How to properly detect, decode and play a radio stream?

Question

I am currently trying to write a jukebox-like application in Java that is able to play any audio source possible, but encountered some difficulties when trying to play radio streams.

For playback I use JLayer from JavaZoom, that works fine as long as the target is a direct media file or a direct media stream (I can play PCM, MP3 and OGG just fine). However I encounter difficulties when trying to play radio streams which either contain pre-media data like a m3u/pls file (which I could fix by adding a detection beforehand), or data that is streamed on port 80 while a web-page exists at the same location and the media transmitted depends on the type of request. In the later case, whenever I try to stream the media, I instead get the HTML data.

Example link of a stream that is hidden behind a web-page: http://stream.tn-media.de:8030
This is playable in VLC, but if you put it into a browser or my application you'll receive an HTML file.

Is there:

• A ready-made, free solution that I could use in place of JLayer? Preferably open source so I can study it?
• A tutorial that can help me to write a solution on my own?
• Or can someone give me an example on how to properly detect/request a media stream?

Thanks in advance!

Answer 1

import java.io.*;
import java.net.*;
import javax.sound.sampled.*;
import javax.sound.midi.*;

/**
 * This class plays sounds streaming from a URL: it does not have to preload
 * the entire sound into memory before playing it. It is a command-line
 * application with no gui. It includes code to convert ULAW and ALAW
 * audio formats to PCM so they can be played. Use the -m command-line option
 * before MIDI files.
 */

public class PlaySoundStream {
    // Create a URL from the command-line argument and pass it to the 
    // right static method depending on the presence of the -m (MIDI) option.
    public static void main(String[  ] args) throws Exception {
        if (args[0].equals("-m")) streamMidiSequence(new URL(args[1]));
        else streamSampledAudio(new URL(args[0]));

        // Exit explicitly.
        // This is needed because the audio system starts background threads.
        System.exit(0);
    }

    /** Read sampled audio data from the specified URL and play it */
    public static void streamSampledAudio(URL url)
        throws IOException, UnsupportedAudioFileException,
               LineUnavailableException
    {
        AudioInputStream ain = null;  // We read audio data from here
        SourceDataLine line = null;   // And write it here.

        try {
            // Get an audio input stream from the URL
            ain=AudioSystem.getAudioInputStream(url);

            // Get information about the format of the stream
            AudioFormat format = ain.getFormat( );
            DataLine.Info info=new DataLine.Info(SourceDataLine.class,format);

            // If the format is not supported directly (i.e. if it is not PCM
            // encoded), then try to transcode it to PCM.
            if (!AudioSystem.isLineSupported(info)) {
                // This is the PCM format we want to transcode to.
                // The parameters here are audio format details that you
                // shouldn't need to understand for casual use.
                AudioFormat pcm =
                    new AudioFormat(format.getSampleRate( ), 16,
                                    format.getChannels( ), true, false);

                // Get a wrapper stream around the input stream that does the
                // transcoding for us.
                ain = AudioSystem.getAudioInputStream(pcm, ain);

                // Update the format and info variables for the transcoded data
                format = ain.getFormat( ); 
                info = new DataLine.Info(SourceDataLine.class, format);
            }

            // Open the line through which we'll play the streaming audio.
            line = (SourceDataLine) AudioSystem.getLine(info);
            line.open(format);  

            // Allocate a buffer for reading from the input stream and writing
            // to the line.  Make it large enough to hold 4k audio frames.
            // Note that the SourceDataLine also has its own internal buffer.
            int framesize = format.getFrameSize( );
            byte[  ] buffer = new byte[4 * 1024 * framesize]; // the buffer
            int numbytes = 0;                               // how many bytes

            // We haven't started the line yet.
            boolean started = false;

            for(;;) {  // We'll exit the loop when we reach the end of stream
                // First, read some bytes from the input stream.
                int bytesread=ain.read(buffer,numbytes,buffer.length-numbytes);
                // If there were no more bytes to read, we're done.
                if (bytesread == -1) break;
                numbytes += bytesread;

                // Now that we've got some audio data to write to the line,
                // start the line, so it will play that data as we write it.
                if (!started) {
                    line.start( );
                    started = true;
                }

                // We must write bytes to the line in an integer multiple of
                // the framesize.  So figure out how many bytes we'll write.
                int bytestowrite = (numbytes/framesize)*framesize;

                // Now write the bytes. The line will buffer them and play
                // them. This call will block until all bytes are written.
                line.write(buffer, 0, bytestowrite);

                // If we didn't have an integer multiple of the frame size, 
                // then copy the remaining bytes to the start of the buffer.
                int remaining = numbytes - bytestowrite;
                if (remaining > 0)
                    System.arraycopy(buffer,bytestowrite,buffer,0,remaining);
                numbytes = remaining;
            }

            // Now block until all buffered sound finishes playing.
            line.drain( );
        }
        finally { // Always relinquish the resources we use
            if (line != null) line.close( );
            if (ain != null) ain.close( );
        }
    }

    // A MIDI protocol constant that isn't defined by javax.sound.midi
    public static final int END_OF_TRACK = 47;

    /* MIDI or RMF data from the specified URL and play it */
    public static void streamMidiSequence(URL url)
        throws IOException, InvalidMidiDataException, MidiUnavailableException
    {
        Sequencer sequencer=null;     // Converts a Sequence to MIDI events
        Synthesizer synthesizer=null; // Plays notes in response to MIDI events

        try {
            // Create, open, and connect a Sequencer and Synthesizer
            // They are closed in the finally block at the end of this method.
            sequencer = MidiSystem.getSequencer( );
            sequencer.open( );  
            synthesizer = MidiSystem.getSynthesizer( );
            synthesizer.open( );
            sequencer.getTransmitter( ).setReceiver(synthesizer.getReceiver( ));

            // Specify the InputStream to stream the sequence from
            sequencer.setSequence(url.openStream( ));  

            // This is an arbitrary object used with wait and notify to 
            // prevent the method from returning before the music finishes
            final Object lock = new Object( );

            // Register a listener to make the method exit when the stream is 
            // done. See Object.wait( ) and Object.notify( )
            sequencer.addMetaEventListener(new MetaEventListener( ) {
                    public void meta(MetaMessage e) {
                        if (e.getType( ) == END_OF_TRACK) {
                            synchronized(lock) { 
                                lock.notify( );
                            }
                        }
                    }
                });

            // Start playing the music
            sequencer.start( );

            // Now block until the listener above notifies us that we're done.
            synchronized(lock) {
                while(sequencer.isRunning( )) {
                    try { lock.wait( ); } catch(InterruptedException e) {  }
                }
            }
        }
        finally {
            // Always relinquish the sequencer, so others can use it.
            if (sequencer != null) sequencer.close( );
            if (synthesizer != null) synthesizer.close( );
        }
    }
}

I have used this piece of code in one of my projects that deal with Audio streaming and was working just fine.

Furthermore, you can see similar examples here: Java Audio Example

Answer 2

Just reading the javadoc of AudioSystem give me an idea.

There is an other signature for getAudioInputStream : you can give it an InputStream instead of a URL.

So, try to manage to get the input stream by yourself and add the needed headers so that you get the stream instead the html content:

URLConnection uc = url.openConnection();
uc.setRequestProperty("<header name here>", "<header value here>");

InputStream in = uc.getInputStream();

ain=AudioSystem.getAudioInputStream(in);

Hope this help.

Answer 3

I know this answer comes late, but I had the same issue: I wanted to play MP3 and AAC audio and also wanted the user to insert PLS/M3U links. Here is what I did:
First I tried to parse the type by using the simple file name:

import de.webradio.enumerations.FileExtension;

import java.net.URL;

public class FileExtensionParser {
    /**
     *Parses a file extension
     * @param filenameUrl the url
     * @return the filename. if filename cannot be determined by file extension, Apache Tika parses by live detection
     */
    public FileExtension parseFileExtension(URL filenameUrl) {
        String filename = filenameUrl.toString();
        if (filename.endsWith(".mp3")) {
            return FileExtension.MP3;
        } else if (filename.endsWith(".m3u") || filename.endsWith(".m3u8")) {
            return FileExtension.M3U;
        } else if (filename.endsWith(".aac")) {
            return FileExtension.AAC;
        } else if(filename.endsWith((".pls"))) {
            return FileExtension.PLS;
        }
        URLTypeParser parser = new URLTypeParser();
        return parser.parseByContentDetection(filenameUrl);
    }
}

If that fails, I use Apache Tika to do a kind of live detection:

public class URLTypeParser {


    /** This class uses Apache Tika to parse an URL using her content
     *
     * @param url the webstream url
     * @return the detected file encoding: MP3, AAC or unsupported
     */

    public FileExtension parseByContentDetection(URL url) {
        try {
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            InputStream in = connection.getInputStream();
            BodyContentHandler handler = new BodyContentHandler();
            AudioParser parser = new AudioParser();
            Metadata metadata = new Metadata();
            parser.parse(in, handler, metadata);
            return parseMediaType(metadata);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (TikaException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        }
        return FileExtension.UNSUPPORTED_TYPE;
    }

    private FileExtension parseMediaType(Metadata metadata) {
        String parsedMediaType = metadata.get("encoding");
        if (parsedMediaType.equalsIgnoreCase("aac")) {
            return FileExtension.AAC;
        } else if (parsedMediaType.equalsIgnoreCase("mpeg1l3")) {
            return FileExtension.MP3;
        }
        return FileExtension.UNSUPPORTED_TYPE;
    }

}

This will also solve the HTML problem, since the method will return FileExtension.UNSUPPORTED for HTML content.
I combined this classes together with a factory pattern and it works fine. The live detection takes only about two seconds.

I don't think that this will help you anymore but since I struggled almost three weeks I wanted to provide a working answer. You can see the whole project at github: https://github.com/Seppl2202/webradio