Playing Audio

WARNING

Support for audio was added to Javacord very recently. If you encounter any bugs, please create an issue on GitHub!

Javacord allows your bot to connect to voice channels and play audio (e.g., music). This short tutorial gives you an introduction on how to connect to a voice channel and play your favorite music.

🔌 Connect to a voice channel

Connecting to a voice channel is very straight forward: Calling #connect() on an instance of ServerVoiceChannel will connect your bot to this voice channel and return a future with an AudioConnection object.

Example

The following example will connect the bot to the voice channel of the user that typed !music in the chat:

ServerVoiceChannel channel = ...;
channel.connect().thenAccept(audioConnection -> {
    // Do stuff
}).exceptionally(e -> {
    // Failed to connect to voice channel (no permissions?)
    e.printStackTrace();
    return null;
});

👂 Playing music

There are plenty of sources for audio (e.g., YouTube, local files, etc.). The current de facto standard library for extracting audio from these sources with Java is the LavaPlayer library.

To use it with Javacord, you have to add it as a dependency to your project (e.g., with Gradle or Maven) and create a Javacord audio source like this:

public class LavaplayerAudioSource extends AudioSourceBase {

    private final AudioPlayer audioPlayer;
    private AudioFrame lastFrame;

    /**
     * Creates a new lavaplayer audio source.
     *
     * @param api A discord api instance.
     * @param audioPlayer An audio player from Lavaplayer.
     */
    public LavaplayerAudioSource(DiscordApi api, AudioPlayer audioPlayer) {
        super(api);
        this.audioPlayer = audioPlayer;
    }

    @Override
    public byte[] getNextFrame() {
        if (lastFrame == null) {
            return null;
        }
        return applyTransformers(lastFrame.getData());
    }

    @Override
    public boolean hasFinished() {
        return false;
    }

    @Override
    public boolean hasNextFrame() {
        lastFrame = audioPlayer.provide();
        return lastFrame != null;
    }

    @Override
    public AudioSource copy() {
        return new LavaplayerAudioSource(getApi(), audioPlayer);
    }
}

With this audio source, you can now start using Lavaplayer, e.g. to play a YouTube video:

// Create a player manager
AudioPlayerManager playerManager = new DefaultAudioPlayerManager();
playerManager.registerSourceManager(new YoutubeAudioSourceManager());
AudioPlayer player = playerManager.createPlayer();

// Create an audio source and add it to the audio connection's queue
AudioSource source = new LavaplayerAudioSource(api, player);
audioConnection.setAudioSource(source);

// You can now use the AudioPlayer like you would normally do with Lavaplayer, e.g.,
playerManager.loadItem("https://www.youtube.com/watch?v=NvS351QKFV4", new AudioLoadResultHandler() {
    @Override
    public void trackLoaded(AudioTrack track) {
        player.playTrack(track);
    }

    @Override
    public void playlistLoaded(AudioPlaylist playlist) {
        for (AudioTrack track : playlist.getTracks()) {
            player.playTrack(track);
        }
    }

    @Override
    public void noMatches() {
        // Notify the user that we've got nothing
    }

    @Override
    public void loadFailed(FriendlyException throwable) {
        // Notify the user that everything exploded
    }
});