From c8ce2ef3918c1c83109be015b5f51b253c1f9a58 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Thu, 25 Oct 2012 14:44:37 -0400
Subject: [PATCH] Keeping the deemphasis coefficients in local variable to
avoid aliasing issues
---
celt/celt.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/celt/celt.c b/celt/celt.c
index 91f7dfe1c..1c4aedbef 100644
--- a/celt/celt.c
+++ b/celt/celt.c
@@ -572,6 +572,10 @@ static void deemphasis(celt_sig *in[], opus_val16 *pcm, int N, int C, int downsa
{
int c;
int Nd;
+ opus_val16 coef0, coef1;
+
+ coef0 = coef[0];
+ coef1 = coef[1];
Nd = N/downsample;
c=0; do {
int j;
@@ -581,21 +585,22 @@ static void deemphasis(celt_sig *in[], opus_val16 *pcm, int N, int C, int downsa
x =in[c];
y = pcm+c;
/* Shortcut for the standard (non-custom modes) case */
- if (coef[1] == 0)
+ if (coef1 == 0)
{
for (j=0;j<N;j++)
{
celt_sig tmp = x[j] + m;
- m = MULT16_32_Q15(coef[0], tmp);
+ m = MULT16_32_Q15(coef0, tmp);
scratch[j] = tmp;
}
} else {
+ opus_val16 coef3 = coef[3];
for (j=0;j<N;j++)
{
celt_sig tmp = x[j] + m;
- m = MULT16_32_Q15(coef[0], tmp)
- - MULT16_32_Q15(coef[1], x[j]);
- tmp = SHL32(MULT16_32_Q15(coef[3], tmp), 2);
+ m = MULT16_32_Q15(coef0, tmp)
+ - MULT16_32_Q15(coef1, x[j]);
+ tmp = SHL32(MULT16_32_Q15(coef3, tmp), 2);
scratch[j] = tmp;
}
}
--
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