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 Libav.
10 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
32 #include "libavutil/attributes.h"
33 #include "libavutil/internal.h"
34 #include "libavutil/mathematics.h"
36 #include "mpegvideo.h"
39 #include "mpegutils.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->framerate.num, s->avctx->framerate.den
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)
109 INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
110 ff_h263_intra_MCBPC_bits, 1, 1,
111 ff_h263_intra_MCBPC_code, 1, 1, 72);
112 INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
113 ff_h263_inter_MCBPC_bits, 1, 1,
114 ff_h263_inter_MCBPC_code, 1, 1, 198);
115 INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
116 &ff_h263_cbpy_tab[0][1], 2, 1,
117 &ff_h263_cbpy_tab[0][0], 2, 1, 64);
118 INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
119 &ff_mvtab[0][1], 2, 1,
120 &ff_mvtab[0][0], 2, 1, 538);
121 ff_init_rl(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
122 ff_init_rl(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
123 INIT_VLC_RL(ff_h263_rl_inter, 554);
124 INIT_VLC_RL(ff_rl_intra_aic, 554);
125 INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
126 &ff_h263_mbtype_b_tab[0][1], 2, 1,
127 &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
128 INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
129 &ff_cbpc_b_tab[0][1], 2, 1,
130 &ff_cbpc_b_tab[0][0], 2, 1, 8);
134 int ff_h263_decode_mba(MpegEncContext *s)
139 if(s->mb_num-1 <= ff_mba_max[i]) break;
141 mb_pos= get_bits(&s->gb, ff_mba_length[i]);
142 s->mb_x= mb_pos % s->mb_width;
143 s->mb_y= mb_pos / s->mb_width;
149 * Decode the group of blocks header or slice header.
150 * @return <0 if an error occurred
152 static int h263_decode_gob_header(MpegEncContext *s)
154 unsigned int val, gob_number;
157 /* Check for GOB Start Code */
158 val = show_bits(&s->gb, 16);
162 /* We have a GBSC probably with GSTUFF */
163 skip_bits(&s->gb, 16); /* Drop the zeros */
164 left= get_bits_left(&s->gb);
165 //MN: we must check the bits left or we might end in a infinite loop (or segfault)
166 for(;left>13; left--){
167 if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
172 if(s->h263_slice_structured){
173 if(get_bits1(&s->gb)==0)
176 ff_h263_decode_mba(s);
179 if(get_bits1(&s->gb)==0)
182 s->qscale = get_bits(&s->gb, 5); /* SQUANT */
183 if(get_bits1(&s->gb)==0)
185 skip_bits(&s->gb, 2); /* GFID */
187 gob_number = get_bits(&s->gb, 5); /* GN */
189 s->mb_y= s->gob_index* gob_number;
190 skip_bits(&s->gb, 2); /* GFID */
191 s->qscale = get_bits(&s->gb, 5); /* GQUANT */
194 if(s->mb_y >= s->mb_height)
204 * Find the next resync_marker.
205 * @param p pointer to buffer to scan
206 * @param end pointer to the end of the buffer
207 * @return pointer to the next resync_marker, or end if none was found
209 const uint8_t *ff_h263_find_resync_marker(const uint8_t *restrict p, const uint8_t * restrict end)
217 if (!p[-1] && p[1]) return p - 1;
218 else if(!p[ 1] && p[2]) return p;
225 * Decode the group of blocks / video packet header.
226 * @return bit position of the resync_marker, or <0 if none was found
228 int ff_h263_resync(MpegEncContext *s){
231 if(s->codec_id==AV_CODEC_ID_MPEG4){
233 align_get_bits(&s->gb);
236 if(show_bits(&s->gb, 16)==0){
237 pos= get_bits_count(&s->gb);
238 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
239 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
241 ret= h263_decode_gob_header(s);
245 //OK, it's not where it is supposed to be ...
246 s->gb= s->last_resync_gb;
247 align_get_bits(&s->gb);
248 left= get_bits_left(&s->gb);
250 for(;left>16+1+5+5; left-=8){
251 if(show_bits(&s->gb, 16)==0){
252 GetBitContext bak= s->gb;
254 pos= get_bits_count(&s->gb);
255 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
256 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
258 ret= h263_decode_gob_header(s);
264 skip_bits(&s->gb, 8);
270 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
272 int code, val, sign, shift;
273 code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
280 sign = get_bits1(&s->gb);
284 val = (val - 1) << shift;
285 val |= get_bits(&s->gb, shift);
292 /* modulo decoding */
293 if (!s->h263_long_vectors) {
294 val = sign_extend(val, 5 + f_code);
296 /* horrible h263 long vector mode */
297 if (pred < -31 && val < -63)
299 if (pred > 32 && val > 63)
307 /* Decode RVLC of H.263+ UMV */
308 static int h263p_decode_umotion(MpegEncContext * s, int pred)
312 if (get_bits1(&s->gb)) /* Motion difference = 0 */
315 code = 2 + get_bits1(&s->gb);
317 while (get_bits1(&s->gb))
320 code += get_bits1(&s->gb);
325 code = (sign) ? (pred - code) : (pred + code);
326 av_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
332 * read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
334 static void preview_obmc(MpegEncContext *s){
335 GetBitContext gb= s->gb;
337 int cbpc, i, pred_x, pred_y, mx, my;
339 const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
340 const int stride= s->b8_stride*2;
343 s->block_index[i]+= 2;
345 s->block_index[i]+= 1;
348 assert(s->pict_type == AV_PICTURE_TYPE_P);
351 if (get_bits1(&s->gb)) {
353 mot_val = s->current_picture.motion_val[0][s->block_index[0]];
354 mot_val[0 ]= mot_val[2 ]=
355 mot_val[0+stride]= mot_val[2+stride]= 0;
356 mot_val[1 ]= mot_val[3 ]=
357 mot_val[1+stride]= mot_val[3+stride]= 0;
359 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
362 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
366 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
368 get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
370 if(s->modified_quant){
371 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
372 else skip_bits(&s->gb, 5);
374 skip_bits(&s->gb, 2);
377 if ((cbpc & 16) == 0) {
378 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
379 /* 16x16 motion prediction */
380 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
382 mx = h263p_decode_umotion(s, pred_x);
384 mx = ff_h263_decode_motion(s, pred_x, 1);
387 my = h263p_decode_umotion(s, pred_y);
389 my = ff_h263_decode_motion(s, pred_y, 1);
391 mot_val[0 ]= mot_val[2 ]=
392 mot_val[0+stride]= mot_val[2+stride]= mx;
393 mot_val[1 ]= mot_val[3 ]=
394 mot_val[1+stride]= mot_val[3+stride]= my;
396 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
398 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
400 mx = h263p_decode_umotion(s, pred_x);
402 mx = ff_h263_decode_motion(s, pred_x, 1);
405 my = h263p_decode_umotion(s, pred_y);
407 my = ff_h263_decode_motion(s, pred_y, 1);
408 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
409 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
418 s->block_index[i]-= 2;
420 s->block_index[i]-= 1;
426 static void h263_decode_dquant(MpegEncContext *s){
427 static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
429 if(s->modified_quant){
430 if(get_bits1(&s->gb))
431 s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
433 s->qscale= get_bits(&s->gb, 5);
435 s->qscale += quant_tab[get_bits(&s->gb, 2)];
436 ff_set_qscale(s, s->qscale);
439 static int h263_decode_block(MpegEncContext * s, int16_t * block,
442 int code, level, i, j, last, run;
443 RLTable *rl = &ff_h263_rl_inter;
444 const uint8_t *scan_table;
445 GetBitContext gb= s->gb;
447 scan_table = s->intra_scantable.permutated;
448 if (s->h263_aic && s->mb_intra) {
449 rl = &ff_rl_intra_aic;
453 scan_table = s->intra_v_scantable.permutated; /* left */
455 scan_table = s->intra_h_scantable.permutated; /* top */
457 } else if (s->mb_intra) {
459 if (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
460 if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
462 component = (n <= 3 ? 0 : n - 4 + 1);
463 level = s->last_dc[component];
464 if (s->rv10_first_dc_coded[component]) {
465 diff = ff_rv_decode_dc(s, n);
469 level = level & 0xff; /* handle wrap round */
470 s->last_dc[component] = level;
472 s->rv10_first_dc_coded[component] = 1;
475 level = get_bits(&s->gb, 8);
480 level = get_bits(&s->gb, 8);
481 if((level&0x7F) == 0){
482 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
483 if(s->err_recognition & AV_EF_BITSTREAM)
495 if (s->mb_intra && s->h263_aic)
497 s->block_last_index[n] = i - 1;
502 code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
504 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
509 if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
510 ff_flv2_decode_ac_esc(&s->gb, &level, &run, &last);
512 last = get_bits1(&s->gb);
513 run = get_bits(&s->gb, 6);
514 level = (int8_t)get_bits(&s->gb, 8);
516 if (s->codec_id == AV_CODEC_ID_RV10) {
517 /* XXX: should patch encoder too */
518 level = get_sbits(&s->gb, 12);
520 level = get_bits(&s->gb, 5);
521 level |= get_sbits(&s->gb, 6)<<5;
526 run = rl->table_run[code];
527 level = rl->table_level[code];
528 last = code >= rl->last;
529 if (get_bits1(&s->gb))
534 if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
535 //Looks like a hack but no, it's the way it is supposed to work ...
536 rl = &ff_rl_intra_aic;
539 s->bdsp.clear_block(block);
542 av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
552 if (s->mb_intra && s->h263_aic) {
553 ff_h263_pred_acdc(s, block, n);
556 s->block_last_index[n] = i;
560 static int h263_skip_b_part(MpegEncContext *s, int cbp)
562 LOCAL_ALIGNED_16(int16_t, dblock, [64]);
565 /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
566 * but real value should be restored in order to be used later (in OBMC condition)
570 for (i = 0; i < 6; i++) {
571 if (h263_decode_block(s, dblock, i, cbp&32) < 0)
579 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
583 if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
585 if (pb_frame == 2 && c)
587 } else { // h.263 Annex M improved PB-frame
588 mv = get_unary(gb, 0, 4) + 1;
593 *cbpb = get_bits(gb, 6);
597 int ff_h263_decode_mb(MpegEncContext *s,
598 int16_t block[6][64])
600 int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
602 const int xy= s->mb_x + s->mb_y * s->mb_stride;
603 int cbpb = 0, pb_mv_count = 0;
605 assert(!s->h263_pred);
607 if (s->pict_type == AV_PICTURE_TYPE_P) {
609 if (get_bits1(&s->gb)) {
613 s->block_last_index[i] = -1;
614 s->mv_dir = MV_DIR_FORWARD;
615 s->mv_type = MV_TYPE_16X16;
616 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
619 s->mb_skipped = !(s->obmc | s->loop_filter);
622 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
624 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
629 s->bdsp.clear_blocks(s->block[0]);
632 s->mb_intra = ((cbpc & 4) != 0);
633 if (s->mb_intra) goto intra;
635 if(s->pb_frame && get_bits1(&s->gb))
636 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
637 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
639 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
642 cbp = (cbpc & 3) | (cbpy << 2);
644 h263_decode_dquant(s);
647 s->mv_dir = MV_DIR_FORWARD;
648 if ((cbpc & 16) == 0) {
649 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
650 /* 16x16 motion prediction */
651 s->mv_type = MV_TYPE_16X16;
652 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
654 mx = h263p_decode_umotion(s, pred_x);
656 mx = ff_h263_decode_motion(s, pred_x, 1);
662 my = h263p_decode_umotion(s, pred_y);
664 my = ff_h263_decode_motion(s, pred_y, 1);
671 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
672 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
674 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
675 s->mv_type = MV_TYPE_8X8;
677 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
679 mx = h263p_decode_umotion(s, pred_x);
681 mx = ff_h263_decode_motion(s, pred_x, 1);
686 my = h263p_decode_umotion(s, pred_y);
688 my = ff_h263_decode_motion(s, pred_y, 1);
693 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
694 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
699 } else if(s->pict_type==AV_PICTURE_TYPE_B) {
701 const int stride= s->b8_stride;
702 int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
703 int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
704 // const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
707 mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
708 mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
709 mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
710 mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
713 mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
715 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
719 mb_type= h263_mb_type_b_map[ mb_type ];
722 s->mb_intra = IS_INTRA(mb_type);
723 if(HAS_CBP(mb_type)){
724 s->bdsp.clear_blocks(s->block[0]);
725 cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
727 dquant = IS_QUANT(mb_type);
731 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
734 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
738 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
741 cbp = (cbpc & 3) | (cbpy << 2);
745 assert(!s->mb_intra);
747 if(IS_QUANT(mb_type)){
748 h263_decode_dquant(s);
751 if(IS_DIRECT(mb_type)){
753 return AVERROR_INVALIDDATA;
754 s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
755 mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
758 s->mv_type= MV_TYPE_16X16;
761 if(USES_LIST(mb_type, 0)){
762 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
763 s->mv_dir = MV_DIR_FORWARD;
765 mx = ff_h263_decode_motion(s, mx, 1);
766 my = ff_h263_decode_motion(s, my, 1);
770 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
771 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
774 if(USES_LIST(mb_type, 1)){
775 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
776 s->mv_dir |= MV_DIR_BACKWARD;
778 mx = ff_h263_decode_motion(s, mx, 1);
779 my = ff_h263_decode_motion(s, my, 1);
783 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
784 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
788 s->current_picture.mb_type[xy] = mb_type;
789 } else { /* I-Frame */
791 cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
793 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
798 s->bdsp.clear_blocks(s->block[0]);
803 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
805 s->ac_pred = get_bits1(&s->gb);
807 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
809 s->h263_aic_dir = get_bits1(&s->gb);
814 if(s->pb_frame && get_bits1(&s->gb))
815 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
816 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
818 av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
821 cbp = (cbpc & 3) | (cbpy << 2);
823 h263_decode_dquant(s);
826 pb_mv_count += !!s->pb_frame;
829 while(pb_mv_count--){
830 ff_h263_decode_motion(s, 0, 1);
831 ff_h263_decode_motion(s, 0, 1);
834 /* decode each block */
835 for (i = 0; i < 6; i++) {
836 if (h263_decode_block(s, block[i], i, cbp&32) < 0)
841 if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
843 if(s->obmc && !s->mb_intra){
844 if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
849 /* per-MB end of slice check */
851 int v= show_bits(&s->gb, 16);
853 if (get_bits_left(&s->gb) < 16) {
854 v >>= 16 - get_bits_left(&s->gb);
864 /* most is hardcoded. should extend to handle all h263 streams */
865 int ff_h263_decode_picture_header(MpegEncContext *s)
867 int format, width, height, i;
870 align_get_bits(&s->gb);
872 startcode= get_bits(&s->gb, 22-8);
874 for(i= get_bits_left(&s->gb); i>24; i-=8) {
875 startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
877 if(startcode == 0x20)
881 if (startcode != 0x20) {
882 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
885 /* temporal reference */
886 i = get_bits(&s->gb, 8); /* picture timestamp */
887 if( (s->picture_number&~0xFF)+i < s->picture_number)
889 s->picture_number= (s->picture_number&~0xFF) + i;
891 /* PTYPE starts here */
892 if (get_bits1(&s->gb) != 1) {
894 av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
897 if (get_bits1(&s->gb) != 0) {
898 av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
899 return -1; /* h263 id */
901 skip_bits1(&s->gb); /* split screen off */
902 skip_bits1(&s->gb); /* camera off */
903 skip_bits1(&s->gb); /* freeze picture release off */
905 format = get_bits(&s->gb, 3);
910 7 extended PTYPE (PLUSPTYPE)
913 if (format != 7 && format != 6) {
916 width = ff_h263_format[format][0];
917 height = ff_h263_format[format][1];
921 s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
923 s->h263_long_vectors = get_bits1(&s->gb);
925 if (get_bits1(&s->gb) != 0) {
926 av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
927 return -1; /* SAC: off */
929 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
930 s->unrestricted_mv = s->h263_long_vectors || s->obmc;
932 s->pb_frame = get_bits1(&s->gb);
933 s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
934 skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
938 s->avctx->sample_aspect_ratio= (AVRational){12,11};
939 s->avctx->framerate = (AVRational){ 30000, 1001 };
945 ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
947 /* ufep other than 0 and 1 are reserved */
950 format = get_bits(&s->gb, 3);
951 av_dlog(s->avctx, "ufep=1, format: %d\n", format);
952 s->custom_pcf= get_bits1(&s->gb);
953 s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
954 if (get_bits1(&s->gb) != 0) {
955 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
957 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
958 s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
959 s->loop_filter= get_bits1(&s->gb);
960 s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
962 s->h263_slice_structured= get_bits1(&s->gb);
963 if (get_bits1(&s->gb) != 0) {
964 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
966 if (get_bits1(&s->gb) != 0) {
967 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
969 s->alt_inter_vlc= get_bits1(&s->gb);
970 s->modified_quant= get_bits1(&s->gb);
971 if(s->modified_quant)
972 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
974 skip_bits(&s->gb, 1); /* Prevent start code emulation */
976 skip_bits(&s->gb, 3); /* Reserved */
977 } else if (ufep != 0) {
978 av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
983 s->pict_type = get_bits(&s->gb, 3);
984 switch(s->pict_type){
985 case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
986 case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
987 case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
988 case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
989 case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
993 skip_bits(&s->gb, 2);
994 s->no_rounding = get_bits1(&s->gb);
995 skip_bits(&s->gb, 4);
997 /* Get the picture dimensions */
1000 /* Custom Picture Format (CPFMT) */
1001 s->aspect_ratio_info = get_bits(&s->gb, 4);
1002 av_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1007 3 - 10:11 (525-type 4:3)
1008 4 - 16:11 (CIF 16:9)
1009 5 - 40:33 (525-type 16:9)
1012 width = (get_bits(&s->gb, 9) + 1) * 4;
1014 height = get_bits(&s->gb, 9) * 4;
1015 av_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1016 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1017 /* aspected dimensions */
1018 s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1019 s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1021 s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1024 width = ff_h263_format[format][0];
1025 height = ff_h263_format[format][1];
1026 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1028 if ((width == 0) || (height == 0))
1035 s->avctx->framerate.num = 1800000;
1036 s->avctx->framerate.den = 1000 + get_bits1(&s->gb);
1037 s->avctx->framerate.den *= get_bits(&s->gb, 7);
1038 if(s->avctx->framerate.den == 0){
1039 av_log(s, AV_LOG_ERROR, "zero framerate\n");
1042 gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
1043 s->avctx->framerate.den /= gcd;
1044 s->avctx->framerate.num /= gcd;
1046 s->avctx->framerate = (AVRational){ 30000, 1001 };
1051 skip_bits(&s->gb, 2); //extended Temporal reference
1056 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1059 if(s->h263_slice_structured){
1060 if (get_bits1(&s->gb) != 0) {
1061 av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1063 if (get_bits1(&s->gb) != 0) {
1064 av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1069 s->qscale = get_bits(&s->gb, 5);
1072 s->mb_width = (s->width + 15) / 16;
1073 s->mb_height = (s->height + 15) / 16;
1074 s->mb_num = s->mb_width * s->mb_height;
1077 skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1079 skip_bits(&s->gb, 2); //extended Temporal reference
1080 skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1083 if (s->pict_type!=AV_PICTURE_TYPE_B) {
1084 s->time = s->picture_number;
1085 s->pp_time = s->time - s->last_non_b_time;
1086 s->last_non_b_time = s->time;
1088 s->time = s->picture_number;
1089 s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1090 if (s->pp_time <=s->pb_time ||
1091 s->pp_time <= s->pp_time - s->pb_time ||
1096 ff_mpeg4_init_direct_mv(s);
1100 while (get_bits1(&s->gb) != 0) {
1101 skip_bits(&s->gb, 8);
1104 if(s->h263_slice_structured){
1105 if (get_bits1(&s->gb) != 1) {
1106 av_log(s->avctx, AV_LOG_ERROR, "SEPB1 marker missing\n");
1110 ff_h263_decode_mba(s);
1112 if (get_bits1(&s->gb) != 1) {
1113 av_log(s->avctx, AV_LOG_ERROR, "SEPB2 marker missing\n");
1120 s->y_dc_scale_table=
1121 s->c_dc_scale_table= ff_aic_dc_scale_table;
1123 s->y_dc_scale_table=
1124 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1127 ff_h263_show_pict_info(s);
1128 if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO")){
1130 for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1131 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1132 for(i=0; i<13; i++){
1134 int v= get_bits(&s->gb, 8);
1135 v |= get_sbits(&s->gb, 8)<<8;
1136 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1138 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1140 for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));