2 * ITU H263 bitstream decoder
3 * Copyright (c) 2000,2001 Fabrice Bellard
5 * Copyright (c) 2001 Juan J. Sierralta P
6 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
8 * This file is part of FFmpeg.
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30 #define UNCHECKED_BITSTREAM_READER 1
33 #include "libavutil/attributes.h"
34 #include "libavutil/imgutils.h"
35 #include "libavutil/internal.h"
36 #include "libavutil/mathematics.h"
38 #include "mpegvideo.h"
43 #include "mpegutils.h"
47 #include "mpeg4video.h"
48 #include "mpegvideodata.h"
50 // The defines below define the number of bits that are read at once for
51 // reading vlc values. Changing these may improve speed and data cache needs
52 // be aware though that decreasing them may need the number of stages that is
53 // passed to get_vlc* to be increased.
55 #define H263_MBTYPE_B_VLC_BITS 6
56 #define CBPC_B_VLC_BITS 3
58 static const int h263_mb_type_b_map[15]= {
59 MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
60 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
61 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
62 MB_TYPE_L0 | MB_TYPE_16x16,
63 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_16x16,
64 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
65 MB_TYPE_L1 | MB_TYPE_16x16,
66 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_16x16,
67 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
68 MB_TYPE_L0L1 | MB_TYPE_16x16,
69 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_16x16,
70 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
72 MB_TYPE_INTRA4x4 | MB_TYPE_CBP,
73 MB_TYPE_INTRA4x4 | MB_TYPE_CBP | MB_TYPE_QUANT,
76 void ff_h263_show_pict_info(MpegEncContext *s){
77 if(s->avctx->debug&FF_DEBUG_PICT_INFO){
78 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",
79 s->qscale, av_get_picture_type_char(s->pict_type),
80 s->gb.size_in_bits, 1-s->no_rounding,
82 s->umvplus ? " UMV" : "",
83 s->h263_long_vectors ? " LONG" : "",
84 s->h263_plus ? " +" : "",
85 s->h263_aic ? " AIC" : "",
86 s->alt_inter_vlc ? " AIV" : "",
87 s->modified_quant ? " MQ" : "",
88 s->loop_filter ? " LOOP" : "",
89 s->h263_slice_structured ? " SS" : "",
90 s->avctx->framerate.num, s->avctx->framerate.den
95 /***********************************************/
98 VLC ff_h263_intra_MCBPC_vlc;
99 VLC ff_h263_inter_MCBPC_vlc;
100 VLC ff_h263_cbpy_vlc;
102 static VLC h263_mbtype_b_vlc;
103 static VLC cbpc_b_vlc;
107 /* XXX: find a better solution to handle static init */
108 av_cold void ff_h263_decode_init_vlc(void)
110 static volatile int done = 0;
113 INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
114 ff_h263_intra_MCBPC_bits, 1, 1,
115 ff_h263_intra_MCBPC_code, 1, 1, 72);
116 INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
117 ff_h263_inter_MCBPC_bits, 1, 1,
118 ff_h263_inter_MCBPC_code, 1, 1, 198);
119 INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
120 &ff_h263_cbpy_tab[0][1], 2, 1,
121 &ff_h263_cbpy_tab[0][0], 2, 1, 64);
122 INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
123 &ff_mvtab[0][1], 2, 1,
124 &ff_mvtab[0][0], 2, 1, 538);
125 ff_rl_init(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
126 ff_rl_init(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
127 INIT_VLC_RL(ff_h263_rl_inter, 554);
128 INIT_VLC_RL(ff_rl_intra_aic, 554);
129 INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
130 &ff_h263_mbtype_b_tab[0][1], 2, 1,
131 &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
132 INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
133 &ff_cbpc_b_tab[0][1], 2, 1,
134 &ff_cbpc_b_tab[0][0], 2, 1, 8);
139 int ff_h263_decode_mba(MpegEncContext *s)
143 for (i = 0; i < 6; i++)
144 if (s->mb_num - 1 <= ff_mba_max[i])
146 mb_pos = get_bits(&s->gb, ff_mba_length[i]);
147 s->mb_x = mb_pos % s->mb_width;
148 s->mb_y = mb_pos / s->mb_width;
154 * Decode the group of blocks header or slice header.
155 * @return <0 if an error occurred
157 static int h263_decode_gob_header(MpegEncContext *s)
159 unsigned int val, gob_number;
162 /* Check for GOB Start Code */
163 val = show_bits(&s->gb, 16);
167 /* We have a GBSC probably with GSTUFF */
168 skip_bits(&s->gb, 16); /* Drop the zeros */
169 left= get_bits_left(&s->gb);
170 //MN: we must check the bits left or we might end in an infinite loop (or segfault)
171 for(;left>13; left--){
172 if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
177 if(s->h263_slice_structured){
178 if(check_marker(&s->gb, "before MBA")==0)
181 ff_h263_decode_mba(s);
184 if(check_marker(&s->gb, "after MBA")==0)
187 s->qscale = get_bits(&s->gb, 5); /* SQUANT */
188 if(check_marker(&s->gb, "after SQUANT")==0)
190 skip_bits(&s->gb, 2); /* GFID */
192 gob_number = get_bits(&s->gb, 5); /* GN */
194 s->mb_y= s->gob_index* gob_number;
195 skip_bits(&s->gb, 2); /* GFID */
196 s->qscale = get_bits(&s->gb, 5); /* GQUANT */
199 if(s->mb_y >= s->mb_height)
209 * Decode the group of blocks / video packet header.
210 * @return bit position of the resync_marker, or <0 if none was found
212 int ff_h263_resync(MpegEncContext *s){
215 if(s->codec_id==AV_CODEC_ID_MPEG4){
217 align_get_bits(&s->gb);
220 if(show_bits(&s->gb, 16)==0){
221 pos= get_bits_count(&s->gb);
222 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
223 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
225 ret= h263_decode_gob_header(s);
229 //OK, it's not where it is supposed to be ...
230 s->gb= s->last_resync_gb;
231 align_get_bits(&s->gb);
232 left= get_bits_left(&s->gb);
234 for(;left>16+1+5+5; left-=8){
235 if(show_bits(&s->gb, 16)==0){
236 GetBitContext bak= s->gb;
238 pos= get_bits_count(&s->gb);
239 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
240 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
242 ret= h263_decode_gob_header(s);
248 skip_bits(&s->gb, 8);
254 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
256 int code, val, sign, shift;
257 code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
264 sign = get_bits1(&s->gb);
268 val = (val - 1) << shift;
269 val |= get_bits(&s->gb, shift);
276 /* modulo decoding */
277 if (!s->h263_long_vectors) {
278 val = sign_extend(val, 5 + f_code);
280 /* horrible h263 long vector mode */
281 if (pred < -31 && val < -63)
283 if (pred > 32 && val > 63)
291 /* Decode RVLC of H.263+ UMV */
292 static int h263p_decode_umotion(MpegEncContext * s, int pred)
296 if (get_bits1(&s->gb)) /* Motion difference = 0 */
299 code = 2 + get_bits1(&s->gb);
301 while (get_bits1(&s->gb))
304 code += get_bits1(&s->gb);
309 code = (sign) ? (pred - code) : (pred + code);
310 ff_tlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
316 * read the next MVs for OBMC. yes this is an ugly hack, feel free to send a patch :)
318 static void preview_obmc(MpegEncContext *s){
319 GetBitContext gb= s->gb;
321 int cbpc, i, pred_x, pred_y, mx, my;
323 const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
324 const int stride= s->b8_stride*2;
327 s->block_index[i]+= 2;
329 s->block_index[i]+= 1;
332 av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
335 if (get_bits1(&s->gb)) {
337 mot_val = s->current_picture.motion_val[0][s->block_index[0]];
338 mot_val[0 ]= mot_val[2 ]=
339 mot_val[0+stride]= mot_val[2+stride]= 0;
340 mot_val[1 ]= mot_val[3 ]=
341 mot_val[1+stride]= mot_val[3+stride]= 0;
343 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
346 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
350 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
352 get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
354 if(s->modified_quant){
355 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
356 else skip_bits(&s->gb, 5);
358 skip_bits(&s->gb, 2);
361 if ((cbpc & 16) == 0) {
362 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
363 /* 16x16 motion prediction */
364 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
366 mx = h263p_decode_umotion(s, pred_x);
368 mx = ff_h263_decode_motion(s, pred_x, 1);
371 my = h263p_decode_umotion(s, pred_y);
373 my = ff_h263_decode_motion(s, pred_y, 1);
375 mot_val[0 ]= mot_val[2 ]=
376 mot_val[0+stride]= mot_val[2+stride]= mx;
377 mot_val[1 ]= mot_val[3 ]=
378 mot_val[1+stride]= mot_val[3+stride]= my;
380 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
382 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
384 mx = h263p_decode_umotion(s, pred_x);
386 mx = ff_h263_decode_motion(s, pred_x, 1);
389 my = h263p_decode_umotion(s, pred_y);
391 my = ff_h263_decode_motion(s, pred_y, 1);
392 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
393 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
402 s->block_index[i]-= 2;
404 s->block_index[i]-= 1;
410 static void h263_decode_dquant(MpegEncContext *s){
411 static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
413 if(s->modified_quant){
414 if(get_bits1(&s->gb))
415 s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
417 s->qscale= get_bits(&s->gb, 5);
419 s->qscale += quant_tab[get_bits(&s->gb, 2)];
420 ff_set_qscale(s, s->qscale);
423 static int h263_decode_block(MpegEncContext * s, int16_t * block,
426 int level, i, j, run;
427 RLTable *rl = &ff_h263_rl_inter;
428 const uint8_t *scan_table;
429 GetBitContext gb= s->gb;
431 scan_table = s->intra_scantable.permutated;
432 if (s->h263_aic && s->mb_intra) {
433 rl = &ff_rl_intra_aic;
437 scan_table = s->intra_v_scantable.permutated; /* left */
439 scan_table = s->intra_h_scantable.permutated; /* top */
441 } else if (s->mb_intra) {
443 if (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
444 if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
446 component = (n <= 3 ? 0 : n - 4 + 1);
447 level = s->last_dc[component];
448 if (s->rv10_first_dc_coded[component]) {
449 diff = ff_rv_decode_dc(s, n);
453 level = level & 0xff; /* handle wrap round */
454 s->last_dc[component] = level;
456 s->rv10_first_dc_coded[component] = 1;
459 level = get_bits(&s->gb, 8);
464 level = get_bits(&s->gb, 8);
465 if((level&0x7F) == 0){
466 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
467 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
479 if (s->mb_intra && s->h263_aic)
481 s->block_last_index[n] = i - 1;
486 OPEN_READER(re, &s->gb);
487 i--; // offset by -1 to allow direct indexing of scan_table
489 UPDATE_CACHE(re, &s->gb);
490 GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
493 CLOSE_READER(re, &s->gb);
494 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
498 if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
499 int is11 = SHOW_UBITS(re, &s->gb, 1);
500 SKIP_CACHE(re, &s->gb, 1);
501 run = SHOW_UBITS(re, &s->gb, 7) + 1;
503 SKIP_COUNTER(re, &s->gb, 1 + 7);
504 UPDATE_CACHE(re, &s->gb);
505 level = SHOW_SBITS(re, &s->gb, 11);
506 SKIP_COUNTER(re, &s->gb, 11);
508 SKIP_CACHE(re, &s->gb, 7);
509 level = SHOW_SBITS(re, &s->gb, 7);
510 SKIP_COUNTER(re, &s->gb, 1 + 7 + 7);
513 run = SHOW_UBITS(re, &s->gb, 7) + 1;
514 SKIP_CACHE(re, &s->gb, 7);
515 level = (int8_t)SHOW_UBITS(re, &s->gb, 8);
516 SKIP_COUNTER(re, &s->gb, 7 + 8);
518 UPDATE_CACHE(re, &s->gb);
519 if (s->codec_id == AV_CODEC_ID_RV10) {
520 /* XXX: should patch encoder too */
521 level = SHOW_SBITS(re, &s->gb, 12);
522 SKIP_COUNTER(re, &s->gb, 12);
524 level = SHOW_UBITS(re, &s->gb, 5);
525 SKIP_CACHE(re, &s->gb, 5);
526 level |= SHOW_SBITS(re, &s->gb, 6)<<5;
527 SKIP_COUNTER(re, &s->gb, 5 + 6);
532 if (SHOW_UBITS(re, &s->gb, 1))
534 SKIP_COUNTER(re, &s->gb, 1);
538 CLOSE_READER(re, &s->gb);
539 // redo update without last flag, revert -1 offset
540 i = i - run + ((run-1)&63) + 1;
542 // only last marker, no overrun
543 block[scan_table[i]] = level;
546 if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
547 //Looks like a hack but no, it's the way it is supposed to work ...
548 rl = &ff_rl_intra_aic;
551 s->bdsp.clear_block(block);
554 av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
562 if (s->mb_intra && s->h263_aic) {
563 ff_h263_pred_acdc(s, block, n);
566 s->block_last_index[n] = i;
570 static int h263_skip_b_part(MpegEncContext *s, int cbp)
572 LOCAL_ALIGNED_16(int16_t, dblock, [64]);
576 /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
577 * but real value should be restored in order to be used later (in OBMC condition)
580 memcpy(bli, s->block_last_index, sizeof(bli));
582 for (i = 0; i < 6; i++) {
583 if (h263_decode_block(s, dblock, i, cbp&32) < 0)
588 memcpy(s->block_last_index, bli, sizeof(bli));
592 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
596 if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
598 if (pb_frame == 2 && c)
600 } else { // h.263 Annex M improved PB-frame
601 mv = get_unary(gb, 0, 4) + 1;
606 *cbpb = get_bits(gb, 6);
610 int ff_h263_decode_mb(MpegEncContext *s,
611 int16_t block[6][64])
613 int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
615 const int xy= s->mb_x + s->mb_y * s->mb_stride;
616 int cbpb = 0, pb_mv_count = 0;
618 av_assert2(!s->h263_pred);
620 if (s->pict_type == AV_PICTURE_TYPE_P) {
622 if (get_bits1(&s->gb)) {
626 s->block_last_index[i] = -1;
627 s->mv_dir = MV_DIR_FORWARD;
628 s->mv_type = MV_TYPE_16X16;
629 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
632 s->mb_skipped = !(s->obmc | s->loop_filter);
635 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
637 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
642 s->bdsp.clear_blocks(s->block[0]);
645 s->mb_intra = ((cbpc & 4) != 0);
646 if (s->mb_intra) goto intra;
648 if(s->pb_frame && get_bits1(&s->gb))
649 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
650 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
652 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
655 cbp = (cbpc & 3) | (cbpy << 2);
657 h263_decode_dquant(s);
660 s->mv_dir = MV_DIR_FORWARD;
661 if ((cbpc & 16) == 0) {
662 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
663 /* 16x16 motion prediction */
664 s->mv_type = MV_TYPE_16X16;
665 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
667 mx = h263p_decode_umotion(s, pred_x);
669 mx = ff_h263_decode_motion(s, pred_x, 1);
675 my = h263p_decode_umotion(s, pred_y);
677 my = ff_h263_decode_motion(s, pred_y, 1);
684 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
685 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
687 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
688 s->mv_type = MV_TYPE_8X8;
690 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
692 mx = h263p_decode_umotion(s, pred_x);
694 mx = ff_h263_decode_motion(s, pred_x, 1);
699 my = h263p_decode_umotion(s, pred_y);
701 my = ff_h263_decode_motion(s, pred_y, 1);
706 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
707 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
712 } else if(s->pict_type==AV_PICTURE_TYPE_B) {
714 const int stride= s->b8_stride;
715 int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
716 int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
717 // const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
720 mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
721 mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
722 mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
723 mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
726 mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
728 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
732 mb_type= h263_mb_type_b_map[ mb_type ];
735 s->mb_intra = IS_INTRA(mb_type);
736 if(HAS_CBP(mb_type)){
737 s->bdsp.clear_blocks(s->block[0]);
738 cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
740 dquant = IS_QUANT(mb_type);
744 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
747 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
751 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
754 cbp = (cbpc & 3) | (cbpy << 2);
758 av_assert2(!s->mb_intra);
760 if(IS_QUANT(mb_type)){
761 h263_decode_dquant(s);
764 if(IS_DIRECT(mb_type)){
765 s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
766 mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
769 s->mv_type= MV_TYPE_16X16;
772 if(USES_LIST(mb_type, 0)){
773 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
774 s->mv_dir = MV_DIR_FORWARD;
776 mx = ff_h263_decode_motion(s, mx, 1);
777 my = ff_h263_decode_motion(s, my, 1);
781 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
782 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
785 if(USES_LIST(mb_type, 1)){
786 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
787 s->mv_dir |= MV_DIR_BACKWARD;
789 mx = ff_h263_decode_motion(s, mx, 1);
790 my = ff_h263_decode_motion(s, my, 1);
794 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
795 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
799 s->current_picture.mb_type[xy] = mb_type;
800 } else { /* I-Frame */
802 cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
804 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
809 s->bdsp.clear_blocks(s->block[0]);
814 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
816 s->ac_pred = get_bits1(&s->gb);
818 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
820 s->h263_aic_dir = get_bits1(&s->gb);
825 if(s->pb_frame && get_bits1(&s->gb))
826 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
827 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
829 av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
832 cbp = (cbpc & 3) | (cbpy << 2);
834 h263_decode_dquant(s);
837 pb_mv_count += !!s->pb_frame;
840 while(pb_mv_count--){
841 ff_h263_decode_motion(s, 0, 1);
842 ff_h263_decode_motion(s, 0, 1);
845 /* decode each block */
846 for (i = 0; i < 6; i++) {
847 if (h263_decode_block(s, block[i], i, cbp&32) < 0)
852 if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
854 if(s->obmc && !s->mb_intra){
855 if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
860 /* per-MB end of slice check */
862 int v= show_bits(&s->gb, 16);
864 if (get_bits_left(&s->gb) < 16) {
865 v >>= 16 - get_bits_left(&s->gb);
875 /* most is hardcoded. should extend to handle all h263 streams */
876 int ff_h263_decode_picture_header(MpegEncContext *s)
878 int format, width, height, i, ret;
881 align_get_bits(&s->gb);
883 if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
884 av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
887 startcode= get_bits(&s->gb, 22-8);
889 for(i= get_bits_left(&s->gb); i>24; i-=8) {
890 startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
892 if(startcode == 0x20)
896 if (startcode != 0x20) {
897 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
900 /* temporal reference */
901 i = get_bits(&s->gb, 8); /* picture timestamp */
902 if( (s->picture_number&~0xFF)+i < s->picture_number)
904 s->picture_number= (s->picture_number&~0xFF) + i;
906 /* PTYPE starts here */
907 if (check_marker(&s->gb, "in PTYPE") != 1) {
910 if (get_bits1(&s->gb) != 0) {
911 av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
912 return -1; /* h263 id */
914 skip_bits1(&s->gb); /* split screen off */
915 skip_bits1(&s->gb); /* camera off */
916 skip_bits1(&s->gb); /* freeze picture release off */
918 format = get_bits(&s->gb, 3);
923 7 extended PTYPE (PLUSPTYPE)
926 if (format != 7 && format != 6) {
929 width = ff_h263_format[format][0];
930 height = ff_h263_format[format][1];
934 s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
936 s->h263_long_vectors = get_bits1(&s->gb);
938 if (get_bits1(&s->gb) != 0) {
939 av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
940 return -1; /* SAC: off */
942 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
943 s->unrestricted_mv = s->h263_long_vectors || s->obmc;
945 s->pb_frame = get_bits1(&s->gb);
946 s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
947 skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
951 s->avctx->sample_aspect_ratio= (AVRational){12,11};
952 s->avctx->framerate = (AVRational){ 30000, 1001 };
958 ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
960 /* ufep other than 0 and 1 are reserved */
963 format = get_bits(&s->gb, 3);
964 ff_dlog(s->avctx, "ufep=1, format: %d\n", format);
965 s->custom_pcf= get_bits1(&s->gb);
966 s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
967 if (get_bits1(&s->gb) != 0) {
968 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
970 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
971 s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
972 s->loop_filter= get_bits1(&s->gb);
973 s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
977 s->h263_slice_structured= get_bits1(&s->gb);
978 if (get_bits1(&s->gb) != 0) {
979 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
981 if (get_bits1(&s->gb) != 0) {
982 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
984 s->alt_inter_vlc= get_bits1(&s->gb);
985 s->modified_quant= get_bits1(&s->gb);
986 if(s->modified_quant)
987 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
989 skip_bits(&s->gb, 1); /* Prevent start code emulation */
991 skip_bits(&s->gb, 3); /* Reserved */
992 } else if (ufep != 0) {
993 av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
998 s->pict_type = get_bits(&s->gb, 3);
999 switch(s->pict_type){
1000 case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
1001 case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
1002 case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
1003 case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
1004 case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
1008 skip_bits(&s->gb, 2);
1009 s->no_rounding = get_bits1(&s->gb);
1010 skip_bits(&s->gb, 4);
1012 /* Get the picture dimensions */
1015 /* Custom Picture Format (CPFMT) */
1016 s->aspect_ratio_info = get_bits(&s->gb, 4);
1017 ff_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1022 3 - 10:11 (525-type 4:3)
1023 4 - 16:11 (CIF 16:9)
1024 5 - 40:33 (525-type 16:9)
1027 width = (get_bits(&s->gb, 9) + 1) * 4;
1028 check_marker(&s->gb, "in dimensions");
1029 height = get_bits(&s->gb, 9) * 4;
1030 ff_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1031 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1032 /* aspected dimensions */
1033 s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1034 s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1036 s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1039 width = ff_h263_format[format][0];
1040 height = ff_h263_format[format][1];
1041 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1043 s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
1044 if ((width == 0) || (height == 0))
1051 s->avctx->framerate.num = 1800000;
1052 s->avctx->framerate.den = 1000 + get_bits1(&s->gb);
1053 s->avctx->framerate.den *= get_bits(&s->gb, 7);
1054 if(s->avctx->framerate.den == 0){
1055 av_log(s, AV_LOG_ERROR, "zero framerate\n");
1058 gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
1059 s->avctx->framerate.den /= gcd;
1060 s->avctx->framerate.num /= gcd;
1062 s->avctx->framerate = (AVRational){ 30000, 1001 };
1067 skip_bits(&s->gb, 2); //extended Temporal reference
1072 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1075 if(s->h263_slice_structured){
1076 if (get_bits1(&s->gb) != 0) {
1077 av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1079 if (get_bits1(&s->gb) != 0) {
1080 av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1085 s->qscale = get_bits(&s->gb, 5);
1088 if ((ret = av_image_check_size(s->width, s->height, 0, s)) < 0)
1091 s->mb_width = (s->width + 15) / 16;
1092 s->mb_height = (s->height + 15) / 16;
1093 s->mb_num = s->mb_width * s->mb_height;
1096 skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1098 skip_bits(&s->gb, 2); //extended Temporal reference
1099 skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1102 if (s->pict_type!=AV_PICTURE_TYPE_B) {
1103 s->time = s->picture_number;
1104 s->pp_time = s->time - s->last_non_b_time;
1105 s->last_non_b_time = s->time;
1107 s->time = s->picture_number;
1108 s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1109 if (s->pp_time <=s->pb_time ||
1110 s->pp_time <= s->pp_time - s->pb_time ||
1115 ff_mpeg4_init_direct_mv(s);
1119 if (skip_1stop_8data_bits(&s->gb) < 0)
1120 return AVERROR_INVALIDDATA;
1122 if(s->h263_slice_structured){
1123 if (check_marker(&s->gb, "SEPB1") != 1) {
1127 ff_h263_decode_mba(s);
1129 if (check_marker(&s->gb, "SEPB2") != 1) {
1136 s->y_dc_scale_table=
1137 s->c_dc_scale_table= ff_aic_dc_scale_table;
1139 s->y_dc_scale_table=
1140 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1143 ff_h263_show_pict_info(s);
1144 if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1146 for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1147 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1148 for(i=0; i<13; i++){
1150 int v= get_bits(&s->gb, 8);
1151 v |= get_sbits(&s->gb, 8)<<8;
1152 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1154 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1156 for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));