From 1647da89dd8ac09a55c111589f7a30d7e6b87d90 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Fri, 18 Jan 2013 13:27:50 -0500
Subject: [PATCH] lavr: make sure that the mix function is reset even if no
 mixing will be done

If the matrix reduction ends up with no mixing matrix needed, we need to still
reset the mix function accordingly and log the info to the user.
---
 libavresample/audio_mix.c | 52 +++++++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 21 deletions(-)

diff --git a/libavresample/audio_mix.c b/libavresample/audio_mix.c
index a3f11b657f..fc37eac6a3 100644
--- a/libavresample/audio_mix.c
+++ b/libavresample/audio_mix.c
@@ -527,28 +527,13 @@ int ff_audio_mix_get_matrix(AudioMix *am, double *matrix, int stride)
     return 0;
 }
 
-int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
+static void reduce_matrix(AudioMix *am, const double *matrix, int stride)
 {
-    int i, o, i0, o0, ret;
-    char in_layout_name[128];
-    char out_layout_name[128];
-
-    if ( am->in_channels <= 0 ||  am->in_channels > AVRESAMPLE_MAX_CHANNELS ||
-        am->out_channels <= 0 || am->out_channels > AVRESAMPLE_MAX_CHANNELS) {
-        av_log(am->avr, AV_LOG_ERROR, "Invalid channel counts\n");
-        return AVERROR(EINVAL);
-    }
-
-    if (am->matrix) {
-        av_free(am->matrix[0]);
-        am->matrix = NULL;
-    }
+    int i, o;
 
     memset(am->output_zero, 0, sizeof(am->output_zero));
     memset(am->input_skip,  0, sizeof(am->input_skip));
-    memset(am->output_skip, 0, sizeof(am->output_zero));
-    am->in_matrix_channels  = am->in_channels;
-    am->out_matrix_channels = am->out_channels;
+    memset(am->output_skip, 0, sizeof(am->output_skip));
 
     /* exclude output channels if they can be zeroed instead of mixed */
     for (o = 0; o < am->out_channels; o++) {
@@ -578,7 +563,7 @@ int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
     }
     if (am->out_matrix_channels == 0) {
         am->in_matrix_channels = 0;
-        return 0;
+        return;
     }
 
     /* skip input channels that contribute fully only to the corresponding
@@ -615,7 +600,7 @@ int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
     }
     if (am->in_matrix_channels == 0) {
         am->out_matrix_channels = 0;
-        return 0;
+        return;
     }
 
     /* skip output channels that only get full contribution from the
@@ -637,8 +622,31 @@ int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
     }
     if (am->out_matrix_channels == 0) {
         am->in_matrix_channels = 0;
-        return 0;
+        return;
     }
+}
+
+int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
+{
+    int i, o, i0, o0, ret;
+    char in_layout_name[128];
+    char out_layout_name[128];
+
+    if ( am->in_channels <= 0 ||  am->in_channels > AVRESAMPLE_MAX_CHANNELS ||
+        am->out_channels <= 0 || am->out_channels > AVRESAMPLE_MAX_CHANNELS) {
+        av_log(am->avr, AV_LOG_ERROR, "Invalid channel counts\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (am->matrix) {
+        av_free(am->matrix[0]);
+        am->matrix = NULL;
+    }
+
+    am->in_matrix_channels  = am->in_channels;
+    am->out_matrix_channels = am->out_channels;
+
+    reduce_matrix(am, matrix, stride);
 
 #define CONVERT_MATRIX(type, expr)                                          \
     am->matrix_## type[0] = av_mallocz(am->out_matrix_channels *            \
@@ -664,6 +672,7 @@ int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
     }                                                                       \
     am->matrix = (void **)am->matrix_## type;
 
+    if (am->in_matrix_channels && am->out_matrix_channels) {
     switch (am->coeff_type) {
     case AV_MIX_COEFF_TYPE_Q8:
         CONVERT_MATRIX(q8, av_clip_int16(lrint(256.0 * v)))
@@ -678,6 +687,7 @@ int ff_audio_mix_set_matrix(AudioMix *am, const double *matrix, int stride)
         av_log(am->avr, AV_LOG_ERROR, "Invalid mix coeff type\n");
         return AVERROR(EINVAL);
     }
+    }
 
     ret = mix_function_init(am);
     if (ret < 0)