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Try to find a bit better initial states in ffv1 2pass.

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Difference in filesizes to foreman ffv1 version=2, context=1 coder=1
18637016 adv-pass2-g300.avi
18638806 adv-pass1-g300.avi
18640534 ref-pass2-g300.avi
18918214 adv-pass2-g1.avi
18982048 ref-pass2-g1.avi
21516230 adv-pass1-g1.avi

Originally committed as revision 25594 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2010-10-28 12:15:47 +00:00
parent 0ae0faa7c0
commit 73cbf86830
1 changed files with 48 additions and 4 deletions
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52
libavcodec/ffv1.c
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@ -302,6 +302,48 @@ static inline int get_context(PlaneContext *p, int_fast16_t *src, int_fast16_t *
return p->quant_table[0][(L-LT) & 0xFF] + p->quant_table[1][(LT-T) & 0xFF] + p->quant_table[2][(T-RT) & 0xFF];
}
static void find_best_state(uint8_t best_state[256][256], const uint8_t one_state[256]){
int i,j,k,m;
double l2tab[256];
for(i=1; i<256; i++)
l2tab[i]= log2(i/256.0);
for(i=0; i<256; i++){
double best_len[256];
double p= i/256.0;
for(j=0; j<256; j++)
best_len[j]= 1<<30;
for(j=FFMAX(i-10,1); j<FFMIN(i+11,256); j++){
double occ[256]={0};
double len=0;
occ[j]=1.0;
for(k=0; k<256; k++){
double newocc[256]={0};
for(m=0; m<256; m++){
if(occ[m]){
len -=occ[m]*( p *l2tab[ m]
+ (1-p)*l2tab[256-m]);
}
}
if(len < best_len[k]){
best_len[k]= len;
best_state[i][k]= j;
}
for(m=0; m<256; m++){
if(occ[m]){
newocc[ one_state[ m]] += occ[m]* p ;
newocc[256-one_state[256-m]] += occ[m]*(1-p);
}
}
memcpy(occ, newocc, sizeof(occ));
}
}
}
}
static av_always_inline av_flatten void put_symbol_inline(RangeCoder *c, uint8_t *state, int v, int is_signed, uint64_t rc_stat[256][2], uint64_t rc_stat2[32][2]){
int i;
@ -961,6 +1003,7 @@ static av_cold int encode_init(AVCodecContext *avctx)
}
if(avctx->stats_in){
char *p= avctx->stats_in;
uint8_t best_state[256][256];
int gob_count=0;
char *next;
@ -1002,15 +1045,16 @@ static av_cold int encode_init(AVCodecContext *avctx)
}
sort_stt(s, s->state_transition);
find_best_state(best_state, s->state_transition);
for(i=0; i<s->quant_table_count; i++){
for(j=0; j<s->context_count[i]; j++){
for(k=0; k<32; k++){
int p= 128;
double p= 128;
if(s->rc_stat2[i][j][k][0]+s->rc_stat2[i][j][k][1]){
p=256*s->rc_stat2[i][j][k][1] / (s->rc_stat2[i][j][k][0]+s->rc_stat2[i][j][k][1]);
p=256.0*s->rc_stat2[i][j][k][1] / (s->rc_stat2[i][j][k][0]+s->rc_stat2[i][j][k][1]);
}
p= av_clip(p, 1, 254);
s->initial_states[i][j][k]= p;
s->initial_states[i][j][k]= best_state[av_clip(round(p), 1, 255)][av_clip((s->rc_stat2[i][j][k][0]+s->rc_stat2[i][j][k][1])/gob_count, 0, 255)];
}
}
}