Fix: Library downmixed AAC audios produce whitenoise when played.

MOC asks the FAAD2 library to downmix 5.1 audios to stereo, but MOC
did not adjust the channel count from that of the original audio.

git-svn-id: svn://svn.daper.net/moc/trunk@3003 910807d9-36e0-0310-a014-e9ea483e2ba4

decoder_plugins/aac/aac.c

@@ -249,7 +249,7 @@ static int aac_count_time (struct aac_data *data)
 		return -1;
 
 	samples /= frames;
-	samples /= data->channels;
+	samples /= MIN(2, data->channels);
 	bytes /= frames;
 
 	return ((file_size / bytes) * samples) / data->sample_rate;
@@ -314,7 +314,15 @@ static void *aac_open_internal (struct io_stream *stream, const char *fname)
 		return data;
 	}
 
-	logit ("sample rate %dHz, channels %d", data->sample_rate, data->channels);
+	if (data->channels == 6) {
+		logit ("sample rate %dHz, channels %d (downmixed to stereo)",
+		        data->sample_rate, data->channels);
+		data->channels = 2;
+	}
+	else
+		logit ("sample rate %dHz, channels %d", data->sample_rate,
+		                                        data->channels);
+
 	if (!data->sample_rate || !data->channels) {
 		decoder_error (&data->error, ERROR_FATAL, 0,
 				"Invalid AAC sound parameters");