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Change to a 64 bit accumulation variable instead of shifting. 

Changing the way the loop is done is necessary to reduce register pressure.
About 20% speedup even on 32 bit x86.


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@25103 b3059339-0415-0410-9bf9-f77b7e298cf2
This commit is contained in:
reimar 2007-11-18 18:52:51 +00:00
parent 13a205e075
commit 0f0e2f5f5b
1 changed files with 5 additions and 5 deletions
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10
libaf/af_scaletempo.c
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@ -69,7 +69,6 @@ typedef struct af_scaletempo_s
void* buf_pre_corr;
void* table_window;
int (*best_overlap_offset)(struct af_scaletempo_s* s);
short shift_corr;
// command line
float scale_nominal;
float ms_stride;
@ -153,7 +152,7 @@ static int best_overlap_offset_s16(af_scaletempo_t* s)
{
int32_t *pw, *ppc;
int16_t *po, *search_start;
int32_t best_corr = INT_MIN;
int64_t best_corr = INT64_MIN;
int best_off = 0;
int off;
long i;
@ -168,12 +167,14 @@ static int best_overlap_offset_s16(af_scaletempo_t* s)
search_start = (int16_t*)s->buf_queue + s->num_channels;
for (off=0; off<s->frames_search; off++) {
int32_t corr = 0;
int64_t corr = 0;
int16_t* ps = search_start;
ppc = s->buf_pre_corr;
ppc += s->samples_overlap - s->num_channels;
ps += s->samples_overlap - s->num_channels;
i = -(s->samples_overlap - s->num_channels);
do {
corr += ( *ppc++ * *ps++ ) >> s->shift_corr;
corr += ppc[i] * ps[i];
} while (++i < 0);
if (corr > best_corr) {
best_corr = corr;
@ -380,7 +381,6 @@ static int control(struct af_instance_s* af, int cmd, void* arg)
*pw++ = v;
}
}
s->shift_corr = av_log2( 2*(s->samples_overlap - nch) - 1 );
s->best_overlap_offset = best_overlap_offset_s16;
} else {
float* pw;