fix a few bugs in mp3_decode and minimize alsa underruns by playing silence when switch songs

src/audio.c

@@ -278,6 +278,11 @@ int playAudio(char * playChunk, int size) {
 	return 0;
 }
 
+int isAudioDeviceOpen() {
+	if(audio_device) return 1;
+	return 0;
+}
+
 void closeAudioDevice() {
 #ifdef HAVE_AUDIO
 	if(audio_device) {

src/audio.h

@@ -49,6 +49,8 @@ int playAudio(char * playChunk,int size);
 
 void closeAudioDevice();
 
+int isAudioDeviceOpen();
+
 void audioError();
 
 int isCurrentAudioFormat(AudioFormat * audioFormat);

src/decode.c

@@ -98,6 +98,12 @@ int calculateCrossFadeChunks(PlayerControl * pc, AudioFormat * af) {
 	return (int)chunks;
 }
 
+#define playSilenceOrSleep() \
+	if(isAudioDeviceOpen()) { \
+		playAudio(silence, CHUNK_SIZE); \
+	} \
+	else my_usleep(10000);
+
 #define handleDecodeStart() \
         if(decodeWaitedOn) { \
                 if(dc->state!=DECODE_STATE_START &&  *decode_pid > 0 && \
@@ -128,7 +134,7 @@ int calculateCrossFadeChunks(PlayerControl * pc, AudioFormat * af) {
 		        return; \
                 } \
                 else { \
-                        my_usleep(10000); \
+			my_usleep(10000); \
                         continue; \
                 } \
         }
@@ -462,9 +468,8 @@ void decodeParent(PlayerControl * pc, DecoderControl * dc, OutputBuffer * cb) {
 				dc->state!=DECODE_STATE_STOP) 
 	{
 		processDecodeInput();
-                handleDecodeStart();
 		if(quit) return;
-		my_usleep(10000);
+		playSilenceOrSleep();
 	}
 
 	while(!quit) {

src/inputPlugins/mp3_plugin.c

@@ -575,12 +575,12 @@ int mp3Read(mp3DecodeData * data, OutputBuffer * cb, DecoderControl * dc) {
                                                 MP3_DATA_OUTPUT_BUFFER_SIZE,
                                                 data->elapsedTime,
                                                 data->bitRate/1000);
+                                data->outputPtr = data->outputBuffer;
+
                                 if(ret == OUTPUT_BUFFER_DC_STOP) {
                                         return DECODE_BREAK;
                                 }
 
-                                data->outputPtr = data->outputBuffer;
-
                                 if(ret == OUTPUT_BUFFER_DC_SEEK) break;
 			}
 		}
@@ -640,7 +640,7 @@ void initAudioFormatFromMp3DecodeData(mp3DecodeData * data, AudioFormat * af) {
 
 int mp3_decode(OutputBuffer * cb, DecoderControl * dc, InputStream * inStream) {
 	mp3DecodeData data;
-	MpdTag * tag;
+	MpdTag * tag = NULL;
 
 	if(openMp3FromInputStream(inStream, &data, dc, &tag) < 0) {
 		closeInputStream(inStream);
@@ -664,7 +664,6 @@ int mp3_decode(OutputBuffer * cb, DecoderControl * dc, InputStream * inStream) {
 		if(tag) freeMpdTag(tag);
 		tag = newMpdTag();
 		tag->title = strdup(inStream->metaTitle);
-		/* free ths now, so we know we are done with it */
 		free(inStream->metaTitle);
 		inStream->metaTitle = NULL;
 		if(inStream->metaName) {
@@ -694,7 +693,7 @@ int mp3_decode(OutputBuffer * cb, DecoderControl * dc, InputStream * inStream) {
 
 	while(mp3Read(&data,cb,dc)!=DECODE_BREAK);
 	/* send last little bit if not dc->stop */
-	if(data.outputPtr!=data.outputBuffer && data.flush)  {
+	if(!dc->stop && data.outputPtr!=data.outputBuffer && data.flush)  {
         	sendDataToOutputBuffer(cb, NULL, dc, 
                                 data.inStream->seekable,
                                 data.outputBuffer,

src/inputPlugins/ogg_plugin.c

@@ -321,9 +321,8 @@ int ogg_decode(OutputBuffer * cb, DecoderControl * dc, InputStream * inStream)
 						ov_pcm_tell(&vf)/
 						dc->audioFormat.sampleRate,
 						bitRate);
-					
-			if(dc->stop) break;
 			chunkpos = 0;
+			if(dc->stop) break;
 		}
 	}