From 600b4c973fb98f07ec3c5837112865048fb8a607 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Fri, 18 Jan 2013 13:44:10 -0500
Subject: [PATCH] lavr: fix matrix reduction for upmixing in certain cases
Do not skip an output if the corresponding input contributes to other output
channels.
---
libavresample/audio_mix.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/libavresample/audio_mix.c b/libavresample/audio_mix.c
index 096bcf3d660..487bddf7465 100644
--- a/libavresample/audio_mix.c
+++ b/libavresample/audio_mix.c
@@ -607,6 +607,7 @@ static void reduce_matrix(AudioMix *am, const double *matrix, int stride)
corresponding input channel */
for (o = 0; o < FFMIN(am->in_channels, am->out_channels); o++) {
int skip = 1;
+ int o0;
for (i = 0; i < am->in_channels; i++) {
if ((o != i && matrix[o * stride + i] != 0.0) ||
@@ -615,6 +616,15 @@ static void reduce_matrix(AudioMix *am, const double *matrix, int stride)
break;
}
}
+ /* check if the corresponding input channel makes a contribution to
+ any other output channel */
+ i = o;
+ for (o0 = 0; o0 < am->out_channels; o0++) {
+ if (o0 != i && matrix[o0 * stride + i] != 0.0) {
+ skip = 0;
+ break;
+ }
+ }
if (skip) {
am->output_skip[o] = 1;
am->out_matrix_channels--;
--
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