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 == 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;
}
}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)<<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;
}
/**
* Decode a macroblock.
* @return <0 if an error occurred
*/
static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
{
MpegEncContext *const s = &h->s;
int level, i, j, run;
RLTable *rl = &ff_h261_rl_tcoeff;
const uint8_t *scan_table;
/* For the variable length encoding there are two code tables, one being
* used for the first transmitted LEVEL in INTER, INTER + MC and
* INTER + MC + FIL blocks, the second for all other LEVELs except the
* first one in INTRA blocks which is fixed length coded with 8 bits.
* NOTE: The two code tables only differ in one VLC so we handle that
* manually. */
scan_table = s->intra_scantable.permutated;
if (s->mb_intra) {
/* DC coef */
level = get_bits(&s->gb, 8);
// 0 (00000000b) and -128 (10000000b) are FORBIDDEN
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);
return -1;
}
/* The code 1000 0000 is not used, the reconstruction level of 1024
* being coded as 1111 1111. */
if (level == 255)
level = 128;
block[0] = level;
i = 1;
} else if (coded) {
// Run Level Code
// EOB Not possible for first level when cbp is available (that's why the table is different)
// 0 1 1s
// * * 0*
int check = show_bits(&s->gb, 2);
i = 0;
if (check & 0x2) {
skip_bits(&s->gb, 2);
block[0] = (check & 0x1) ? -1 : 1;
i = 1;
}
} else {
i = 0;
}
if (!coded) {
s->block_last_index[n] = i - 1;
return 0;
}
{
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], TCOEFF_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 */
/* The remaining combinations of (run, level) are encoded with a
* 20-bit word consisting of 6 bits escape, 6 bits run and 8 bits
* level. */
run = SHOW_UBITS(re, &s->gb, 6) + 1;
SKIP_CACHE(re, &s->gb, 6);
level = SHOW_SBITS(re, &s->gb, 8);
SKIP_COUNTER(re, &s->gb, 6 + 8);
} else if (level == 0) {
break;
} 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);
av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d\n",
s->mb_x, s->mb_y);
return -1;
}
j = scan_table[i];
block[j] = level;
}
CLOSE_READER(re, &s->gb);
}
s->block_last_index[n] = i;
return 0;
}