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bitstream reader optimize patch by (BERO <bero at geocities dot co dot jp>)

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Originally committed as revision 1871 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
BERO
2003-05-14 00:32:22 +00:00
committed by Michael Niedermayer
parent 7062fad6e9
commit d8e00c0997
4 changed files with 72 additions and 19 deletions
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57
libavcodec/common.h
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@@ -16,6 +16,7 @@
#define ALT_BITSTREAM_READER
//#define LIBMPEG2_BITSTREAM_READER
//#define A32_BITSTREAM_READER
#define LIBMPEG2_BITSTREAM_READER_HACK //add BERO
#ifdef HAVE_AV_CONFIG_H
/* only include the following when compiling package */
@@ -472,6 +473,16 @@ LAST_SKIP_BITS(name, gb, num)
for examples see get_bits, show_bits, skip_bits, get_vlc
*/
static inline int unaligned32_be(const void *v)
{
#ifdef CONFIG_ALIGN
const uint8_t *p=v;
return (((p[0]<<8) | p[1])<<16) | (p[2]<<8) | (p[3]);
#else
return be2me_32( unaligned32(v)); //original
#endif
}
#ifdef ALT_BITSTREAM_READER
# define MIN_CACHE_BITS 25
@@ -483,7 +494,7 @@ for examples see get_bits, show_bits, skip_bits, get_vlc
(gb)->index= name##_index;\
# define UPDATE_CACHE(name, gb)\
name##_cache= be2me_32( unaligned32( ((uint8_t *)(gb)->buffer)+(name##_index>>3) ) ) << (name##_index&0x07);\
name##_cache= unaligned32_be( ((uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
# define SKIP_CACHE(name, gb, num)\
name##_cache <<= (num);\
@@ -528,6 +539,17 @@ static inline int get_bits_count(GetBitContext *s){
(gb)->cache= name##_cache;\
(gb)->buffer_ptr= name##_buffer_ptr;\
#ifdef LIBMPEG2_BITSTREAM_READER_HACK
# define UPDATE_CACHE(name, gb)\
if(name##_bit_count >= 0){\
name##_cache+= (int)be2me_16(*(uint16_t*)name##_buffer_ptr++) << name##_bit_count;\
name##_buffer_ptr+=2;\
name##_bit_count-= 16;\
}\
#else
# define UPDATE_CACHE(name, gb)\
if(name##_bit_count > 0){\
name##_cache+= ((name##_buffer_ptr[0]<<8) + name##_buffer_ptr[1]) << name##_bit_count;\
@@ -535,6 +557,8 @@ static inline int get_bits_count(GetBitContext *s){
name##_bit_count-= 16;\
}\
#endif
# define SKIP_CACHE(name, gb, num)\
name##_cache <<= (num);\
@@ -630,6 +654,37 @@ static inline int get_bits_count(GetBitContext *s){
#endif
/* add BERO
if MSB not set it is negative
*/
static inline int get_xbits(GetBitContext *s, int n){
register int tmp;
register int32_t cache;
OPEN_READER(re, s)
UPDATE_CACHE(re, s)
cache = GET_CACHE(re,s);
if ((int32_t)cache<0) { //MSB=1
tmp = NEG_USR32(cache,n);
} else {
// tmp = (-1<<n) | NEG_USR32(cache,n) + 1; mpeg12.c algo
// tmp = - (NEG_USR32(cache,n) ^ ((1 << n) - 1)); h263.c algo
tmp = - NEG_USR32(~cache,n);
}
LAST_SKIP_BITS(re, s, n)
CLOSE_READER(re, s)
return tmp;
}
static inline int get_sbits(GetBitContext *s, int n){
register int tmp;
OPEN_READER(re, s)
UPDATE_CACHE(re, s)
tmp= SHOW_SBITS(re, s, n);
LAST_SKIP_BITS(re, s, n)
CLOSE_READER(re, s)
return tmp;
}
static inline unsigned int get_bits(GetBitContext *s, int n){
register int tmp;
OPEN_READER(re, s)