From 2fe4700f761e21788dd3c23c7eca9dc0d436ef10 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Sun, 26 May 2013 18:50:13 -0400
Subject: [PATCH] Skip down-sampling in deemphasis() when not needed.
---
celt/celt_decoder.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/celt/celt_decoder.c b/celt/celt_decoder.c
index d5d2c57f9..cfb5b36d9 100644
--- a/celt/celt_decoder.c
+++ b/celt/celt_decoder.c
@@ -191,6 +191,7 @@ void deemphasis(celt_sig *in[], opus_val16 *pcm, int N, int C, int downsample, c
{
int c;
int Nd;
+ int apply_downsampling=0;
opus_val16 coef0;
coef0 = coef[0];
@@ -215,8 +216,10 @@ void deemphasis(celt_sig *in[], opus_val16 *pcm, int N, int C, int downsample, c
tmp = SHL32(MULT16_32_Q15(coef3, tmp), 2);
scratch[j] = tmp;
}
+ apply_downsampling=1;
} else
#endif
+ if (downsample>1)
{
/* Shortcut for the standard (non-custom modes) case */
for (j=0;j<N;j++)
@@ -225,12 +228,24 @@ void deemphasis(celt_sig *in[], opus_val16 *pcm, int N, int C, int downsample, c
m = MULT16_32_Q15(coef0, tmp);
scratch[j] = tmp;
}
+ apply_downsampling=1;
+ } else {
+ /* Shortcut for the standard (non-custom modes) case */
+ for (j=0;j<N;j++)
+ {
+ celt_sig tmp = x[j] + m;
+ m = MULT16_32_Q15(coef0, tmp);
+ y[j*C] = SCALEOUT(SIG2WORD16(tmp));
+ }
}
mem[c] = m;
- /* Perform down-sampling */
- for (j=0;j<Nd;j++)
- y[j*C] = SCALEOUT(SIG2WORD16(scratch[j*downsample]));
+ if (apply_downsampling)
+ {
+ /* Perform down-sampling */
+ for (j=0;j<Nd;j++)
+ y[j*C] = SCALEOUT(SIG2WORD16(scratch[j*downsample]));
+ }
} while (++c<C);
}
--
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