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| author | Michael Niedermayer <michaelni@gmx.at> | 2013-02-07 19:39:08 +0100 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2013-02-07 19:46:02 +0100 |
| commit | a00c4b4db044b54296af14eeffe7989ac67e4197 (patch) | |
| tree | 945f439b4042839c99794f973f600e5a5c69e45d | |
| parent | 9f956611e33f73f6ad8d926e8a361e75aa42a491 (diff) | |
| download | ffmpeg-a00c4b4db044b54296af14eeffe7989ac67e4197.tar.gz | |
af_biquad: avoid subtraction in loop
17% faster
Note the speedup is smaller if its done before
storing in the context (gcc 4.6.3 core i7)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
| -rw-r--r-- | libavfilter/af_biquads.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/libavfilter/af_biquads.c b/libavfilter/af_biquads.c index 1f4d635585..de0ba4248e 100644 --- a/libavfilter/af_biquads.c +++ b/libavfilter/af_biquads.c @@ -181,9 +181,11 @@ static void biquad_## name (const void *input, void *output, int len, \ double o1 = *out1; \ double o2 = *out2; \ int i; \ + a1 = -a1; \ + a2 = -a2; \ \ for (i = 0; i+1 < len; i++) { \ - o2 = i2 * b2 + i1 * b1 + ibuf[i] * b0 - o2 * a2 - o1 * a1; \ + o2 = i2 * b2 + i1 * b1 + ibuf[i] * b0 + o2 * a2 + o1 * a1; \ i2 = ibuf[i]; \ if (o2 < min) { \ av_log(NULL, AV_LOG_WARNING, "clipping\n"); \ @@ -195,7 +197,7 @@ static void biquad_## name (const void *input, void *output, int len, \ obuf[i] = o2; \ } \ i++; \ - o1 = i1 * b2 + i2 * b1 + ibuf[i] * b0 - o1 * a2 - o2 * a1; \ + o1 = i1 * b2 + i2 * b1 + ibuf[i] * b0 + o1 * a2 + o2 * a1; \ i1 = ibuf[i]; \ if (o1 < min) { \ av_log(NULL, AV_LOG_WARNING, "clipping\n"); \ @@ -208,7 +210,7 @@ static void biquad_## name (const void *input, void *output, int len, \ } \ } \ if (i < len) { \ - double o0 = ibuf[i] * b0 + i1 * b1 + i2 * b2 - o1 * a1 - o2 * a2; \ + double o0 = ibuf[i] * b0 + i1 * b1 + i2 * b2 + o1 * a1 + o2 * a2; \ i2 = i1; \ i1 = ibuf[i]; \ o2 = o1; \ |