diff options
author | Michael Niedermayer <michaelni@gmx.at> | 2004-10-26 07:12:21 +0400 |
---|---|---|
committer | Michael Niedermayer <michaelni@gmx.at> | 2004-10-26 07:12:21 +0400 |
commit | ec7eb8966c6bba4883c8c798ed14e669a71bd379 (patch) | |
tree | df95186696540d4c7c151b82eddb45c88fbc4fed /libavcodec/cabac.c | |
parent | 9297ddd32e89f9e2e5884edd659892607cea455a (diff) |
optimization
Originally committed as revision 3639 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/cabac.c')
-rw-r--r-- | libavcodec/cabac.c | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/libavcodec/cabac.c b/libavcodec/cabac.c index 9d56e23fc7..915c057114 100644 --- a/libavcodec/cabac.c +++ b/libavcodec/cabac.c @@ -69,6 +69,25 @@ const uint8_t ff_h264_lps_state[64]= { 36,36,37,37,37,38,38,63, }; +const uint8_t ff_h264_norm_shift[256]= { + 8,7,6,6,5,5,5,5,4,4,4,4,4,4,4,4, + 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, + 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, + 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, + 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, + 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, + 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, +}; + /** * * @param buf_size size of buf in bits @@ -95,10 +114,14 @@ void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){ c->bytestream= buf; c->bytestream_end= buf + buf_size; - c->low= *c->bytestream++; - c->low= (c->low<<9) + ((*c->bytestream++)<<1); - c->range= 0x1FE00; - c->bits_left= 7; +#if CABAC_BITS == 16 + c->low = (*c->bytestream++)<<18; + c->low+= (*c->bytestream++)<<10; +#else + c->low = (*c->bytestream++)<<10; +#endif + c->low+= ((*c->bytestream++)<<2) + 2; + c->range= 0x1FE<<(CABAC_BITS + 1); } void ff_init_cabac_states(CABACContext *c, uint8_t const (*lps_range)[4], @@ -107,8 +130,8 @@ void ff_init_cabac_states(CABACContext *c, uint8_t const (*lps_range)[4], for(i=0; i<state_count; i++){ for(j=0; j<4; j++){ //FIXME check if this is worth the 1 shift we save - c->lps_range[2*i+0][j]= - c->lps_range[2*i+1][j]= lps_range[i][j]; + c->lps_range[2*i+0][j+4]= + c->lps_range[2*i+1][j+4]= lps_range[i][j]; } c->mps_state[2*i+0]= 2*mps_state[i]; |