Fix crash when a frame being deinterleaved has fewer audio channels

than its stream; I'm not sure why this happens but the file that
triggered this commit was stereo AC3 and the crash happened when
(embedded) subtitles were enabled and the file seek was seeked
randomly.  There were frame-sync errors from FFmpeg around the crash.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index c25efa463..c1448ad90 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -225,9 +225,13 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream, uint8_t
 	case AV_SAMPLE_FMT_FLTP:
 	{
 		float** p = reinterpret_cast<float**> (data);
-		for (int i = 0; i < stream->channels(); ++i) {
+		/* Sometimes there aren't as many channels in the _frame as in the stream */
+		for (int i = 0; i < _frame->channels; ++i) {
 			memcpy (audio->data(i), p[i], frames * sizeof(float));
 		}
+		for (int i = _frame->channels; i < stream->channels(); ++i) {
+			audio->make_silent (i);
+		}
 	}
 	break;