From 5ab07e6b9a349c5e612890236cd1a5fd06c6b9fc Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Sat, 3 Nov 2012 11:36:39 -0400
Subject: [PATCH] comb_filter() bypass for the case where the gain is zero.
---
celt/celt.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/celt/celt.c b/celt/celt.c
index c68566f0f..26695fae8 100644
--- a/celt/celt.c
+++ b/celt/celt.c
@@ -639,6 +639,14 @@ static void comb_filter(opus_val32 *y, opus_val32 *x, int T0, int T1, int N,
{QCONST16(0.3066406250f, 15), QCONST16(0.2170410156f, 15), QCONST16(0.1296386719f, 15)},
{QCONST16(0.4638671875f, 15), QCONST16(0.2680664062f, 15), QCONST16(0.f, 15)},
{QCONST16(0.7998046875f, 15), QCONST16(0.1000976562f, 15), QCONST16(0.f, 15)}};
+
+ if (g0==0 && g1==0)
+ {
+ /* OPT: Happens to work without the OPUS_MOVE(), but only because the current encoder already copies x to y */
+ if (x!=y)
+ OPUS_MOVE(y, x, N);
+ return;
+ }
g00 = MULT16_16_Q15(g0, gains[tapset0][0]);
g01 = MULT16_16_Q15(g0, gains[tapset0][1]);
g02 = MULT16_16_Q15(g0, gains[tapset0][2]);
@@ -667,6 +675,13 @@ static void comb_filter(opus_val32 *y, opus_val32 *x, int T0, int T1, int N,
x1=x0;
}
+ if (g1==0)
+ {
+ /* OPT: Happens to work without the OPUS_MOVE(), but only because the current encoder already copies x to y */
+ if (x!=y)
+ OPUS_MOVE(y+overlap, x+overlap, N-overlap);
+ return;
+ }
/* OPT: For machines where the movs are costly, unroll by 5 */
for (;i<N;i++)
{
--
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