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(commited by michael / arpi was crazy enough to give me his password) 

fixed a bug in get_vlc() when using the ALT_BITSTREAM_READER (rv10 & mpeg12 decoders where not working)
some optimizations
 replaced a if() with a >>
 changed get_bits1() a bit so it hopefully is faster on p4

Originally committed as revision 259 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2002-01-12 20:21:51 +00:00
parent eede215681
commit 05f361f0c7
1 changed files with 38 additions and 12 deletions
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50
libavcodec/common.h
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@ -10,6 +10,7 @@
//#define ALT_BITSTREAM_READER
//#define ALIGNED_BITSTREAM
#define FAST_GET_FIRST_VLC
#ifdef HAVE_AV_CONFIG_H
/* only include the following when compiling package */
@ -244,8 +245,8 @@ static inline unsigned int get_bits(GetBitContext *s, int n){
: "0" (result1), "r" (result2), "c" (index));
#else
result1<<= (index&0x1F);
result2>>= 32-(index&0x1F);
if((index&0x1F)!=0) result1|= result2;
result2= (result2>>1) >> (31-(index&0x1F));
result1|= result2;
#endif
result1>>= 32 - n;
index+= n;
@ -282,8 +283,8 @@ static inline unsigned int get_bits1(GetBitContext *s){
#ifdef ALT_BITSTREAM_READER
int index= s->index;
uint8_t result= s->buffer[ index>>3 ];
result>>= 7-(index&0x07);
result&=1;
result<<= (index&0x07);
result>>= 8 - 1;
index++;
s->index= index;
@ -319,8 +320,8 @@ static inline unsigned int show_bits(GetBitContext *s, int n)
: "0" (result1), "r" (result2), "c" (index));
#else
result1<<= (index&0x1F);
result2>>= 32-(index&0x1F);
if((index&0x1F)!=0) result1|= result2;
result2= (result2>>1) >> (31-(index&0x1F));
result1|= result2;
#endif
result1>>= 32 - n;
@ -394,10 +395,33 @@ int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
void free_vlc(VLC *vlc);
#ifdef ALT_BITSTREAM_READER
#define SHOW_BITS(s, val, n) val= show_bits(s, n);
#define FLUSH_BITS(n) skip_bits(s, n);
#define SAVE_BITS(s) ;
#define RESTORE_BITS(s) ;
#ifdef ALIGNED_BITSTREAM
#ifdef ARCH_X86
#define SHOW_BITS(s, val, n) \
val= be2me_32( ((uint32_t *)(s)->buffer)[bit_cnt>>5] );\
{uint32_t result2= be2me_32( ((uint32_t *)(s)->buffer)[(bit_cnt>>5) + 1] );\
asm ("shldl %%cl, %2, %0\n\t"\
: "=r" (val)\
: "0" (val), "r" (result2), "c" (bit_cnt));\
((uint32_t)val)>>= 32 - n;}
#else //ARCH_X86
#define SHOW_BITS(s, val, n) \
val= be2me_32( ((uint32_t *)(s)->buffer)[bit_cnt>>5] );\
{uint32_t result2= be2me_32( ((uint32_t *)(s)->buffer)[(bit_cnt>>5) + 1] );\
val<<= (bit_cnt&0x1F);\
result2= (result2>>1) >> (31-(bit_cnt&0x1F));\
val|= result2;\
((uint32_t)val)>>= 32 - n;}
#endif //!ARCH_X86
#else //ALIGNED_BITSTREAM
#define SHOW_BITS(s, val, n) \
val= be2me_32( unaligned32( ((uint8_t *)(s)->buffer)+(bit_cnt>>3) ) );\
val<<= (bit_cnt&0x07);\
((uint32_t)val)>>= 32 - n;
#endif // !ALIGNED_BITSTREAM
#define FLUSH_BITS(n) bit_cnt+=n;
#define SAVE_BITS(s) bit_cnt= (s)->index;
#define RESTORE_BITS(s) (s)->index= bit_cnt;
#else
/* macro to go faster */
@ -447,8 +471,8 @@ static inline int get_vlc(GetBitContext *s, VLC *vlc)
int code, n, nb_bits, index;
INT16 *table_codes;
INT8 *table_bits;
#ifndef ALT_BITSTREAM_READER
int bit_cnt;
#ifndef ALT_BITSTREAM_READER
UINT32 bit_buf;
UINT8 *buf_ptr;
#endif
@ -457,7 +481,8 @@ static inline int get_vlc(GetBitContext *s, VLC *vlc)
nb_bits = vlc->bits;
table_codes = vlc->table_codes;
table_bits = vlc->table_bits;
#ifdef FAST_GET_FIRST_VLC
SHOW_BITS(s, index, nb_bits);
code = table_codes[index];
n = table_bits[index];
@ -474,6 +499,7 @@ static inline int get_vlc(GetBitContext *s, VLC *vlc)
table_codes = vlc->table_codes + code;
table_bits = vlc->table_bits + code;
}
#endif
for(;;) {
SHOW_BITS(s, index, nb_bits);
code = table_codes[index];