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ffmpeg
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make state transition tables global as they are constant and the code is slightly faster that way 

Originally committed as revision 6655 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-10-11 14:44:17 +00:00
parent 5f3eca121e
commit d61c4e731e
3 changed files with 31 additions and 35 deletions
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31
libavcodec/cabac.c
View File

@ -51,8 +51,10 @@ static const uint8_t lps_range[64][4]= {
};
uint8_t ff_h264_lps_range[2*65][4];
uint8_t ff_h264_lps_state[2*64];
uint8_t ff_h264_mps_state[2*64];
const uint8_t ff_h264_mps_state[64]= {
static const uint8_t mps_state[64]= {
1, 2, 3, 4, 5, 6, 7, 8,
9,10,11,12,13,14,15,16,
17,18,19,20,21,22,23,24,
@ -63,7 +65,7 @@ const uint8_t ff_h264_mps_state[64]= {
57,58,59,60,61,62,62,63,
};
const uint8_t ff_h264_lps_state[64]= {
static const uint8_t lps_state[64]= {
0, 0, 1, 2, 2, 4, 4, 5,
6, 7, 8, 9, 9,11,11,12,
13,13,15,15,16,16,18,18,
@ -121,32 +123,31 @@ void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){
c->range= 0x1FE<<(CABAC_BITS + 1);
}
void ff_init_cabac_states(CABACContext *c,
uint8_t const *mps_state, uint8_t const *lps_state, int state_count){
void ff_init_cabac_states(CABACContext *c){
int i, j;
for(i=0; i<state_count; i++){
for(i=0; i<64; i++){
for(j=0; j<4; j++){ //FIXME check if this is worth the 1 shift we save
ff_h264_lps_range[2*i+0][j+4]=
ff_h264_lps_range[2*i+1][j+4]= lps_range[i][j];
}
c->mps_state[2*i+0]= 2*mps_state[i]+0;
c->mps_state[2*i+1]= 2*mps_state[i]+1;
ff_h264_mps_state[2*i+0]= 2*mps_state[i]+0;
ff_h264_mps_state[2*i+1]= 2*mps_state[i]+1;
if( i ){
#ifdef BRANCHLESS_CABAC_DECODER
c->mps_state[-2*i-1]= 2*lps_state[i]+0; //FIXME yes this is not valid C but iam lazy, cleanup welcome
c->mps_state[-2*i-2]= 2*lps_state[i]+1;
ff_h264_mps_state[-2*i-1]= 2*lps_state[i]+0; //FIXME yes this is not valid C but iam lazy, cleanup welcome
ff_h264_mps_state[-2*i-2]= 2*lps_state[i]+1;
}else{
c->mps_state[-2*i-1]= 1;
c->mps_state[-2*i-2]= 0;
ff_h264_mps_state[-2*i-1]= 1;
ff_h264_mps_state[-2*i-2]= 0;
#else
c->lps_state[2*i+0]= 2*lps_state[i]+0;
c->lps_state[2*i+1]= 2*lps_state[i]+1;
ff_h264_lps_state[2*i+0]= 2*lps_state[i]+0;
ff_h264_lps_state[2*i+1]= 2*lps_state[i]+1;
}else{
c->lps_state[2*i+0]= 1;
c->lps_state[2*i+1]= 0;
ff_h264_lps_state[2*i+0]= 1;
ff_h264_lps_state[2*i+1]= 0;
#endif
}
}

33
libavcodec/cabac.h
View File

@ -41,8 +41,6 @@ typedef struct CABACContext{
#ifdef STRICT_LIMITS
int symCount;
#endif
uint8_t lps_state[2*64]; ///< transIdxLPS
uint8_t mps_state[2*64]; ///< transIdxMPS
const uint8_t *bytestream_start;
const uint8_t *bytestream;
const uint8_t *bytestream_end;
@ -50,15 +48,14 @@ typedef struct CABACContext{
}CABACContext;
extern uint8_t ff_h264_lps_range[2*65][4]; ///< rangeTabLPS
extern const uint8_t ff_h264_mps_state[64];
extern const uint8_t ff_h264_lps_state[64];
extern uint8_t ff_h264_mps_state[2*64]; ///< transIdxMPS
extern uint8_t ff_h264_lps_state[2*64]; ///< transIdxLPS
extern const uint8_t ff_h264_norm_shift[128];
void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size);
void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size);
void ff_init_cabac_states(CABACContext *c,
uint8_t const *mps_state, uint8_t const *lps_state, int state_count);
void ff_init_cabac_states(CABACContext *c);
static inline void put_cabac_bit(CABACContext *c, int b){
@ -91,11 +88,11 @@ static void put_cabac(CABACContext *c, uint8_t * const state, int bit){
if(bit == ((*state)&1)){
c->range -= RangeLPS;
*state= c->mps_state[*state];
*state= ff_h264_mps_state[*state];
}else{
c->low += c->range - RangeLPS;
c->range = RangeLPS;
*state= c->lps_state[*state];
*state= ff_h264_lps_state[*state];
}
renorm_cabac_encoder(c);
@ -369,11 +366,9 @@ static int get_cabac(CABACContext *c, uint8_t * const state){
#define LOW "0"
#define RANGE "4"
#define LPS_STATE "12"
#define MPS_STATE "12+2*64"
#define BYTESTART "12+4*64"
#define BYTE "16+4*64"
#define BYTEEND "20+4*64"
#define BYTESTART "12"
#define BYTE "16"
#define BYTEEND "20"
#ifndef BRANCHLESS_CABAC_DECODER
asm volatile(
"movzbl (%1), %%eax \n\t"
@ -391,7 +386,7 @@ static int get_cabac(CABACContext *c, uint8_t * const state){
"setb %%cl \n\t"
"shl %%cl, %%edx \n\t"
"shl %%cl, %%ebx \n\t"
"movzbl "MPS_STATE"(%2, %%eax), %%ecx \n\t"
"movzbl "MANGLE(ff_h264_mps_state)"(%%eax), %%ecx \n\t"
"movb %%cl, (%1) \n\t"
//eax:state ebx:low, edx:range, esi:RangeLPS
"test %%bx, %%bx \n\t"
@ -413,7 +408,7 @@ static int get_cabac(CABACContext *c, uint8_t * const state){
"movzbl " MANGLE(ff_h264_norm_shift) "(%%esi), %%ecx \n\t"
"shll %%cl, %%ebx \n\t"
"shll %%cl, %%edx \n\t"
"movzbl "LPS_STATE"(%2, %%eax), %%ecx \n\t"
"movzbl "MANGLE(ff_h264_lps_state)"(%%eax), %%ecx \n\t"
"movb %%cl, (%1) \n\t"
"addl $1, %%eax \n\t"
"test %%bx, %%bx \n\t"
@ -475,7 +470,7 @@ static int get_cabac(CABACContext *c, uint8_t * const state){
#endif
//eax:state ebx:low edx:mask esi:range
"movzbl "MPS_STATE"(%2, %%eax), %%ecx \n\t"
"movzbl "MANGLE(ff_h264_mps_state)"(%%eax), %%ecx \n\t"
"movb %%cl, (%1) \n\t"
"movl %%esi, %%edx \n\t"
@ -523,12 +518,12 @@ static int get_cabac(CABACContext *c, uint8_t * const state){
#ifndef BRANCHLESS_CABAC_DECODER
if(c->low < c->range){
bit= s&1;
*state= c->mps_state[s];
*state= ff_h264_mps_state[s];
renorm_cabac_decoder_once(c);
}else{
bit= ff_h264_norm_shift[RangeLPS>>19];
c->low -= c->range;
*state= c->lps_state[s];
*state= ff_h264_lps_state[s];
c->range = RangeLPS<<bit;
c->low <<= bit;
bit= (s&1)^1;
@ -544,7 +539,7 @@ static int get_cabac(CABACContext *c, uint8_t * const state){
c->range += (RangeLPS - c->range) & lps_mask;
s^=lps_mask;
*state= c->mps_state[s];
*state= ff_h264_mps_state[s];
bit= s&1;
lps_mask= ff_h264_norm_shift[c->range>>(CABAC_BITS+3)];

2
libavcodec/h264.c
View File

@ -7388,7 +7388,7 @@ static int decode_slice(H264Context *h){
align_get_bits( &s->gb );
/* init cabac */
ff_init_cabac_states( &h->cabac, ff_h264_mps_state, ff_h264_lps_state, 64 );
ff_init_cabac_states( &h->cabac);
ff_init_cabac_decoder( &h->cabac,
s->gb.buffer + get_bits_count(&s->gb)/8,
( s->gb.size_in_bits - get_bits_count(&s->gb) + 7)/8);