From 70c275f8c335f9f8846af5cce65fef29247759b2 Mon Sep 17 00:00:00 2001
From: Stefano Sabatini <stefano.sabatini-lala@poste.it>
Date: Sun, 13 Feb 2011 22:59:55 +0100
Subject: [PATCH] Make avfilter_config_links() propagate audio information of
 the source link if it is not explicitely set by the filter.

---
 libavfilter/avfilter.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c
index 872ca2384f..4d183294cb 100644
--- a/libavfilter/avfilter.c
+++ b/libavfilter/avfilter.c
@@ -198,6 +198,12 @@ int avfilter_config_links(AVFilterContext *filter)
                 link->sample_aspect_ratio = link->src->input_count ?
                     link->src->inputs[0]->sample_aspect_ratio : (AVRational){1,1};
 
+            if (link->sample_rate == 0 && link->src && link->src->input_count)
+                link->sample_rate = link->src->inputs[0]->sample_rate;
+
+            if (link->channel_layout == 0 && link->src && link->src->input_count)
+                link->channel_layout = link->src->inputs[0]->channel_layout;
+
             if ((config_link = link->dstpad->config_props))
                 if ((ret = config_link(link)) < 0)
                     return ret;