Decode Mp3 File to byte Array for Audio Manipulation or play with AudioTrack - Android Studio.

Mp3Decoder

public static byte[] decode(String path, int startMs, int maxMs) 
		throws IOException, com.mindtherobot.libs.mpg.DecoderException {
		ByteArrayOutputStream outStream = new ByteArrayOutputStream(1024);
		
		float totalMs = 0;
		boolean seeking = true;
		
		File file = new File(path);
		InputStream inputStream = new BufferedInputStream(new FileInputStream(file), 8 * 1024);
		try {
			Bitstream bitstream = new Bitstream(inputStream);
			Decoder decoder = new Decoder();
			
			boolean done = false;
			while (! done) {
				Header frameHeader = bitstream.readFrame();
				if (frameHeader == null) {
					done = true;
				} else {
					totalMs += frameHeader.ms_per_frame();

					if (totalMs >= startMs) {
						seeking = false;
					}
					
					if (! seeking) {
						SampleBuffer output = (SampleBuffer) decoder.decodeFrame(frameHeader, bitstream);
						
						if (output.getSampleFrequency() != 44100
								|| output.getChannelCount() != 2) {
							throw new com.mindtherobot.libs.mpg.DecoderException("mono or non-44100 MP3 not supported");
						}
						
						short[] pcm = output.getBuffer();
						for (short s : pcm) {
							outStream.write(s & 0xff);
							outStream.write((s >> 8 ) & 0xff);
						}
					}
					
					if (totalMs >= (startMs + maxMs)) {
						done = true;
					}
				}
				bitstream.closeFrame();
			}
			
			return outStream.toByteArray();
		} catch (BitstreamException e) {
			throw new IOException("Bitstream error: " + e);
		} catch (DecoderException e) {
			Log.w(TAG, "Decoder error", e);
			throw new com.mindtherobot.libs.mpg.DecoderException(e);
		} finally {
			IOUtils.safeClose(inputStream);			
		}
	}