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FFmpeg/libavcodec/ituh263dec.c
Andreas Rheinhardt daf8b10eeb avcodec/rv10: Use symbol table more effectively 
The RealVideo 1.0 decoder uses VLCs to parse DC coefficients. But the
values returned from get_vlc2() are not directly used; instead
-(val - 128) (which is in the range -127..128) is. This transformation
is unnecessary as it can effectively be done when initializing the VLC
by modifying the symbols table used. There is just one minor
complication: The chroma table is incomplete and in order to distinguish
an error from get_vlc2() (due to an invalid code) the ordinary return
range is modified to 0..255. This is possible because the only caller of
this function is (on success) only interested in the return value modulo
256.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2020-12-08 17:51:45 +01:00

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/*
* ITU H.263 bitstream decoder
* Copyright (c) 2000,2001 Fabrice Bellard
* H.263+ 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
* H.263 decoder.
*/
#define UNCHECKED_BITSTREAM_READER 1
#include <limits.h>
#include "libavutil/attributes.h"
#include "libavutil/imgutils.h"
#include "libavutil/internal.h"
#include "libavutil/mathematics.h"
#include "avcodec.h"
#include "mpegvideo.h"
#include "h263.h"
#include "h263data.h"
#include "internal.h"
#include "mathops.h"
#include "mpegutils.h"
#include "unary.h"
#include "flv.h"
#include "rv10.h"
#include "mpeg4video.h"
#include "mpegvideodata.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->framerate.num, s->avctx->framerate.den
);
}
}
/***********************************************/
/* 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 */
av_cold void ff_h263_decode_init_vlc(void)
{
static volatile int done = 0;
if (!done) {
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_rl_init(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
ff_rl_init(&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);
done = 1;
}
}
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);
left = FFMIN(left, 32);
//MN: we must check the bits left or we might end in an 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(check_marker(s->avctx, &s->gb, "before MBA")==0)
return -1;
ff_h263_decode_mba(s);
if(s->mb_num > 1583)
if(check_marker(s->avctx, &s->gb, "after MBA")==0)
return -1;
s->qscale = get_bits(&s->gb, 5); /* SQUANT */
if(check_marker(s->avctx, &s->gb, "after SQUANT")==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;
}
/**
* Decode the group of blocks / video packet header / slice header (MPEG-4 Studio).
* @return bit position of the resync_marker, or <0 if none was found
*/
int ff_h263_resync(MpegEncContext *s){
int left, pos, ret;
/* In MPEG-4 studio mode look for a new slice startcode
* and decode slice header */
if(s->codec_id==AV_CODEC_ID_MPEG4 && s->studio_profile) {
align_get_bits(&s->gb);
while (get_bits_left(&s->gb) >= 32 && show_bits_long(&s->gb, 32) != SLICE_START_CODE) {
get_bits(&s->gb, 8);
}
if (get_bits_left(&s->gb) >= 32 && show_bits_long(&s->gb, 32) == SLICE_START_CODE)
return get_bits_count(&s->gb);
else
return -1;
}
if(s->codec_id==AV_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==AV_CODEC_ID_MPEG4)
ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
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==AV_CODEC_ID_MPEG4)
ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
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 H.263 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);
if (code >= 32768) {
avpriv_request_sample(s->avctx, "Huge DMV");
return 0xffff;
}
}
sign = code & 1;
code >>= 1;
code = (sign) ? (pred - code) : (pred + code);
ff_tlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
return code;
}
/**
* read the next MVs for OBMC. yes this is an 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++;
av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
do{
if (get_bits1(&s->gb)) {
/* skip mb */
mot_val = s->current_picture.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.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.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.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.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, int16_t * block,
int n, int coded)
{
int level, i, j, 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 (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
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 < 0)
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;
}
}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->avctx->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:
{
OPEN_READER(re, &s->gb);
i--; // offset by -1 to allow direct indexing of scan_table
for(;;) {
UPDATE_CACHE(re, &s->gb);
GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
if (run == 66) {
if (level){
CLOSE_READER(re, &s->gb);
av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
return -1;
}
/* escape */
if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
int is11 = SHOW_UBITS(re, &s->gb, 1);
SKIP_CACHE(re, &s->gb, 1);
run = SHOW_UBITS(re, &s->gb, 7) + 1;
if (is11) {
SKIP_COUNTER(re, &s->gb, 1 + 7);
UPDATE_CACHE(re, &s->gb);
level = SHOW_SBITS(re, &s->gb, 11);
SKIP_COUNTER(re, &s->gb, 11);
} else {
SKIP_CACHE(re, &s->gb, 7);
level = SHOW_SBITS(re, &s->gb, 7);
SKIP_COUNTER(re, &s->gb, 1 + 7 + 7);
}
} else {
run = SHOW_UBITS(re, &s->gb, 7) + 1;
SKIP_CACHE(re, &s->gb, 7);
level = (int8_t)SHOW_UBITS(re, &s->gb, 8);
SKIP_COUNTER(re, &s->gb, 7 + 8);
if(level == -128){
UPDATE_CACHE(re, &s->gb);
if (s->codec_id == AV_CODEC_ID_RV10) {
/* XXX: should patch encoder too */
level = SHOW_SBITS(re, &s->gb, 12);
SKIP_COUNTER(re, &s->gb, 12);
}else{
level = SHOW_UBITS(re, &s->gb, 5);
SKIP_CACHE(re, &s->gb, 5);
level |= SHOW_SBITS(re, &s->gb, 6) * (1<<5);
SKIP_COUNTER(re, &s->gb, 5 + 6);
}
}
}
} else {
if (SHOW_UBITS(re, &s->gb, 1))
level = -level;
SKIP_COUNTER(re, &s->gb, 1);
}
i += run;
if (i >= 64){
CLOSE_READER(re, &s->gb);
// redo update without last flag, revert -1 offset
i = i - run + ((run-1)&63) + 1;
if (i < 64) {
// only last marker, no overrun
block[scan_table[i]] = level;
break;
}
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->bdsp.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;
}
}
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_32(int16_t, dblock, [64]);
int i, mbi;
int bli[6];
/* 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;
memcpy(bli, s->block_last_index, sizeof(bli));
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;
memcpy(s->block_last_index, bli, sizeof(bli));
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;
}
#define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
#define tab_bias (tab_size / 2)
static inline void set_one_direct_mv(MpegEncContext *s, Picture *p, int i)
{
int xy = s->block_index[i];
uint16_t time_pp = s->pp_time;
uint16_t time_pb = s->pb_time;
int p_mx, p_my;
p_mx = p->motion_val[0][xy][0];
if ((unsigned)(p_mx + tab_bias) < tab_size) {
s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias];
s->mv[1][i][0] = s->direct_scale_mv[1][p_mx + tab_bias];
} else {
s->mv[0][i][0] = p_mx * time_pb / time_pp;
s->mv[1][i][0] = p_mx * (time_pb - time_pp) / time_pp;
}
p_my = p->motion_val[0][xy][1];
if ((unsigned)(p_my + tab_bias) < tab_size) {
s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias];
s->mv[1][i][1] = s->direct_scale_mv[1][p_my + tab_bias];
} else {
s->mv[0][i][1] = p_my * time_pb / time_pp;
s->mv[1][i][1] = p_my * (time_pb - time_pp) / time_pp;
}
}
/**
* @return the mb_type
*/
static int set_direct_mv(MpegEncContext *s)
{
const int mb_index = s->mb_x + s->mb_y * s->mb_stride;
Picture *p = &s->next_picture;
int colocated_mb_type = p->mb_type[mb_index];
int i;
if (s->codec_tag == AV_RL32("U263") && p->f->pict_type == AV_PICTURE_TYPE_I) {
p = &s->last_picture;
colocated_mb_type = p->mb_type[mb_index];
}
if (IS_8X8(colocated_mb_type)) {
s->mv_type = MV_TYPE_8X8;
for (i = 0; i < 4; i++)
set_one_direct_mv(s, p, i);
return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
} else {
set_one_direct_mv(s, p, 0);
s->mv[0][1][0] =
s->mv[0][2][0] =
s->mv[0][3][0] = s->mv[0][0][0];
s->mv[0][1][1] =
s->mv[0][2][1] =
s->mv[0][3][1] = s->mv[0][0][1];
s->mv[1][1][0] =
s->mv[1][2][0] =
s->mv[1][3][0] = s->mv[1][0][0];
s->mv[1][1][1] =
s->mv[1][2][1] =
s->mv[1][3][1] = s->mv[1][0][1];
s->mv_type = MV_TYPE_8X8;
// Note see prev line
return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1;
}
}
int ff_h263_decode_mb(MpegEncContext *s,
int16_t 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;
av_assert2(!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.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 SLICE_ERROR;
}
}while(cbpc == 20);
s->bdsp.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 (cbpy < 0) {
av_log(s->avctx, AV_LOG_ERROR, "cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
return SLICE_ERROR;
}
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.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 SLICE_ERROR;
if (s->umvplus)
my = h263p_decode_umotion(s, pred_y);
else
my = ff_h263_decode_motion(s, pred_y, 1);
if (my >= 0xffff)
return SLICE_ERROR;
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.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 SLICE_ERROR;
if (s->umvplus)
my = h263p_decode_umotion(s, pred_y);
else
my = ff_h263_decode_motion(s, pred_y, 1);
if (my >= 0xffff)
return SLICE_ERROR;
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.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
int16_t *mot_val1 = s->current_picture.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 SLICE_ERROR;
}
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->bdsp.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 SLICE_ERROR;
}
if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
cbpy ^= 0xF;
cbp = (cbpc & 3) | (cbpy << 2);
}else
cbp=0;
av_assert2(!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 |= set_direct_mv(s);
}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, &pred_x, &pred_y);
s->mv_dir = MV_DIR_FORWARD;
if (s->umvplus)
mx = h263p_decode_umotion(s, pred_x);
else
mx = ff_h263_decode_motion(s, pred_x, 1);
if (mx >= 0xffff)
return SLICE_ERROR;
if (s->umvplus)
my = h263p_decode_umotion(s, pred_y);
else
my = ff_h263_decode_motion(s, pred_y, 1);
if (my >= 0xffff)
return SLICE_ERROR;
if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
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, &pred_x, &pred_y);
s->mv_dir |= MV_DIR_BACKWARD;
if (s->umvplus)
mx = h263p_decode_umotion(s, pred_x);
else
mx = ff_h263_decode_motion(s, pred_x, 1);
if (mx >= 0xffff)
return SLICE_ERROR;
if (s->umvplus)
my = h263p_decode_umotion(s, pred_y);
else
my = ff_h263_decode_motion(s, pred_y, 1);
if (my >= 0xffff)
return SLICE_ERROR;
if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
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.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 SLICE_ERROR;
}
}while(cbpc == 8);
s->bdsp.clear_blocks(s->block[0]);
dquant = cbpc & 4;
s->mb_intra = 1;
intra:
s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
if (s->h263_aic) {
s->ac_pred = get_bits1(&s->gb);
if(s->ac_pred){
s->current_picture.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 SLICE_ERROR;
}
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:
if (get_bits_left(&s->gb) < 0)
return AVERROR_INVALIDDATA;
/* 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 H.263 streams. */
int ff_h263_decode_picture_header(MpegEncContext *s)
{
int format, width, height, i, ret;
uint32_t startcode;
align_get_bits(&s->gb);
if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
}
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 */
i -= (i - (s->picture_number & 0xFF) + 128) & ~0xFF;
s->picture_number= (s->picture_number&~0xFF) + i;
/* PTYPE starts here */
if (check_marker(s->avctx, &s->gb, "in PTYPE") != 1) {
return -1;
}
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
return -1; /* H.263 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, "H.263 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->framerate = (AVRational){ 30000, 1001 };
} 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);
ff_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;
if(s->avctx->lowres)
s->loop_filter = 0;
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);
/* Get the picture dimensions */
if (ufep) {
if (format == 6) {
/* Custom Picture Format (CPFMT) */
s->aspect_ratio_info = get_bits(&s->gb, 4);
ff_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
/* aspect ratios:
0 - forbidden
1 - 1:1
2 - 12:11 (CIF 4:3)
3 - 10:11 (525-type 4:3)
4 - 16:11 (CIF 16:9)
5 - 40:33 (525-type 16:9)
6-14 - reserved
*/
width = (get_bits(&s->gb, 9) + 1) * 4;
check_marker(s->avctx, &s->gb, "in dimensions");
height = get_bits(&s->gb, 9) * 4;
ff_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
/* expected dimensions */
s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
}else{
s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
}
} else {
width = ff_h263_format[format][0];
height = ff_h263_format[format][1];
s->avctx->sample_aspect_ratio= (AVRational){12,11};
}
s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
if ((width == 0) || (height == 0))
return -1;
s->width = width;
s->height = height;
if(s->custom_pcf){
int gcd;
s->avctx->framerate.num = 1800000;
s->avctx->framerate.den = 1000 + get_bits1(&s->gb);
s->avctx->framerate.den *= get_bits(&s->gb, 7);
if(s->avctx->framerate.den == 0){
av_log(s, AV_LOG_ERROR, "zero framerate\n");
return -1;
}
gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
s->avctx->framerate.den /= gcd;
s->avctx->framerate.num /= gcd;
}else{
s->avctx->framerate = (AVRational){ 30000, 1001 };
}
}
if(s->custom_pcf){
skip_bits(&s->gb, 2); //extended Temporal reference
}
if (ufep) {
if (s->umvplus) {
if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
skip_bits1(&s->gb);
}
if(s->h263_slice_structured){
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
}
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
}
}
if (s->pict_type == AV_PICTURE_TYPE_B) {
skip_bits(&s->gb, 4); //ELNUM
if (ufep == 1) {
skip_bits(&s->gb, 4); // RLNUM
}
}
}
s->qscale = get_bits(&s->gb, 5);
}
if ((ret = av_image_check_size(s->width, s->height, 0, s)) < 0)
return ret;
if (!(s->avctx->flags2 & AV_CODEC_FLAG2_CHUNKS)) {
if ((s->width * s->height / 256 / 8) > get_bits_left(&s->gb))
return AVERROR_INVALIDDATA;
}
s->mb_width = (s->width + 15) / 16;
s->mb_height = (s->height + 15) / 16;
s->mb_num = s->mb_width * s->mb_height;
if (s->pb_frame) {
skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
if (s->custom_pcf)
skip_bits(&s->gb, 2); //extended Temporal reference
skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
}
if (s->pict_type!=AV_PICTURE_TYPE_B) {
s->time = s->picture_number;
s->pp_time = s->time - s->last_non_b_time;
s->last_non_b_time = s->time;
}else{
s->time = s->picture_number;
s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
if (s->pp_time <=s->pb_time ||
s->pp_time <= s->pp_time - s->pb_time ||
s->pp_time <= 0){
s->pp_time = 2;
s->pb_time = 1;
}
ff_mpeg4_init_direct_mv(s);
}
/* PEI */
if (skip_1stop_8data_bits(&s->gb) < 0)
return AVERROR_INVALIDDATA;
if(s->h263_slice_structured){
if (check_marker(s->avctx, &s->gb, "SEPB1") != 1) {
return -1;
}
ff_h263_decode_mba(s);
if (check_marker(s->avctx, &s->gb, "SEPB2") != 1) {
return -1;
}
}
s->f_code = 1;
if (s->pict_type == AV_PICTURE_TYPE_B)
s->low_delay = 0;
if(s->h263_aic){
s->y_dc_scale_table=
s->c_dc_scale_table= ff_aic_dc_scale_table;
}else{
s->y_dc_scale_table=
s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
}
ff_h263_show_pict_info(s);
if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
int i,j;
for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
av_log(s->avctx, AV_LOG_DEBUG, "\n");
for(i=0; i<13; i++){
for(j=0; j<3; j++){
int v= get_bits(&s->gb, 8);
v |= get_sbits(&s->gb, 8) * (1 << 8);
av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
}
av_log(s->avctx, AV_LOG_DEBUG, "\n");
}
for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
}
return 0;
}
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