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mpeg2_fast_decode_block_intra()

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Originally committed as revision 4146 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2005-04-20 20:31:04 +00:00
parent bfaad39f8c
commit dff0f03546
1 changed files with 80 additions and 3 deletions
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83
libavcodec/mpeg12.c
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@ -72,6 +72,7 @@ static inline int mpeg2_decode_block_intra(MpegEncContext *s,
DCTELEM *block,
int n);
static inline int mpeg2_fast_decode_block_non_intra(MpegEncContext *s, DCTELEM *block, int n);
static inline int mpeg2_fast_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n);
static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred);
static void exchange_uv(MpegEncContext *s);
@ -1173,9 +1174,15 @@ static int mpeg_decode_mb(MpegEncContext *s,
#endif
if (s->codec_id == CODEC_ID_MPEG2VIDEO) {
for(i=0;i<mb_block_count;i++) {
if (mpeg2_decode_block_intra(s, s->pblocks[i], i) < 0)
return -1;
if(s->flags2 & CODEC_FLAG2_FAST){
for(i=0;i<6;i++) {
mpeg2_fast_decode_block_intra(s, s->pblocks[i], i);
}
}else{
for(i=0;i<mb_block_count;i++) {
if (mpeg2_decode_block_intra(s, s->pblocks[i], i) < 0)
return -1;
}
}
} else {
for(i=0;i<6;i++) {
@ -1928,6 +1935,76 @@ static inline int mpeg2_decode_block_intra(MpegEncContext *s,
return 0;
}
static inline int mpeg2_fast_decode_block_intra(MpegEncContext *s,
DCTELEM *block,
int n)
{
int level, dc, diff, j, run;
int component;
RLTable *rl;
uint8_t * scantable= s->intra_scantable.permutated;
const uint16_t *quant_matrix;
const int qscale= s->qscale;
/* DC coef */
if (n < 4){
quant_matrix = s->intra_matrix;
component = 0;
}else{
quant_matrix = s->chroma_intra_matrix;
component = (n&1) + 1;
}
diff = decode_dc(&s->gb, component);
if (diff >= 0xffff)
return -1;
dc = s->last_dc[component];
dc += diff;
s->last_dc[component] = dc;
block[0] = dc << (3 - s->intra_dc_precision);
if (s->intra_vlc_format)
rl = &rl_mpeg2;
else
rl = &rl_mpeg1;
{
OPEN_READER(re, &s->gb);
/* now quantify & encode AC coefs */
for(;;) {
UPDATE_CACHE(re, &s->gb);
GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
if(level == 127){
break;
} else if(level != 0) {
scantable += run;
j = *scantable;
level= (level*qscale*quant_matrix[j])>>4;
level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
LAST_SKIP_BITS(re, &s->gb, 1);
} else {
/* escape */
run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
UPDATE_CACHE(re, &s->gb);
level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12);
scantable += run;
j = *scantable;
if(level<0){
level= (-level*qscale*quant_matrix[j])>>4;
level= -level;
}else{
level= (level*qscale*quant_matrix[j])>>4;
}
}
block[j] = level;
}
CLOSE_READER(re, &s->gb);
}
s->block_last_index[n] = scantable - s->intra_scantable.permutated;
return 0;
}
typedef struct Mpeg1Context {
MpegEncContext mpeg_enc_ctx;
int mpeg_enc_ctx_allocated; /* true if decoding context allocated */