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better context model (0.2-1% lower bitrate)

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a tiny bit cleanup

Originally committed as revision 3348 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2004-07-27 01:30:44 +00:00
parent 9dac77a7aa
commit 6b2f664691
1 changed files with 30 additions and 23 deletions
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53
libavcodec/snow.c
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@ -1420,7 +1420,7 @@ 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 l=0, t=0, lt=0, rt=0/*, pri2=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];
@ -1439,12 +1439,12 @@ static void encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *pa
if(x){
if(orientation==1) l= src[y + (x-1)*stride];
else l= src[x - 1 + y*stride];
/* if(x > 1){
if(orientation==1) pri2= src[y + (x-2)*stride];
else pri2= src[x - 2 + y*stride];
/*if(x > 1){
if(orientation==1) ll= src[y + (x-2)*stride];
else ll= src[x - 2 + y*stride];
}*/
}
if(!(lt|rt|t|l)){
if(!(/*ll|*/l|lt|t|rt)){
if(v){
runs[run_index++]= run;
run=0;
@ -1458,12 +1458,12 @@ static void encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *pa
run_index=0;
run= runs[run_index++];
put_symbol(&s->c, b->state[1+7], run, 0);
put_symbol(&s->c, b->state[1], run, 0);
for(y=0; y<h; y++){
for(x=0; x<w; x++){
int v, p;
int l=0, t=0, lt=0, rt=0/*, pri2=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];
@ -1482,17 +1482,19 @@ static void encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *pa
if(x){
if(orientation==1) l= src[y + (x-1)*stride];
else l= src[x - 1 + y*stride];
/* if(x > 1){
if(orientation==1) pri2= src[y + (x-2)*stride];
else pri2= src[x - 2 + y*stride];
/*if(x > 1){
if(orientation==1) ll= src[y + (x-2)*stride];
else ll= src[x - 2 + y*stride];
}*/
}
if(lt|rt|t|l){
put_cabac(&s->c, &b->state[0][(!l) + 2*(!t) + 4*(!lt) + 8*(!rt)], !v);
if(/*ll|*/l|lt|t|rt){
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt));
put_cabac(&s->c, &b->state[0][context], !!v);
}else{
if(!run){
run= runs[run_index++];
put_symbol(&s->c, b->state[1+7], run, 0);
put_symbol(&s->c, b->state[1], run, 0);
assert(v);
}else{
run--;
@ -1500,7 +1502,9 @@ static void encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *pa
}
}
if(v){
put_symbol(&s->c, b->state[quant13[(ABS(l) + ABS(t))&0x7F] + 1], ABS(v)-1, 0);
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt));
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);
}
}
@ -1635,11 +1639,11 @@ static inline void decode_subbandX(SnowContext *s, SubBand *b, DWTELEM *src, DWT
h= b->height;
}
x=y=0;
run= get_symbol(&s->c, b->state[1+7], 0);
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 l=0, t=0, lt=0, rt=0/*, pri2=0*/;
int /*ll=0, */l=0, lt=0, t=0, rt=0;
if(y){
if(orientation==1) t= src[y - 1 + x*stride];
@ -1656,16 +1660,18 @@ static inline void decode_subbandX(SnowContext *s, SubBand *b, DWTELEM *src, DWT
if(x){
if(orientation==1) l= src[y + (x-1)*stride];
else l= src[x - 1 + y*stride];
/* if(x > 1){
if(orientation==1) pri2= src[y + (x-2)*stride];
else pri2= src[x - 2 + y*stride];
/*if(x > 1){
if(orientation==1) ll= src[y + (x-2)*stride];
else ll= src[x - 2 + y*stride];
}*/
}
if(lt|rt|t|l){
v=!get_cabac(&s->c, &b->state[0][(!l) + 2*(!t) + 4*(!lt) + 8*(!rt)]);
if(/*ll|*/l|lt|t|rt){
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt));
v=get_cabac(&s->c, &b->state[0][context]);
}else{
if(!run){
run= get_symbol(&s->c, b->state[1+7], 0);
run= get_symbol(&s->c, b->state[1], 0);
//FIXME optimize this here
//FIXME try to store a more naive run
v=1;
@ -1675,7 +1681,8 @@ static inline void decode_subbandX(SnowContext *s, SubBand *b, DWTELEM *src, DWT
}
}
if(v){
v= get_symbol(&s->c, b->state[quant13[(ABS(l) + ABS(t))&0x7F] + 1], 0) + 1;
int context= av_log2(/*ABS(ll) + */3*ABS(l) + ABS(lt) + 2*ABS(t) + ABS(rt));
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;
if(orientation==1) src[y + x*stride]= v;