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/internal.h"
35 #include "libavutil/mathematics.h"
37 #include "mpegvideo.h"
42 #include "mpeg4video.h"
44 // The defines below define the number of bits that are read at once for
45 // reading vlc values. Changing these may improve speed and data cache needs
46 // be aware though that decreasing them may need the number of stages that is
47 // passed to get_vlc* to be increased.
49 #define H263_MBTYPE_B_VLC_BITS 6
50 #define CBPC_B_VLC_BITS 3
52 static const int h263_mb_type_b_map[15]= {
53 MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
54 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
55 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
56 MB_TYPE_L0 | MB_TYPE_16x16,
57 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_16x16,
58 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
59 MB_TYPE_L1 | MB_TYPE_16x16,
60 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_16x16,
61 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
62 MB_TYPE_L0L1 | MB_TYPE_16x16,
63 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_16x16,
64 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
66 MB_TYPE_INTRA4x4 | MB_TYPE_CBP,
67 MB_TYPE_INTRA4x4 | MB_TYPE_CBP | MB_TYPE_QUANT,
70 void ff_h263_show_pict_info(MpegEncContext *s){
71 if(s->avctx->debug&FF_DEBUG_PICT_INFO){
72 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",
73 s->qscale, av_get_picture_type_char(s->pict_type),
74 s->gb.size_in_bits, 1-s->no_rounding,
76 s->umvplus ? " UMV" : "",
77 s->h263_long_vectors ? " LONG" : "",
78 s->h263_plus ? " +" : "",
79 s->h263_aic ? " AIC" : "",
80 s->alt_inter_vlc ? " AIV" : "",
81 s->modified_quant ? " MQ" : "",
82 s->loop_filter ? " LOOP" : "",
83 s->h263_slice_structured ? " SS" : "",
84 s->avctx->time_base.den, s->avctx->time_base.num
89 /***********************************************/
92 VLC ff_h263_intra_MCBPC_vlc;
93 VLC ff_h263_inter_MCBPC_vlc;
96 static VLC h263_mbtype_b_vlc;
97 static VLC cbpc_b_vlc;
101 /* XXX: find a better solution to handle static init */
102 av_cold void ff_h263_decode_init_vlc(void)
104 static volatile int done = 0;
107 INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
108 ff_h263_intra_MCBPC_bits, 1, 1,
109 ff_h263_intra_MCBPC_code, 1, 1, 72);
110 INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
111 ff_h263_inter_MCBPC_bits, 1, 1,
112 ff_h263_inter_MCBPC_code, 1, 1, 198);
113 INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
114 &ff_h263_cbpy_tab[0][1], 2, 1,
115 &ff_h263_cbpy_tab[0][0], 2, 1, 64);
116 INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
117 &ff_mvtab[0][1], 2, 1,
118 &ff_mvtab[0][0], 2, 1, 538);
119 ff_init_rl(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
120 ff_init_rl(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
121 INIT_VLC_RL(ff_h263_rl_inter, 554);
122 INIT_VLC_RL(ff_rl_intra_aic, 554);
123 INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
124 &ff_h263_mbtype_b_tab[0][1], 2, 1,
125 &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
126 INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
127 &ff_cbpc_b_tab[0][1], 2, 1,
128 &ff_cbpc_b_tab[0][0], 2, 1, 8);
133 int ff_h263_decode_mba(MpegEncContext *s)
138 if(s->mb_num-1 <= ff_mba_max[i]) break;
140 mb_pos= get_bits(&s->gb, ff_mba_length[i]);
141 s->mb_x= mb_pos % s->mb_width;
142 s->mb_y= mb_pos / s->mb_width;
148 * Decode the group of blocks header or slice header.
149 * @return <0 if an error occurred
151 static int h263_decode_gob_header(MpegEncContext *s)
153 unsigned int val, gob_number;
156 /* Check for GOB Start Code */
157 val = show_bits(&s->gb, 16);
161 /* We have a GBSC probably with GSTUFF */
162 skip_bits(&s->gb, 16); /* Drop the zeros */
163 left= get_bits_left(&s->gb);
164 //MN: we must check the bits left or we might end in a infinite loop (or segfault)
165 for(;left>13; left--){
166 if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
171 if(s->h263_slice_structured){
172 if(get_bits1(&s->gb)==0)
175 ff_h263_decode_mba(s);
178 if(get_bits1(&s->gb)==0)
181 s->qscale = get_bits(&s->gb, 5); /* SQUANT */
182 if(get_bits1(&s->gb)==0)
184 skip_bits(&s->gb, 2); /* GFID */
186 gob_number = get_bits(&s->gb, 5); /* GN */
188 s->mb_y= s->gob_index* gob_number;
189 skip_bits(&s->gb, 2); /* GFID */
190 s->qscale = get_bits(&s->gb, 5); /* GQUANT */
193 if(s->mb_y >= s->mb_height)
203 * Find the next resync_marker.
204 * @param p pointer to buffer to scan
205 * @param end pointer to the end of the buffer
206 * @return pointer to the next resync_marker, or end if none was found
208 const uint8_t *ff_h263_find_resync_marker(MpegEncContext *s, const uint8_t *av_restrict p, const uint8_t *av_restrict end)
214 if(s->resync_marker){
215 int prefix_len = ff_mpeg4_get_video_packet_prefix_length(s);
218 if (!p[-1] && ((p[1] >> (23-prefix_len)) == 1)) return p - 1;
219 else if (!p[ 1] && ((p[2] >> (23-prefix_len)) == 1)) return p;
227 * Decode the group of blocks / video packet header.
228 * @return bit position of the resync_marker, or <0 if none was found
230 int ff_h263_resync(MpegEncContext *s){
233 if(s->codec_id==AV_CODEC_ID_MPEG4){
235 align_get_bits(&s->gb);
238 if(show_bits(&s->gb, 16)==0){
239 pos= get_bits_count(&s->gb);
240 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
241 ret= ff_mpeg4_decode_video_packet_header(s);
243 ret= h263_decode_gob_header(s);
247 //OK, it's not where it is supposed to be ...
248 s->gb= s->last_resync_gb;
249 align_get_bits(&s->gb);
250 left= get_bits_left(&s->gb);
252 for(;left>16+1+5+5; left-=8){
253 if(show_bits(&s->gb, 16)==0){
254 GetBitContext bak= s->gb;
256 pos= get_bits_count(&s->gb);
257 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
258 ret= ff_mpeg4_decode_video_packet_header(s);
260 ret= h263_decode_gob_header(s);
266 skip_bits(&s->gb, 8);
272 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
274 int code, val, sign, shift;
275 code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
282 sign = get_bits1(&s->gb);
286 val = (val - 1) << shift;
287 val |= get_bits(&s->gb, shift);
294 /* modulo decoding */
295 if (!s->h263_long_vectors) {
296 val = sign_extend(val, 5 + f_code);
298 /* horrible h263 long vector mode */
299 if (pred < -31 && val < -63)
301 if (pred > 32 && val > 63)
309 /* Decode RVLC of H.263+ UMV */
310 static int h263p_decode_umotion(MpegEncContext * s, int pred)
314 if (get_bits1(&s->gb)) /* Motion difference = 0 */
317 code = 2 + get_bits1(&s->gb);
319 while (get_bits1(&s->gb))
322 code += get_bits1(&s->gb);
327 code = (sign) ? (pred - code) : (pred + code);
328 av_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
334 * read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
336 static void preview_obmc(MpegEncContext *s){
337 GetBitContext gb= s->gb;
339 int cbpc, i, pred_x, pred_y, mx, my;
341 const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
342 const int stride= s->b8_stride*2;
345 s->block_index[i]+= 2;
347 s->block_index[i]+= 1;
350 av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
353 if (get_bits1(&s->gb)) {
355 mot_val = s->current_picture.motion_val[0][s->block_index[0]];
356 mot_val[0 ]= mot_val[2 ]=
357 mot_val[0+stride]= mot_val[2+stride]= 0;
358 mot_val[1 ]= mot_val[3 ]=
359 mot_val[1+stride]= mot_val[3+stride]= 0;
361 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
364 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
368 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
370 get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
372 if(s->modified_quant){
373 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
374 else skip_bits(&s->gb, 5);
376 skip_bits(&s->gb, 2);
379 if ((cbpc & 16) == 0) {
380 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
381 /* 16x16 motion prediction */
382 mot_val= ff_h263_pred_motion(s, 0, 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);
393 mot_val[0 ]= mot_val[2 ]=
394 mot_val[0+stride]= mot_val[2+stride]= mx;
395 mot_val[1 ]= mot_val[3 ]=
396 mot_val[1+stride]= mot_val[3+stride]= my;
398 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
400 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
402 mx = h263p_decode_umotion(s, pred_x);
404 mx = ff_h263_decode_motion(s, pred_x, 1);
407 my = h263p_decode_umotion(s, pred_y);
409 my = ff_h263_decode_motion(s, pred_y, 1);
410 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
411 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
420 s->block_index[i]-= 2;
422 s->block_index[i]-= 1;
428 static void h263_decode_dquant(MpegEncContext *s){
429 static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
431 if(s->modified_quant){
432 if(get_bits1(&s->gb))
433 s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
435 s->qscale= get_bits(&s->gb, 5);
437 s->qscale += quant_tab[get_bits(&s->gb, 2)];
438 ff_set_qscale(s, s->qscale);
441 static int h263_decode_block(MpegEncContext * s, int16_t * block,
444 int code, level, i, j, last, run;
445 RLTable *rl = &ff_h263_rl_inter;
446 const uint8_t *scan_table;
447 GetBitContext gb= s->gb;
449 scan_table = s->intra_scantable.permutated;
450 if (s->h263_aic && s->mb_intra) {
451 rl = &ff_rl_intra_aic;
455 scan_table = s->intra_v_scantable.permutated; /* left */
457 scan_table = s->intra_h_scantable.permutated; /* top */
459 } else if (s->mb_intra) {
461 if(s->codec_id == AV_CODEC_ID_RV10){
462 #if CONFIG_RV10_DECODER
463 if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
465 component = (n <= 3 ? 0 : n - 4 + 1);
466 level = s->last_dc[component];
467 if (s->rv10_first_dc_coded[component]) {
468 diff = ff_rv_decode_dc(s, n);
472 level = level & 0xff; /* handle wrap round */
473 s->last_dc[component] = level;
475 s->rv10_first_dc_coded[component] = 1;
478 level = get_bits(&s->gb, 8);
484 level = get_bits(&s->gb, 8);
485 if((level&0x7F) == 0){
486 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
487 if(s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
499 if (s->mb_intra && s->h263_aic)
501 s->block_last_index[n] = i - 1;
506 code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
508 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
513 if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
514 ff_flv2_decode_ac_esc(&s->gb, &level, &run, &last);
516 last = get_bits1(&s->gb);
517 run = get_bits(&s->gb, 6);
518 level = (int8_t)get_bits(&s->gb, 8);
520 if (s->codec_id == AV_CODEC_ID_RV10) {
521 /* XXX: should patch encoder too */
522 level = get_sbits(&s->gb, 12);
524 level = get_bits(&s->gb, 5);
525 level |= get_sbits(&s->gb, 6)<<5;
530 run = rl->table_run[code];
531 level = rl->table_level[code];
532 last = code >= rl->last;
533 if (get_bits1(&s->gb))
538 if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
539 //Looks like a hack but no, it's the way it is supposed to work ...
540 rl = &ff_rl_intra_aic;
543 s->dsp.clear_block(block);
546 av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
556 if (s->mb_intra && s->h263_aic) {
557 ff_h263_pred_acdc(s, block, n);
560 s->block_last_index[n] = i;
564 static int h263_skip_b_part(MpegEncContext *s, int cbp)
566 LOCAL_ALIGNED_16(int16_t, dblock, [64]);
570 /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
571 * but real value should be restored in order to be used later (in OBMC condition)
574 memcpy(bli, s->block_last_index, sizeof(bli));
576 for (i = 0; i < 6; i++) {
577 if (h263_decode_block(s, dblock, i, cbp&32) < 0)
582 memcpy(s->block_last_index, bli, sizeof(bli));
586 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
590 if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
592 if (pb_frame == 2 && c)
594 } else { // h.263 Annex M improved PB-frame
595 mv = get_unary(gb, 0, 4) + 1;
600 *cbpb = get_bits(gb, 6);
604 int ff_h263_decode_mb(MpegEncContext *s,
605 int16_t block[6][64])
607 int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
609 const int xy= s->mb_x + s->mb_y * s->mb_stride;
610 int cbpb = 0, pb_mv_count = 0;
612 av_assert2(!s->h263_pred);
614 if (s->pict_type == AV_PICTURE_TYPE_P) {
616 if (get_bits1(&s->gb)) {
620 s->block_last_index[i] = -1;
621 s->mv_dir = MV_DIR_FORWARD;
622 s->mv_type = MV_TYPE_16X16;
623 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
626 s->mb_skipped = !(s->obmc | s->loop_filter);
629 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
631 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
636 s->dsp.clear_blocks(s->block[0]);
639 s->mb_intra = ((cbpc & 4) != 0);
640 if (s->mb_intra) goto intra;
642 if(s->pb_frame && get_bits1(&s->gb))
643 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
644 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
646 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
649 cbp = (cbpc & 3) | (cbpy << 2);
651 h263_decode_dquant(s);
654 s->mv_dir = MV_DIR_FORWARD;
655 if ((cbpc & 16) == 0) {
656 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
657 /* 16x16 motion prediction */
658 s->mv_type = MV_TYPE_16X16;
659 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
661 mx = h263p_decode_umotion(s, pred_x);
663 mx = ff_h263_decode_motion(s, pred_x, 1);
669 my = h263p_decode_umotion(s, pred_y);
671 my = ff_h263_decode_motion(s, pred_y, 1);
678 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
679 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
681 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
682 s->mv_type = MV_TYPE_8X8;
684 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
686 mx = h263p_decode_umotion(s, pred_x);
688 mx = ff_h263_decode_motion(s, pred_x, 1);
693 my = h263p_decode_umotion(s, pred_y);
695 my = ff_h263_decode_motion(s, pred_y, 1);
700 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
701 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
706 } else if(s->pict_type==AV_PICTURE_TYPE_B) {
708 const int stride= s->b8_stride;
709 int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
710 int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
711 // const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
714 mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
715 mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
716 mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
717 mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
720 mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
722 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
726 mb_type= h263_mb_type_b_map[ mb_type ];
729 s->mb_intra = IS_INTRA(mb_type);
730 if(HAS_CBP(mb_type)){
731 s->dsp.clear_blocks(s->block[0]);
732 cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
734 dquant = IS_QUANT(mb_type);
738 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
741 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
745 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
748 cbp = (cbpc & 3) | (cbpy << 2);
752 av_assert2(!s->mb_intra);
754 if(IS_QUANT(mb_type)){
755 h263_decode_dquant(s);
758 if(IS_DIRECT(mb_type)){
759 s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
760 mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
763 s->mv_type= MV_TYPE_16X16;
766 if(USES_LIST(mb_type, 0)){
767 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
768 s->mv_dir = MV_DIR_FORWARD;
770 mx = ff_h263_decode_motion(s, mx, 1);
771 my = ff_h263_decode_motion(s, my, 1);
775 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
776 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
779 if(USES_LIST(mb_type, 1)){
780 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
781 s->mv_dir |= MV_DIR_BACKWARD;
783 mx = ff_h263_decode_motion(s, mx, 1);
784 my = ff_h263_decode_motion(s, my, 1);
788 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
789 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
793 s->current_picture.mb_type[xy] = mb_type;
794 } else { /* I-Frame */
796 cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
798 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
803 s->dsp.clear_blocks(s->block[0]);
808 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
810 s->ac_pred = get_bits1(&s->gb);
812 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
814 s->h263_aic_dir = get_bits1(&s->gb);
819 if(s->pb_frame && get_bits1(&s->gb))
820 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
821 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
823 av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
826 cbp = (cbpc & 3) | (cbpy << 2);
828 h263_decode_dquant(s);
831 pb_mv_count += !!s->pb_frame;
834 while(pb_mv_count--){
835 ff_h263_decode_motion(s, 0, 1);
836 ff_h263_decode_motion(s, 0, 1);
839 /* decode each block */
840 for (i = 0; i < 6; i++) {
841 if (h263_decode_block(s, block[i], i, cbp&32) < 0)
846 if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
848 if(s->obmc && !s->mb_intra){
849 if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
854 /* per-MB end of slice check */
856 int v= show_bits(&s->gb, 16);
858 if (get_bits_left(&s->gb) < 16) {
859 v >>= 16 - get_bits_left(&s->gb);
869 /* most is hardcoded. should extend to handle all h263 streams */
870 int ff_h263_decode_picture_header(MpegEncContext *s)
872 int format, width, height, i;
875 align_get_bits(&s->gb);
877 if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
878 av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
881 startcode= get_bits(&s->gb, 22-8);
883 for(i= get_bits_left(&s->gb); i>24; i-=8) {
884 startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
886 if(startcode == 0x20)
890 if (startcode != 0x20) {
891 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
894 /* temporal reference */
895 i = get_bits(&s->gb, 8); /* picture timestamp */
896 if( (s->picture_number&~0xFF)+i < s->picture_number)
898 s->current_picture_ptr->f.pts =
899 s->picture_number= (s->picture_number&~0xFF) + i;
901 /* PTYPE starts here */
902 if (get_bits1(&s->gb) != 1) {
904 av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
907 if (get_bits1(&s->gb) != 0) {
908 av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
909 return -1; /* h263 id */
911 skip_bits1(&s->gb); /* split screen off */
912 skip_bits1(&s->gb); /* camera off */
913 skip_bits1(&s->gb); /* freeze picture release off */
915 format = get_bits(&s->gb, 3);
920 7 extended PTYPE (PLUSPTYPE)
923 if (format != 7 && format != 6) {
926 width = ff_h263_format[format][0];
927 height = ff_h263_format[format][1];
931 s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
933 s->h263_long_vectors = get_bits1(&s->gb);
935 if (get_bits1(&s->gb) != 0) {
936 av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
937 return -1; /* SAC: off */
939 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
940 s->unrestricted_mv = s->h263_long_vectors || s->obmc;
942 s->pb_frame = get_bits1(&s->gb);
943 s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
944 skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
948 s->avctx->sample_aspect_ratio= (AVRational){12,11};
949 s->avctx->time_base= (AVRational){1001, 30000};
955 ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
957 /* ufep other than 0 and 1 are reserved */
960 format = get_bits(&s->gb, 3);
961 av_dlog(s->avctx, "ufep=1, format: %d\n", format);
962 s->custom_pcf= get_bits1(&s->gb);
963 s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
964 if (get_bits1(&s->gb) != 0) {
965 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
967 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
968 s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
969 s->loop_filter= get_bits1(&s->gb);
970 s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
974 s->h263_slice_structured= get_bits1(&s->gb);
975 if (get_bits1(&s->gb) != 0) {
976 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
978 if (get_bits1(&s->gb) != 0) {
979 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
981 s->alt_inter_vlc= get_bits1(&s->gb);
982 s->modified_quant= get_bits1(&s->gb);
983 if(s->modified_quant)
984 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
986 skip_bits(&s->gb, 1); /* Prevent start code emulation */
988 skip_bits(&s->gb, 3); /* Reserved */
989 } else if (ufep != 0) {
990 av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
995 s->pict_type = get_bits(&s->gb, 3);
996 switch(s->pict_type){
997 case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
998 case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
999 case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
1000 case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
1001 case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
1005 skip_bits(&s->gb, 2);
1006 s->no_rounding = get_bits1(&s->gb);
1007 skip_bits(&s->gb, 4);
1009 /* Get the picture dimensions */
1012 /* Custom Picture Format (CPFMT) */
1013 s->aspect_ratio_info = get_bits(&s->gb, 4);
1014 av_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1019 3 - 10:11 (525-type 4:3)
1020 4 - 16:11 (CIF 16:9)
1021 5 - 40:33 (525-type 16:9)
1024 width = (get_bits(&s->gb, 9) + 1) * 4;
1026 height = get_bits(&s->gb, 9) * 4;
1027 av_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1028 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1029 /* aspected dimensions */
1030 s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1031 s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1033 s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1036 width = ff_h263_format[format][0];
1037 height = ff_h263_format[format][1];
1038 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1040 s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
1041 if ((width == 0) || (height == 0))
1048 s->avctx->time_base.den= 1800000;
1049 s->avctx->time_base.num= 1000 + get_bits1(&s->gb);
1050 s->avctx->time_base.num*= get_bits(&s->gb, 7);
1051 if(s->avctx->time_base.num == 0){
1052 av_log(s, AV_LOG_ERROR, "zero framerate\n");
1055 gcd= av_gcd(s->avctx->time_base.den, s->avctx->time_base.num);
1056 s->avctx->time_base.den /= gcd;
1057 s->avctx->time_base.num /= gcd;
1059 s->avctx->time_base= (AVRational){1001, 30000};
1064 skip_bits(&s->gb, 2); //extended Temporal reference
1069 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1072 if(s->h263_slice_structured){
1073 if (get_bits1(&s->gb) != 0) {
1074 av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1076 if (get_bits1(&s->gb) != 0) {
1077 av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1082 s->qscale = get_bits(&s->gb, 5);
1085 if (s->width == 0 || s->height == 0) {
1086 av_log(s->avctx, AV_LOG_ERROR, "dimensions 0\n");
1089 s->mb_width = (s->width + 15) / 16;
1090 s->mb_height = (s->height + 15) / 16;
1091 s->mb_num = s->mb_width * s->mb_height;
1094 skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1096 skip_bits(&s->gb, 2); //extended Temporal reference
1097 skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1100 if (s->pict_type!=AV_PICTURE_TYPE_B) {
1101 s->time = s->picture_number;
1102 s->pp_time = s->time - s->last_non_b_time;
1103 s->last_non_b_time = s->time;
1105 s->time = s->picture_number;
1106 s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1107 if (s->pp_time <=s->pb_time ||
1108 s->pp_time <= s->pp_time - s->pb_time ||
1113 ff_mpeg4_init_direct_mv(s);
1117 while (get_bits1(&s->gb) != 0) {
1118 skip_bits(&s->gb, 8);
1121 if(s->h263_slice_structured){
1122 if (get_bits1(&s->gb) != 1) {
1123 av_log(s->avctx, AV_LOG_ERROR, "SEPB1 marker missing\n");
1127 ff_h263_decode_mba(s);
1129 if (get_bits1(&s->gb) != 1) {
1130 av_log(s->avctx, AV_LOG_ERROR, "SEPB2 marker missing\n");
1137 s->y_dc_scale_table=
1138 s->c_dc_scale_table= ff_aic_dc_scale_table;
1140 s->y_dc_scale_table=
1141 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1144 ff_h263_show_pict_info(s);
1145 if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1147 for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1148 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1149 for(i=0; i<13; i++){
1151 int v= get_bits(&s->gb, 8);
1152 v |= get_sbits(&s->gb, 8)<<8;
1153 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1155 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1157 for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));