Fix crash when FFMpeg doesn't set up the audio channel layout for some reason.

2 files changed, 15 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index fcb18baa1..47f701c29 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2012-09-12  Carl Hetherington  <cth@carlh.net>
+
+	* Fix crash when FFmpeg doesn't set up the audio channel
+	layout for some reason.
+
 2012-09-01  Carl Hetherington  <cth@carlh.net>
 
 	* Add 1.66-within-flat format.
diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index c12e6728d..3471ffaab 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -142,10 +142,18 @@ FFmpegDecoder::setup_audio ()
 	if (_audio_codec == 0) {
 		throw DecodeError ("could not find audio decoder");
 	}
-	
+
 	if (avcodec_open2 (_audio_codec_context, _audio_codec, 0) < 0) {
 		throw DecodeError ("could not open audio decoder");
 	}
+
+	/* This is a hack; sometimes it seems that _audio_codec_context->channel_layout isn't set up,
+	   so bodge it here.  No idea why we should have to do this.
+	*/
+
+	if (_audio_codec_context->channel_layout == 0) {
+		_audio_codec_context->channel_layout = av_get_default_channel_layout (audio_channels ());
+	}
 }
 
 bool
@@ -200,7 +208,7 @@ FFmpegDecoder::audio_channels () const
 	if (_audio_codec_context == 0) {
 		return 0;
 	}
-	
+
 	return _audio_codec_context->channels;
 }