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ffmpeg.wasm-core
Commit 78486403 authored by Michael Niedermayer's avatar Michael Niedermayer
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use parent sample to predict significance & magnitude 

1% bitrate reduction (foreman@352x288 qscale 1 & 8)

Originally committed as revision 3352 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent c07a22fb
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Showing with 28 additions and 10 deletions
libavcodec/snow.c
View file @ 78486403
......@@ -1419,7 +1419,7 @@ static void encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *pa
for(y=0; y<h; y++){
for(x=0; x<w; x++){
int v, p;
int v, p=0;
int /*ll=0, */l=0, lt=0, t=0, rt=0;
if(orientation==1) v= src[y + x*stride];
else v= src[x + y*stride];
......@@ -1444,7 +1444,13 @@ static void encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *pa
else ll= src[x - 2 + y*stride];
}*/
}
if(!(/*ll|*/l|lt|t|rt)){
if(parent){
int px= (orientation==1 ? y : x)>>1;
int py= (orientation==1 ? x : y)>>1;
if(px<b->parent->width && py<b->parent->height)
p= parent[px + py*2*stride];
}
if(!(/*ll|*/l|lt|t|rt|p)){
if(v){
runs[run_index++]= run;
run=0;
......@@ -1462,7 +1468,7 @@ static void encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *pa
for(y=0; y<h; y++){
for(x=0; x<w; x++){
int v, p;
int v, p=0;
int /*ll=0, */l=0, lt=0, t=0, rt=0;
if(orientation==1) v= src[y + x*stride];
else v= src[x + y*stride];
......@@ -1487,8 +1493,14 @@ static void encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *pa
else ll= src[x - 2 + y*stride];
}*/
}
if(/*ll|*/l|lt|t|rt){
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt));
if(parent){
int px= (orientation==1 ? y : x)>>1;
int py= (orientation==1 ? x : y)>>1;
if(px<b->parent->width && py<b->parent->height)
p= parent[px + py*2*stride];
}
if(/*ll|*/l|lt|t|rt|p){
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt) + ABS(p));
put_cabac(&s->c, &b->state[0][context], !!v);
}else{
......@@ -1502,7 +1514,7 @@ static void encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *pa
}
}
if(v){
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt));
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt) + ABS(p));
put_symbol(&s->c, b->state[context + 2], ABS(v)-1, 0);
put_cabac(&s->c, &b->state[0][16 + 1 + 3 + quant3b[l&0xFF] + 3*quant3b[t&0xFF]], v<0);
......@@ -1642,7 +1654,7 @@ static inline void decode_subbandX(SnowContext *s, SubBand *b, DWTELEM *src, DWT
run= get_symbol(&s->c, b->state[1], 0);
for(y=0; y<h; y++){
for(x=0; x<w; x++){
int v, p;
int v, p=0;
int /*ll=0, */l=0, lt=0, t=0, rt=0;
if(y){
......@@ -1665,8 +1677,14 @@ static inline void decode_subbandX(SnowContext *s, SubBand *b, DWTELEM *src, DWT
else ll= src[x - 2 + y*stride];
}*/
}
if(/*ll|*/l|lt|t|rt){
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt));
if(parent){
int px= (orientation==1 ? y : x)>>1;
int py= (orientation==1 ? x : y)>>1;
if(px<b->parent->width && py<b->parent->height)
p= parent[px + py*2*stride];
}
if(/*ll|*/l|lt|t|rt|p){
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt) + ABS(p));
v=get_cabac(&s->c, &b->state[0][context]);
}else{
......@@ -1681,7 +1699,7 @@ static inline void decode_subbandX(SnowContext *s, SubBand *b, DWTELEM *src, DWT
}
}
if(v){
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt));
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt) + ABS(p));
v= get_symbol(&s->c, b->state[context + 2], 0) + 1;
if(get_cabac(&s->c, &b->state[0][16 + 1 + 3 + quant3b[l&0xFF] + 3*quant3b[t&0xFF]]))
v= -v;
......
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