Fixed mp3 playback on linux and added support for mono mp3s

src/modules/sound/lullaby/Mpg123Decoder.cpp

@@ -34,7 +34,7 @@ namespace lullaby
 	bool Mpg123Decoder::inited = false;
 
 	Mpg123Decoder::Mpg123Decoder(Data * data, const std::string & ext, int bufferSize, int sampleRate)
-		: Decoder(data, ext, bufferSize, sampleRate), handle(0)
+		: Decoder(data, ext, bufferSize, sampleRate), channels(MPG123_STEREO), handle(0)
 	{
 
 		data_size = data->getSize();
@@ -57,9 +57,6 @@ namespace lullaby
 		ret = mpg123_open_feed(handle);
 		if (ret != MPG123_OK)
 			throw love::Exception("Could not open feed.");
-		ret = mpg123_format(handle, sampleRate, MPG123_STEREO, MPG123_ENC_SIGNED_16);
-		if (ret != MPG123_OK)
-			throw love::Exception("Could not set output format.");
 
 		ret = feed(16384);
 
@@ -113,6 +110,20 @@ namespace lullaby
 			switch(r)
 			{
 			case MPG123_NEW_FORMAT:
+				{
+					long rate = 0;
+					int encoding = 0;
+					int ret = mpg123_getformat(handle, &rate, &channels, &encoding);
+					if (rate == 0)
+						rate = sampleRate;
+					if (channels == 0)
+						channels = MPG123_STEREO;
+					if (encoding == 0)
+						encoding = MPG123_ENC_SIGNED_16;
+					ret = mpg123_format(handle, rate, channels, encoding);
+					if (ret != MPG123_OK)
+						throw love::Exception("Could not set output format.");
+				}
 				continue;
 			case MPG123_NEED_MORE:
 				{
@@ -186,7 +197,7 @@ namespace lullaby
 
 	int Mpg123Decoder::getChannels() const
 	{
-		return 2;
+		return channels;
 	}
 
 	int Mpg123Decoder::getBits() const

src/modules/sound/lullaby/Mpg123Decoder.h

@@ -48,6 +48,8 @@ namespace lullaby
 		int data_offset;
 		int data_size;
 
+		int channels;
+
 	public:
 
 		Mpg123Decoder(Data * data, const std::string & ext, int bufferSize, int sampleRate);