/
ituh263dec.c
1147 lines (999 loc) · 36.4 KB
/
ituh263dec.c
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/*
* ITU H263 bitstream decoder
* Copyright (c) 2000,2001 Fabrice Bellard
* H263+ support.
* Copyright (c) 2001 Juan J. Sierralta P
* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* h263 decoder.
*/
#define UNCHECKED_BITSTREAM_READER 1
//#define DEBUG
#include <limits.h>
#include "libavutil/mathematics.h"
#include "dsputil.h"
#include "avcodec.h"
#include "mpegvideo.h"
#include "h263.h"
#include "mathops.h"
#include "unary.h"
#include "flv.h"
#include "mpeg4video.h"
//#undef NDEBUG
//#include <assert.h>
// The defines below define the number of bits that are read at once for
// reading vlc values. Changing these may improve speed and data cache needs
// be aware though that decreasing them may need the number of stages that is
// passed to get_vlc* to be increased.
#define MV_VLC_BITS 9
#define H263_MBTYPE_B_VLC_BITS 6
#define CBPC_B_VLC_BITS 3
static const int h263_mb_type_b_map[15]= {
MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
MB_TYPE_L0 | MB_TYPE_16x16,
MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_16x16,
MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
MB_TYPE_L1 | MB_TYPE_16x16,
MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_16x16,
MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
MB_TYPE_L0L1 | MB_TYPE_16x16,
MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_16x16,
MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
0, //stuffing
MB_TYPE_INTRA4x4 | MB_TYPE_CBP,
MB_TYPE_INTRA4x4 | MB_TYPE_CBP | MB_TYPE_QUANT,
};
void ff_h263_show_pict_info(MpegEncContext *s){
if(s->avctx->debug&FF_DEBUG_PICT_INFO){
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",
s->qscale, av_get_picture_type_char(s->pict_type),
s->gb.size_in_bits, 1-s->no_rounding,
s->obmc ? " AP" : "",
s->umvplus ? " UMV" : "",
s->h263_long_vectors ? " LONG" : "",
s->h263_plus ? " +" : "",
s->h263_aic ? " AIC" : "",
s->alt_inter_vlc ? " AIV" : "",
s->modified_quant ? " MQ" : "",
s->loop_filter ? " LOOP" : "",
s->h263_slice_structured ? " SS" : "",
s->avctx->time_base.den, s->avctx->time_base.num
);
}
}
/***********************************************/
/* decoding */
VLC ff_h263_intra_MCBPC_vlc;
VLC ff_h263_inter_MCBPC_vlc;
VLC ff_h263_cbpy_vlc;
static VLC mv_vlc;
static VLC h263_mbtype_b_vlc;
static VLC cbpc_b_vlc;
/* init vlcs */
/* XXX: find a better solution to handle static init */
void ff_h263_decode_init_vlc(MpegEncContext *s)
{
static int done = 0;
if (!done) {
done = 1;
INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
ff_h263_intra_MCBPC_bits, 1, 1,
ff_h263_intra_MCBPC_code, 1, 1, 72);
INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
ff_h263_inter_MCBPC_bits, 1, 1,
ff_h263_inter_MCBPC_code, 1, 1, 198);
INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
&ff_h263_cbpy_tab[0][1], 2, 1,
&ff_h263_cbpy_tab[0][0], 2, 1, 64);
INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
&ff_mvtab[0][1], 2, 1,
&ff_mvtab[0][0], 2, 1, 538);
ff_init_rl(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
ff_init_rl(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
INIT_VLC_RL(ff_h263_rl_inter, 554);
INIT_VLC_RL(ff_rl_intra_aic, 554);
INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
&ff_h263_mbtype_b_tab[0][1], 2, 1,
&ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
&ff_cbpc_b_tab[0][1], 2, 1,
&ff_cbpc_b_tab[0][0], 2, 1, 8);
}
}
int ff_h263_decode_mba(MpegEncContext *s)
{
int i, mb_pos;
for(i=0; i<6; i++){
if(s->mb_num-1 <= ff_mba_max[i]) break;
}
mb_pos= get_bits(&s->gb, ff_mba_length[i]);
s->mb_x= mb_pos % s->mb_width;
s->mb_y= mb_pos / s->mb_width;
return mb_pos;
}
/**
* Decode the group of blocks header or slice header.
* @return <0 if an error occurred
*/
static int h263_decode_gob_header(MpegEncContext *s)
{
unsigned int val, gob_number;
int left;
/* Check for GOB Start Code */
val = show_bits(&s->gb, 16);
if(val)
return -1;
/* We have a GBSC probably with GSTUFF */
skip_bits(&s->gb, 16); /* Drop the zeros */
left= get_bits_left(&s->gb);
//MN: we must check the bits left or we might end in a infinite loop (or segfault)
for(;left>13; left--){
if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
}
if(left<=13)
return -1;
if(s->h263_slice_structured){
if(get_bits1(&s->gb)==0)
return -1;
ff_h263_decode_mba(s);
if(s->mb_num > 1583)
if(get_bits1(&s->gb)==0)
return -1;
s->qscale = get_bits(&s->gb, 5); /* SQUANT */
if(get_bits1(&s->gb)==0)
return -1;
skip_bits(&s->gb, 2); /* GFID */
}else{
gob_number = get_bits(&s->gb, 5); /* GN */
s->mb_x= 0;
s->mb_y= s->gob_index* gob_number;
skip_bits(&s->gb, 2); /* GFID */
s->qscale = get_bits(&s->gb, 5); /* GQUANT */
}
if(s->mb_y >= s->mb_height)
return -1;
if(s->qscale==0)
return -1;
return 0;
}
/**
* Find the next resync_marker.
* @param p pointer to buffer to scan
* @param end pointer to the end of the buffer
* @return pointer to the next resync_marker, or end if none was found
*/
const uint8_t *ff_h263_find_resync_marker(const uint8_t *restrict p, const uint8_t * restrict end)
{
assert(p < end);
end-=2;
p++;
for(;p<end; p+=2){
if(!*p){
if (!p[-1] && p[1]) return p - 1;
else if(!p[ 1] && p[2]) return p;
}
}
return end+2;
}
/**
* Decode the group of blocks / video packet header.
* @return bit position of the resync_marker, or <0 if none was found
*/
int ff_h263_resync(MpegEncContext *s){
int left, pos, ret;
if(s->codec_id==CODEC_ID_MPEG4){
skip_bits1(&s->gb);
align_get_bits(&s->gb);
}
if(show_bits(&s->gb, 16)==0){
pos= get_bits_count(&s->gb);
if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4)
ret= ff_mpeg4_decode_video_packet_header(s);
else
ret= h263_decode_gob_header(s);
if(ret>=0)
return pos;
}
//OK, it's not where it is supposed to be ...
s->gb= s->last_resync_gb;
align_get_bits(&s->gb);
left= get_bits_left(&s->gb);
for(;left>16+1+5+5; left-=8){
if(show_bits(&s->gb, 16)==0){
GetBitContext bak= s->gb;
pos= get_bits_count(&s->gb);
if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4)
ret= ff_mpeg4_decode_video_packet_header(s);
else
ret= h263_decode_gob_header(s);
if(ret>=0)
return pos;
s->gb= bak;
}
skip_bits(&s->gb, 8);
}
return -1;
}
int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
{
int code, val, sign, shift;
code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
if (code == 0)
return pred;
if (code < 0)
return 0xffff;
sign = get_bits1(&s->gb);
shift = f_code - 1;
val = code;
if (shift) {
val = (val - 1) << shift;
val |= get_bits(&s->gb, shift);
val++;
}
if (sign)
val = -val;
val += pred;
/* modulo decoding */
if (!s->h263_long_vectors) {
val = sign_extend(val, 5 + f_code);
} else {
/* horrible h263 long vector mode */
if (pred < -31 && val < -63)
val += 64;
if (pred > 32 && val > 63)
val -= 64;
}
return val;
}
/* Decode RVLC of H.263+ UMV */
static int h263p_decode_umotion(MpegEncContext * s, int pred)
{
int code = 0, sign;
if (get_bits1(&s->gb)) /* Motion difference = 0 */
return pred;
code = 2 + get_bits1(&s->gb);
while (get_bits1(&s->gb))
{
code <<= 1;
code += get_bits1(&s->gb);
}
sign = code & 1;
code >>= 1;
code = (sign) ? (pred - code) : (pred + code);
av_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
return code;
}
/**
* read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
*/
static void preview_obmc(MpegEncContext *s){
GetBitContext gb= s->gb;
int cbpc, i, pred_x, pred_y, mx, my;
int16_t *mot_val;
const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
const int stride= s->b8_stride*2;
for(i=0; i<4; i++)
s->block_index[i]+= 2;
for(i=4; i<6; i++)
s->block_index[i]+= 1;
s->mb_x++;
assert(s->pict_type == AV_PICTURE_TYPE_P);
do{
if (get_bits1(&s->gb)) {
/* skip mb */
mot_val = s->current_picture.f.motion_val[0][s->block_index[0]];
mot_val[0 ]= mot_val[2 ]=
mot_val[0+stride]= mot_val[2+stride]= 0;
mot_val[1 ]= mot_val[3 ]=
mot_val[1+stride]= mot_val[3+stride]= 0;
s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
goto end;
}
cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
}while(cbpc == 20);
if(cbpc & 4){
s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
}else{
get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
if (cbpc & 8) {
if(s->modified_quant){
if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
else skip_bits(&s->gb, 5);
}else
skip_bits(&s->gb, 2);
}
if ((cbpc & 16) == 0) {
s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
/* 16x16 motion prediction */
mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
if (s->umvplus)
mx = h263p_decode_umotion(s, pred_x);
else
mx = ff_h263_decode_motion(s, pred_x, 1);
if (s->umvplus)
my = h263p_decode_umotion(s, pred_y);
else
my = ff_h263_decode_motion(s, pred_y, 1);
mot_val[0 ]= mot_val[2 ]=
mot_val[0+stride]= mot_val[2+stride]= mx;
mot_val[1 ]= mot_val[3 ]=
mot_val[1+stride]= mot_val[3+stride]= my;
} else {
s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
for(i=0;i<4;i++) {
mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
if (s->umvplus)
mx = h263p_decode_umotion(s, pred_x);
else
mx = ff_h263_decode_motion(s, pred_x, 1);
if (s->umvplus)
my = h263p_decode_umotion(s, pred_y);
else
my = ff_h263_decode_motion(s, pred_y, 1);
if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
mot_val[0] = mx;
mot_val[1] = my;
}
}
}
end:
for(i=0; i<4; i++)
s->block_index[i]-= 2;
for(i=4; i<6; i++)
s->block_index[i]-= 1;
s->mb_x--;
s->gb= gb;
}
static void h263_decode_dquant(MpegEncContext *s){
static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
if(s->modified_quant){
if(get_bits1(&s->gb))
s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
else
s->qscale= get_bits(&s->gb, 5);
}else
s->qscale += quant_tab[get_bits(&s->gb, 2)];
ff_set_qscale(s, s->qscale);
}
static int h263_decode_block(MpegEncContext * s, DCTELEM * block,
int n, int coded)
{
int code, level, i, j, last, run;
RLTable *rl = &ff_h263_rl_inter;
const uint8_t *scan_table;
GetBitContext gb= s->gb;
scan_table = s->intra_scantable.permutated;
if (s->h263_aic && s->mb_intra) {
rl = &ff_rl_intra_aic;
i = 0;
if (s->ac_pred) {
if (s->h263_aic_dir)
scan_table = s->intra_v_scantable.permutated; /* left */
else
scan_table = s->intra_h_scantable.permutated; /* top */
}
} else if (s->mb_intra) {
/* DC coef */
if(s->codec_id == CODEC_ID_RV10){
#if CONFIG_RV10_DECODER
if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
int component, diff;
component = (n <= 3 ? 0 : n - 4 + 1);
level = s->last_dc[component];
if (s->rv10_first_dc_coded[component]) {
diff = ff_rv_decode_dc(s, n);
if (diff == 0xffff)
return -1;
level += diff;
level = level & 0xff; /* handle wrap round */
s->last_dc[component] = level;
} else {
s->rv10_first_dc_coded[component] = 1;
}
} else {
level = get_bits(&s->gb, 8);
if (level == 255)
level = 128;
}
#endif
}else{
level = get_bits(&s->gb, 8);
if((level&0x7F) == 0){
av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
if(s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
return -1;
}
if (level == 255)
level = 128;
}
block[0] = level;
i = 1;
} else {
i = 0;
}
if (!coded) {
if (s->mb_intra && s->h263_aic)
goto not_coded;
s->block_last_index[n] = i - 1;
return 0;
}
retry:
for(;;) {
code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
if (code < 0){
av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
return -1;
}
if (code == rl->n) {
/* escape */
if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
ff_flv2_decode_ac_esc(&s->gb, &level, &run, &last);
} else {
last = get_bits1(&s->gb);
run = get_bits(&s->gb, 6);
level = (int8_t)get_bits(&s->gb, 8);
if(level == -128){
if (s->codec_id == CODEC_ID_RV10) {
/* XXX: should patch encoder too */
level = get_sbits(&s->gb, 12);
}else{
level = get_bits(&s->gb, 5);
level |= get_sbits(&s->gb, 6)<<5;
}
}
}
} else {
run = rl->table_run[code];
level = rl->table_level[code];
last = code >= rl->last;
if (get_bits1(&s->gb))
level = -level;
}
i += run;
if (i >= 64){
if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
//Looks like a hack but no, it's the way it is supposed to work ...
rl = &ff_rl_intra_aic;
i = 0;
s->gb= gb;
s->dsp.clear_block(block);
goto retry;
}
av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
return -1;
}
j = scan_table[i];
block[j] = level;
if (last)
break;
i++;
}
not_coded:
if (s->mb_intra && s->h263_aic) {
ff_h263_pred_acdc(s, block, n);
i = 63;
}
s->block_last_index[n] = i;
return 0;
}
static int h263_skip_b_part(MpegEncContext *s, int cbp)
{
LOCAL_ALIGNED_16(DCTELEM, dblock, [64]);
int i, mbi;
/* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
* but real value should be restored in order to be used later (in OBMC condition)
*/
mbi = s->mb_intra;
s->mb_intra = 0;
for (i = 0; i < 6; i++) {
if (h263_decode_block(s, dblock, i, cbp&32) < 0)
return -1;
cbp+=cbp;
}
s->mb_intra = mbi;
return 0;
}
static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
{
int c, mv = 1;
if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
c = get_bits1(gb);
if (pb_frame == 2 && c)
mv = !get_bits1(gb);
} else { // h.263 Annex M improved PB-frame
mv = get_unary(gb, 0, 4) + 1;
c = mv & 1;
mv = !!(mv & 2);
}
if(c)
*cbpb = get_bits(gb, 6);
return mv;
}
int ff_h263_decode_mb(MpegEncContext *s,
DCTELEM block[6][64])
{
int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
int16_t *mot_val;
const int xy= s->mb_x + s->mb_y * s->mb_stride;
int cbpb = 0, pb_mv_count = 0;
assert(!s->h263_pred);
if (s->pict_type == AV_PICTURE_TYPE_P) {
do{
if (get_bits1(&s->gb)) {
/* skip mb */
s->mb_intra = 0;
for(i=0;i<6;i++)
s->block_last_index[i] = -1;
s->mv_dir = MV_DIR_FORWARD;
s->mv_type = MV_TYPE_16X16;
s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
s->mv[0][0][0] = 0;
s->mv[0][0][1] = 0;
s->mb_skipped = !(s->obmc | s->loop_filter);
goto end;
}
cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
if (cbpc < 0){
av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
return -1;
}
}while(cbpc == 20);
s->dsp.clear_blocks(s->block[0]);
dquant = cbpc & 8;
s->mb_intra = ((cbpc & 4) != 0);
if (s->mb_intra) goto intra;
if(s->pb_frame && get_bits1(&s->gb))
pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
cbpy ^= 0xF;
cbp = (cbpc & 3) | (cbpy << 2);
if (dquant) {
h263_decode_dquant(s);
}
s->mv_dir = MV_DIR_FORWARD;
if ((cbpc & 16) == 0) {
s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
/* 16x16 motion prediction */
s->mv_type = MV_TYPE_16X16;
ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
if (s->umvplus)
mx = h263p_decode_umotion(s, pred_x);
else
mx = ff_h263_decode_motion(s, pred_x, 1);
if (mx >= 0xffff)
return -1;
if (s->umvplus)
my = h263p_decode_umotion(s, pred_y);
else
my = ff_h263_decode_motion(s, pred_y, 1);
if (my >= 0xffff)
return -1;
s->mv[0][0][0] = mx;
s->mv[0][0][1] = my;
if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
} else {
s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
s->mv_type = MV_TYPE_8X8;
for(i=0;i<4;i++) {
mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
if (s->umvplus)
mx = h263p_decode_umotion(s, pred_x);
else
mx = ff_h263_decode_motion(s, pred_x, 1);
if (mx >= 0xffff)
return -1;
if (s->umvplus)
my = h263p_decode_umotion(s, pred_y);
else
my = ff_h263_decode_motion(s, pred_y, 1);
if (my >= 0xffff)
return -1;
s->mv[0][i][0] = mx;
s->mv[0][i][1] = my;
if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
mot_val[0] = mx;
mot_val[1] = my;
}
}
} else if(s->pict_type==AV_PICTURE_TYPE_B) {
int mb_type;
const int stride= s->b8_stride;
int16_t *mot_val0 = s->current_picture.f.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
int16_t *mot_val1 = s->current_picture.f.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
// const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
//FIXME ugly
mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
do{
mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
if (mb_type < 0){
av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
return -1;
}
mb_type= h263_mb_type_b_map[ mb_type ];
}while(!mb_type);
s->mb_intra = IS_INTRA(mb_type);
if(HAS_CBP(mb_type)){
s->dsp.clear_blocks(s->block[0]);
cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
if(s->mb_intra){
dquant = IS_QUANT(mb_type);
goto intra;
}
cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
if (cbpy < 0){
av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
return -1;
}
if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
cbpy ^= 0xF;
cbp = (cbpc & 3) | (cbpy << 2);
}else
cbp=0;
assert(!s->mb_intra);
if(IS_QUANT(mb_type)){
h263_decode_dquant(s);
}
if(IS_DIRECT(mb_type)){
s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
}else{
s->mv_dir = 0;
s->mv_type= MV_TYPE_16X16;
//FIXME UMV
if(USES_LIST(mb_type, 0)){
int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
s->mv_dir = MV_DIR_FORWARD;
mx = ff_h263_decode_motion(s, mx, 1);
my = ff_h263_decode_motion(s, my, 1);
s->mv[0][0][0] = mx;
s->mv[0][0][1] = my;
mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
}
if(USES_LIST(mb_type, 1)){
int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
s->mv_dir |= MV_DIR_BACKWARD;
mx = ff_h263_decode_motion(s, mx, 1);
my = ff_h263_decode_motion(s, my, 1);
s->mv[1][0][0] = mx;
s->mv[1][0][1] = my;
mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
}
}
s->current_picture.f.mb_type[xy] = mb_type;
} else { /* I-Frame */
do{
cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
if (cbpc < 0){
av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
return -1;
}
}while(cbpc == 8);
s->dsp.clear_blocks(s->block[0]);
dquant = cbpc & 4;
s->mb_intra = 1;
intra:
s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
if (s->h263_aic) {
s->ac_pred = get_bits1(&s->gb);
if(s->ac_pred){
s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
s->h263_aic_dir = get_bits1(&s->gb);
}
}else
s->ac_pred = 0;
if(s->pb_frame && get_bits1(&s->gb))
pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
if(cbpy<0){
av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
return -1;
}
cbp = (cbpc & 3) | (cbpy << 2);
if (dquant) {
h263_decode_dquant(s);
}
pb_mv_count += !!s->pb_frame;
}
while(pb_mv_count--){
ff_h263_decode_motion(s, 0, 1);
ff_h263_decode_motion(s, 0, 1);
}
/* decode each block */
for (i = 0; i < 6; i++) {
if (h263_decode_block(s, block[i], i, cbp&32) < 0)
return -1;
cbp+=cbp;
}
if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
return -1;
if(s->obmc && !s->mb_intra){
if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
preview_obmc(s);
}
end:
/* per-MB end of slice check */
{
int v= show_bits(&s->gb, 16);
if (get_bits_left(&s->gb) < 16) {
v >>= 16 - get_bits_left(&s->gb);
}
if(v==0)
return SLICE_END;
}
return SLICE_OK;
}
/* most is hardcoded. should extend to handle all h263 streams */
int ff_h263_decode_picture_header(MpegEncContext *s)
{
int format, width, height, i;
uint32_t startcode;
align_get_bits(&s->gb);
startcode= get_bits(&s->gb, 22-8);
for(i= get_bits_left(&s->gb); i>24; i-=8) {
startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
if(startcode == 0x20)
break;
}
if (startcode != 0x20) {
av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
return -1;
}
/* temporal reference */
i = get_bits(&s->gb, 8); /* picture timestamp */
if( (s->picture_number&~0xFF)+i < s->picture_number)
i+= 256;
s->current_picture_ptr->f.pts =
s->picture_number= (s->picture_number&~0xFF) + i;
/* PTYPE starts here */
if (get_bits1(&s->gb) != 1) {
/* marker */
av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
return -1;
}
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
return -1; /* h263 id */
}
skip_bits1(&s->gb); /* split screen off */
skip_bits1(&s->gb); /* camera off */
skip_bits1(&s->gb); /* freeze picture release off */
format = get_bits(&s->gb, 3);
/*
0 forbidden
1 sub-QCIF
10 QCIF
7 extended PTYPE (PLUSPTYPE)
*/
if (format != 7 && format != 6) {
s->h263_plus = 0;
/* H.263v1 */
width = ff_h263_format[format][0];
height = ff_h263_format[format][1];
if (!width)
return -1;
s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
s->h263_long_vectors = get_bits1(&s->gb);
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
return -1; /* SAC: off */
}
s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
s->unrestricted_mv = s->h263_long_vectors || s->obmc;
s->pb_frame = get_bits1(&s->gb);
s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
s->width = width;
s->height = height;
s->avctx->sample_aspect_ratio= (AVRational){12,11};
s->avctx->time_base= (AVRational){1001, 30000};
} else {
int ufep;
/* H.263v2 */
s->h263_plus = 1;
ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
/* ufep other than 0 and 1 are reserved */
if (ufep == 1) {
/* OPPTYPE */
format = get_bits(&s->gb, 3);
av_dlog(s->avctx, "ufep=1, format: %d\n", format);
s->custom_pcf= get_bits1(&s->gb);
s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
}
s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
s->loop_filter= get_bits1(&s->gb);
s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
s->h263_slice_structured= get_bits1(&s->gb);
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
}
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
}
s->alt_inter_vlc= get_bits1(&s->gb);
s->modified_quant= get_bits1(&s->gb);
if(s->modified_quant)
s->chroma_qscale_table= ff_h263_chroma_qscale_table;
skip_bits(&s->gb, 1); /* Prevent start code emulation */
skip_bits(&s->gb, 3); /* Reserved */
} else if (ufep != 0) {
av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
return -1;
}
/* MPPTYPE */
s->pict_type = get_bits(&s->gb, 3);
switch(s->pict_type){
case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
default:
return -1;
}
skip_bits(&s->gb, 2);
s->no_rounding = get_bits1(&s->gb);
skip_bits(&s->gb, 4);