bitstream = new Bitstream(file.read());
decoder = new MP3Decoder();
try {
Header header = bitstream.readFrame();
if (header == null) throw new GdxRuntimeException("empty ogg");
int channels = header.mode() == Header.SINGLE_CHANNEL ? 1 : 2;
outputBuffer = new OutputBuffer(channels, false);
decoder.setOutputBuffer(outputBuffer);
setup(channels, header.getSampleRate());
} catch (BitstreamException e) {
throw new GdxRuntimeException("error while preloading mp3", e);