454         i = 0;
00455         if (s->ac_pred) {
00456             if (s->h263_aic_dir)
00457                 scan_table = s->intra_v_scantable.permutated; /* left */
00458             else
00459                 scan_table = s->intra_h_scantable.permutated; /* top */
00460         }
00461     } else if (s->mb_intra) {
00462         /* DC coef */
00463         if(s->codec_id == CODEC_ID_RV10){
00464 #if CONFIG_RV10_DECODER
00465           if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
00466             int component, diff;
00467             component = (n <= 3 ? 0 : n - 4 + 1);
00468             level = s->last_dc[component];
00469             if (s->rv10_first_dc_coded[component]) {
00470                 diff = rv_decode_dc(s, n);
00471                 if (diff == 0xffff)
00472                     return -1;
00473                 level += diff;
00474                 level = level & 0xff; /* handle wrap round */
00475                 s->last_dc[component] = level;
00476             } else {
00477                 s->rv10_first_dc_coded[component] = 1;
00478             }
00479           } else {
00480                 level = get_bits(&s->gb, 8);
00481                 if (level == 255)
00482                     level = 128;
00483           }
00484 #endif
00485         }else{
00486             level = get_bits(&s->gb, 8);
00487             if((level&0x7F) == 0){
00488                 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
00489                 if(s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
00490                     return -1;
00491             }
00492             if (level == 255)
00493                 level = 128;
00494         }
00495         block[0] = level;
00496         i = 1;
00497     } else {
00498         i = 0;
00499     }
00500     if (!coded) {
00501         if (s->mb_intra && s->h263_aic)
00502             goto not_coded;
00503         s->block_last_index[n] = i - 1;
00504         return 0;
00505     }
00506 retry:
00507     for(;;) {
00508         code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
00509         if (code < 0){
00510             av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
00511             return -1;
00512         }
00513         if (code == rl->n) {
00514             /* escape */
00515             if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
00516                 ff_flv2_decode_ac_esc(&s->gb, &level, &run, &last);
00517             } else {
00518                 last = get_bits1(&s->gb);
00519                 run = get_bits(&s->gb, 6);
00520                 level = (int8_t)get_bits(&s->gb, 8);
00521                 if(level == -128){
00522                     if (s->codec_id == CODEC_ID_RV10) {
00523                         /* XXX: should patch encoder too */
00524                         level = get_sbits(&s->gb, 12);
00525                     }else{
00526                         level = get_bits(&s->gb, 5);
00527                         level |= get_sbits(&s->gb, 6)<<5;
00528                     }
00529                 }
00530             }
00531         } else {
00532             run = rl->table_run[code];
00533             level = rl->table_level[code];
00534             last = code >= rl->last;
00535             if (get_bits1(&s->gb))
00536                 level = -level;
00537         }
00538         i += run;
00539         if (i >= 64){
00540             if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
00541                 //Looks like a hack but no, it's the way it is supposed to work ...
00542                 rl = &ff_rl_intra_aic;
00543                 i = 0;
00544                 s->gb= gb;
00545                 s->dsp.clear_block(block);
00546                 goto retry;
00547             }
00548             av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
00549             return -1;
00550         }
00551         j = scan_table[i];
00552         block[j] = level;
00553         if (last)
00554             break;
00555         i++;
00556     }
00557 not_coded:
00558     if (s->mb_intra && s->h263_aic) {
00559         ff_h263_pred_acdc(s, block, n);
00560         i = 63;
00561     }
00562     s->block_last_index[n] = i;
00563     return 0;
00564 }
00565 
00566 static int h263_skip_b_part(MpegEncContext *s, int cbp)
00567 {
00568     LOCAL_ALIGNED_16(DCTELEM, dblock, [64]);
00569     int i, mbi;
00570 
00571     /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
00572      * but real value should be restored in order to be used later (in OBMC condition)
00573      */
00574     mbi = s->mb_intra;
00575     s->mb_intra = 0;
00576     for (i = 0; i < 6; i++) {
00577         if (h263_decode_block(s, dblock, i, cbp&32) < 0)
00578             return -1;
00579         cbp+=cbp;
00580     }
00581     s->mb_intra = mbi;
00582     return 0;
00583 }
00584 
00585 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
00586 {
00587     int c, mv = 1;
00588 
00589     if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
00590         c = get_bits1(gb);
00591         if (pb_frame == 2 && c)
00592             mv = !get_bits1(gb);
00593     } else { // h.263 Annex M improved PB-frame
00594         mv = get_unary(gb, 0, 4) + 1;
00595         c = mv & 1;
00596         mv = !!(mv & 2);
00597     }
00598     if(c)
00599         *cbpb = get_bits(gb, 6);
00600     return mv;
00601 }
00602 
00603 int ff_h263_decode_mb(MpegEncContext *s,
00604                       DCTELEM block[6][64])
00605 {
00606     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
00607     int16_t *mot_val;
00608     const int xy= s->mb_x + s->mb_y * s->mb_stride;
00609     int cbpb = 0, pb_mv_count = 0;
00610 
00611     assert(!s->h263_pred);
00612 
00613     if (s->pict_type == AV_PICTURE_TYPE_P) {
00614         do{
00615             if (get_bits1(&s->gb)) {
00616                 /* skip mb */
00617                 s->mb_intra = 0;
00618                 for(i=0;i<6;i++)
00619                     s->block_last_index[i] = -1;
00620                 s->mv_dir = MV_DIR_FORWARD;
00621                 s->mv_type = MV_TYPE_16X16;
00622                 s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
00623                 s->mv[0][0][0] = 0;
00624                 s->mv[0][0][1] = 0;
00625                 s->mb_skipped = !(s->obmc | s->loop_filter);
00626                 goto end;
00627             }
00628             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
00629             if (cbpc < 0){
00630                 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
00631                 return -1;
00632             }
00633         }while(cbpc == 20);
00634 
00635         s->dsp.clear_blocks(s->block[0]);
00636 
00637         dquant = cbpc & 8;
00638         s->mb_intra = ((cbpc & 4) != 0);
00639         if (s->mb_intra) goto intra;
00640 
00641         if(s->pb_frame && get_bits1(&s->gb))
00642             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
00643         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
00644 
00645         if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
00646             cbpy ^= 0xF;
00647 
00648         cbp = (cbpc & 3) | (cbpy << 2);
00649         if (dquant) {
00650             h263_decode_dquant(s);
00651         }
00652 
00653         s->mv_dir = MV_DIR_FORWARD;
00654         if ((cbpc & 16) == 0) {
00655             s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
00656             /* 16x16 motion prediction */
00657             s->mv_type = MV_TYPE_16X16;
00658             ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
00659             if (s->umvplus)
00660                mx = h263p_decode_umotion(s, pred_x);
00661             else
00662                mx = ff_h263_decode_motion(s, pred_x, 1);
00663 
00664             if (mx >= 0xffff)
00665                 return -1;
00666 
00667             if (s->umvplus)
00668                my = h263p_decode_umotion(s, pred_y);
00669             else
00670                my = ff_h263_decode_motion(s, pred_y, 1);
00671 
00672             if (my >= 0xffff)
00673                 return -1;
00674             s->mv[0][0][0] = mx;
00675             s->mv[0][0][1] = my;
00676 
00677             if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
00678                skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
00679         } else {
00680             s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
00681             s->mv_type = MV_TYPE_8X8;
00682             for(i=0;i<4;i++) {
00683                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
00684                 if (s->umvplus)
00685                   mx = h263p_decode_umotion(s, pred_x);
00686                 else
00687                   mx = ff_h263_decode_motion(s, pred_x, 1);
00688                 if (mx >= 0xffff)
00689                     return -1;
00690 
00691                 if (s->umvplus)
00692                   my = h263p_decode_umotion(s, pred_y);
00693                 else
00694                   my = ff_h263_decode_motion(s, pred_y, 1);
00695                 if (my >= 0xffff)
00696                     return -1;
00697                 s->mv[0][i][0] = mx;
00698                 s->mv[0][i][1] = my;
00699                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
00700                   skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
00701                 mot_val[0] = mx;
00702                 mot_val[1] = my;
00703             }
00704         }
00705     } else if(s->pict_type==AV_PICTURE_TYPE_B) {
00706         int mb_type;
00707         const int stride= s->b8_stride;
00708         int16_t *mot_val0 = s->current_picture.f.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
00709         int16_t *mot_val1 = s->current_picture.f.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
00710 //        const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
00711 
00712         //FIXME ugly
00713         mot_val0[0       ]= mot_val0[2       ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
00714         mot_val0[1       ]= mot_val0[3       ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
00715         mot_val1[0       ]= mot_val1[2       ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
00716         mot_val1[1       ]= mot_val1[3       ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
00717 
00718         do{
00719             mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
00720             if (mb_type < 0){
00721                 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
00722                 return -1;
00723             }
00724 
00725             mb_type= h263_mb_type_b_map[ mb_type ];
00726         }while(!mb_type);
00727 
00728         s->mb_intra = IS_INTRA(mb_type);
00729         if(HAS_CBP(mb_type)){
00730             s->dsp.clear_blocks(s->block[0]);
00731             cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
00732             if(s->mb_intra){
00733                 dquant = IS_QUANT(mb_type);
00734                 goto intra;
00735             }
00736 
00737             cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
00738 
00739             if (cbpy < 0){
00740                 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
00741                 return -1;
00742             }
00743 
00744             if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
00745                 cbpy ^= 0xF;
00746 
00747             cbp = (cbpc & 3) | (cbpy << 2);
00748         }else
00749             cbp=0;
00750 
00751         assert(!s->mb_intra);
00752 
00753         if(IS_QUANT(mb_type)){
00754             h263_decode_dquant(s);
00755         }
00756 
00757         if(IS_DIRECT(mb_type)){
00758             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
00759             mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
00760         }else{
00761             s->mv_dir = 0;
00762             s->mv_type= MV_TYPE_16X16;
00763 //FIXME UMV
00764 
00765             if(USES_LIST(mb_type, 0)){
00766                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
00767                 s->mv_dir = MV_DIR_FORWARD;
00768 
00769                 mx = ff_h263_decode_motion(s, mx, 1);
00770                 my = ff_h263_decode_motion(s, my, 1);
00771 
00772                 s->mv[0][0][0] = mx;
00773                 s->mv[0][0][1] = my;
00774                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
00775                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
00776             }
00777 
00778             if(USES_LIST(mb_type, 1)){
00779                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
00780                 s->mv_dir |= MV_DIR_BACKWARD;
00781 
00782                 mx = ff_h263_decode_motion(s, mx, 1);
00783                 my = ff_h263_decode_motion(s, my, 1);
00784 
00785                 s->mv[1][0][0] = mx;
00786                 s->mv[1][0][1] = my;
00787                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
00788                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
00789             }
00790         }
00791 
00792         s->current_picture.f.mb_type[xy] = mb_type;
00793     } else { /* I-Frame */
00794         do{
00795             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
00796             if (cbpc < 0){
00797                 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
00798                 return -1;
00799             }
00800         }while(cbpc == 8);
00801 
00802         s->dsp.clear_blocks(s->block[0]);
00803 
00804         dquant = cbpc & 4;
00805         s->mb_intra = 1;
00806 intra:
00807         s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
00808         if (s->h263_aic) {
00809             s->ac_pred = get_bits1(&s->gb);
00810             if(s->ac_pred){
00811                 s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
00812 
00813                 s->h263_aic_dir = get_bits1(&s->gb);
00814             }
00815         }else
00816             s->ac_pred = 0;
00817 
00818         if(s->pb_frame && get_bits1(&s->gb))
00819             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
00820         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
00821         if(cbpy<0){
00822             av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
00823             return -1;
00824         }
00825         cbp = (cbpc & 3) | (cbpy << 2);
00826         if (dquant) {
00827             h263_decode_dquant(s);
00828         }
00829 
00830         pb_mv_count += !!s->pb_frame;
00831     }
00832 
00833     while(pb_mv_count--){
00834         ff_h263_decode_motion(s, 0, 1);
00835         ff_h263_decode_motion(s, 0, 1);
00836     }
00837 
00838     /* decode each block */
00839     for (i = 0; i < 6; i++) {
00840         if (h263_decode_block(s, block[i], i, cbp&32) < 0)
00841             return -1;
00842         cbp+=cbp;
00843     }
00844 
00845     if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
00846         return -1;
00847     if(s->obmc && !s->mb_intra){
00848         if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
00849             preview_obmc(s);
00850     }
00851 end:
00852 
00853         /* per-MB end of slice check */
00854     {
00855         int v= show_bits(&s->gb, 16);
00856 
00857         if (get_bits_left(&s->gb) < 16) {
00858             v >>= 16 - get_bits_left(&s->gb);
00859         }
00860 
00861         if(v==0)
00862             return SLICE_END;
00863     }
00864 
00865     return SLICE_OK;
00866 }
00867 
00868 /* most is hardcoded. should extend to handle all h263 streams */
00869 int ff_h263_decode_picture_header(MpegEncContext *s)
00870 {
00871     int format, width, height, i;
00872     uint32_t startcode;
00873 
00874     align_get_bits(&s->gb);
00875 
00876     startcode= get_bits(&s->gb, 22-8);
00877 
00878     for(i= get_bits_left(&s->gb); i>24; i-=8) {
00879         startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
00880 
00881         if(startcode == 0x20)
00882             break;
00883     }
00884 
00885     if (startcode != 0x20) {
00886         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
00887         return -1;
00888     }
00889     /* temporal reference */
00890     i = get_bits(&s->gb, 8); /* picture timestamp */
00891     if( (s->picture_number&~0xFF)+i < s->picture_number)
00892         i+= 256;
00893     s->current_picture_ptr->f.pts =
00894     s->picture_number= (s->picture_number&~0xFF) + i;
00895 
00896     /* PTYPE starts here */
00897     if (get_bits1(&s->gb) != 1) {
00898         /* marker */
00899         av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
00900         return -1;
00901     }
00902     if (get_bits1(&s->gb) != 0) {
00903         av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
00904         return -1;      /* h263 id */
00905     }
00906     skip_bits1(&s->gb);         /* split screen off */
00907     skip_bits1(&s->gb);         /* camera  off */
00908     skip_bits1(&s->gb);         /* freeze picture release off */
00909 
00910     format = get_bits(&s->gb, 3);
00911     /*
00912         0    forbidden
00913         1    sub-QCIF
00914         10   QCIF
00915         7       extended PTYPE (PLUSPTYPE)
00916     */
00917 
00918     if (format != 7 && format != 6) {
00919         s->h263_plus = 0;
00920         /* H.263v1 */
00921         width = ff_h263_format[format][0];
00922         height = ff_h263_format[format][1];
00923         if (!width)
00924             return -1;
00925 
00926         s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
00927 
00928         s->h263_long_vectors = get_bits1(&s->gb);
00929 
00930         if (get_bits1(&s->gb) != 0) {
00931             av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
00932             return -1; /* SAC: off */
00933         }
00934         s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
00935         s->unrestricted_mv = s->h263_long_vectors || s->obmc;
00936 
00937         s->pb_frame = get_bits1(&s->gb);
00938         s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
00939         skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
00940 
00941         s->width = width;
00942         s->height = height;
00943         s->avctx->sample_aspect_ratio= (AVRational){12,11};
00944         s->avctx->time_base= (AVRational){1001, 30000};
00945     } else {
00946         int ufep;
00947 
00948         /* H.263v2 */
00949         s->h263_plus = 1;
00950         ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
00951 
00952         /* ufep other than 0 and 1 are reserved */
00953         if (ufep == 1) {
00954             /* OPPTYPE */
00955             format = get_bits(&s->gb, 3);
00956             av_dlog(s->avctx, "ufep=1, format: %d\n", format);
00957             s->custom_pcf= get_bits1(&s->gb);
00958             s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
00959             if (get_bits1(&s->gb) != 0) {
00960                 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
00961             }
00962             s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
00963             s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
00964             s->loop_filter= get_bits1(&s->gb);
00965             s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
00966             if(s->avctx->lowres)
00967                 s->loop_filter = 0;
00968 
00969             s->h263_slice_structured= get_bits1(&s->gb);
00970             if (get_bits1(&s->gb) != 0) {
00971                 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
00972             }
00973             if (get_bits1(&s->gb) != 0) {
00974                 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
00975             }
00976             s->alt_inter_vlc= get_bits1(&s->gb);
00977             s->modified_quant= get_bits1(&s->gb);
00978             if(s->modified_quant)
00979                 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
00980 
00981             skip_bits(&s->gb, 1); /* Prevent start code emulation */
00982 
00983             skip_bits(&s->gb, 3); /* Reserved */
00984         } else if (ufep != 0) {
00985             av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
00986             return -1;
00987         }
00988 
00989         /* MPPTYPE */
00990         s->pict_type = get_bits(&s->gb, 3);
00991         switch(s->pict_type){
00992         case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
00993         case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
00994         case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
00995         case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
00996         case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
00997         default:
00998             return -1;
00999         }
01000         skip_bits(&s->gb, 2);
01001         s->no_rounding = get_bits1(&s->gb);
01002         skip_bits(&s->gb, 4);
01003 
01004         /* Get the picture dimensions */
01005         if (ufep) {
01006             if (format == 6) {
01007                 /* Custom Picture Format (CPFMT) */
01008                 s->aspect_ratio_info = get_bits(&s->gb, 4);
01009                 av_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
01010                 /* aspect ratios:
01011                 0 - forbidden
01012                 1 - 1:1
01013                 2 - 12:11 (CIF 4:3)
01014                 3 - 10:11 (525-type 4:3)
01015                 4 - 16:11 (CIF 16:9)
01016                 5 - 40:33 (525-type 16:9)
01017                 6-14 - reserved
01018                 */
01019                 width = (get_bits(&s->gb, 9) + 1) * 4;
01020                 skip_bits1(&s->gb);
01021                 height = get_bits(&s->gb, 9) * 4;
01022                 av_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
01023                 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
01024                     /* aspected dimensions */
01025                     s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
01026                     s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
01027                 }else{
01028                     s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
01029                 }
01030             } else {
01031                 width = ff_h263_format[format][0];
01032                 height = ff_h263_format[format][1];
01033                 s->avctx->sample_aspect_ratio= (AVRational){12,11};
01034             }
01035             if ((width == 0) || (height == 0))
01036                 return -1;
01037             s->width = width;
01038             s->height = height;
01039 
01040             if(s->custom_pcf){
01041                 int gcd;
01042                 s->avctx->time_base.den= 1800000;
01043                 s->avctx->time_base.num= 1000 + get_bits1(&s->gb);
01044                 s->avctx->time_base.num*= get_bits(&s->gb, 7);
01045                 if(s->avctx->time_base.num == 0){
01046                     av_log(s, AV_LOG_ERROR, "zero framerate\n");
01047                     return -1;
01048                 }
01049                 gcd= av_gcd(s->avctx->time_base.den, s->avctx->time_base.num);
01050                 s->avctx->time_base.den /= gcd;
01051                 s->avctx->time_base.num /= gcd;
01052             }else{
01053                 s->avctx->time_base= (AVRational){1001, 30000};
01054             }
01055         }
01056 
01057         if(s->custom_pcf){
01058             skip_bits(&s->gb, 2); //extended Temporal reference
01059         }
01060 
01061         if (ufep) {
01062             if (s->umvplus) {
01063                 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
01064                     skip_bits1(&s->gb);
01065             }
01066             if(s->h263_slice_structured){
01067                 if (get_bits1(&s->gb) != 0) {
01068                     av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
01069                 }
01070                 if (get_bits1(&s->gb) != 0) {
01071                     av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
01072                 }
01073             }
01074         }
01075 
01076         s->qscale = get_bits(&s->gb, 5);
01077     }
01078 
01079     s->mb_width = (s->width  + 15) / 16;
01080     s->mb_height = (s->height  + 15) / 16;
01081     s->mb_num = s->mb_width * s->mb_height;
01082 
01083     if (s->pb_frame) {
01084         skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
01085         if (s->custom_pcf)
01086             skip_bits(&s->gb, 2); //extended Temporal reference
01087         skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
01088     }
01089 
01090     /* PEI */
01091     while (get_bits1(&s->gb) != 0) {
01092         skip_bits(&s->gb, 8);
01093     }
01094 
01095     if(s->h263_slice_structured){
01096         if (get_bits1(&s->gb) != 1) {
01097             av_log(s->avctx, AV_LOG_ERROR, "SEPB1 marker missing\n");
01098             return -1;
01099         }
01100 
01101         ff_h263_decode_mba(s);
01102 
01103         if (get_bits1(&s->gb) != 1) {
01104             av_log(s->avctx, AV_LOG_ERROR, "SEPB2 marker missing\n");
01105             return -1;
01106         }
01107     }
01108     s->f_code = 1;
01109 
01110     if(s->h263_aic){
01111          s->y_dc_scale_table=
01112          s->c_dc_scale_table= ff_aic_dc_scale_table;
01113     }else{
01114         s->y_dc_scale_table=
01115         s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
01116     }
01117 
01118         ff_h263_show_pict_info(s);
01119     if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO")){
01120         int i,j;
01121         for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
01122         av_log(s->avctx, AV_LOG_DEBUG, "\n");
01123         for(i=0; i<13; i++){
01124             for(j=0; j<3; j++){
01125                 int v= get_bits(&s->gb, 8);
01126                 v |= get_sbits(&s->gb, 8)<<8;
01127                 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
01128             }
01129             av_log(s->avctx, AV_LOG_DEBUG, "\n");
01130         }
01131         for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
01132     }
01133 
01134     return 0;
01135 }