From 0b60fc94aab63b80b3a898c744da50758215bc9c Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Thu, 10 Jan 2013 00:27:04 +0100
Subject: [PATCH] swr: reorder the operations in the noise shaping code
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
libswresample/dither.c | 1 +
libswresample/dither_template.c | 5 +++--
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/libswresample/dither.c b/libswresample/dither.c
index c3bb5609ed9..66bf1843104 100644
--- a/libswresample/dither.c
+++ b/libswresample/dither.c
@@ -118,6 +118,7 @@ int swri_dither_init(SwrContext *s, enum AVSampleFormat out_fmt, enum AVSampleFo
if (s->dither.method > SWR_DITHER_NS) {
s->dither.noise.bps = 4;
s->dither.noise.fmt = AV_SAMPLE_FMT_FLTP;
+ s->dither.noise_scale = 1;
}
return 0;
diff --git a/libswresample/dither_template.c b/libswresample/dither_template.c
index ffa5bdd664c..3388aadc56e 100644
--- a/libswresample/dither_template.c
+++ b/libswresample/dither_template.c
@@ -34,12 +34,13 @@ void RENAME(swri_noise_shaping)(SwrContext *s, AudioData *srcs, AudioData *noise
DELEM *data = (DELEM*)srcs->ch[ch];
pos = s->dither.ns_pos;
for (i=0; i<count; i++) {
- double d1, d = data[i];
+ double d1, d = data[i]*S_1;
for(j=0; j<taps; j++)
d -= s->dither.ns_coeffs[j] * s->dither.ns_errors[ch][pos + j];
pos = pos ? pos - 1 : pos - 1 + taps;
- d1 = rint((d + noise[i]) * S_1)*S;
+ d1 = rint(d + noise[i]);
s->dither.ns_errors[ch][pos + taps] = s->dither.ns_errors[ch][pos] = d1 - d;
+ d1 *= S;
CLIP(d1);
data[i] = d1;
}
--
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