Java doesn’t support .mp3 format, so I tried to use JLayer library to play mp3 audio. But the Player of JLayer doesn’t support play-time volume control and pause.

So I’m finding a better way to play mp3 audio on Desktop, with Compose Multiplatform.

The input mp3 audio will be given as a ByteArray. It should support these features.

• pause and play
• play-time volume control
• conditional audio loop

expect class AudioManager constructor(data: ByteArray) {
    var volume: Float

    var loop: Boolean

    fun play()

    fun pause()

    fun stop()
}

This is the expect class of my AudioManager.

actual class AudioManager actual constructor(data: ByteArray) {

    private val mediaPlayer = MediaPlayer().apply {
        val mediaSource = ByteArrayMediaDataSource(data)
        setDataSource(mediaSource)
        prepare()
    }

    actual var volume: Float = 1F
        set(value) {
            mediaPlayer.setVolume(value, value)
            field = value
        }

    actual var loop: Boolean = false
        set(value) {
            mediaPlayer.isLooping = value
            field = value
        }

    actual fun play() {
        mediaPlayer.start()
    }

    actual fun pause() {
        mediaPlayer.pause()
    }

    actual fun stop() {
        mediaPlayer.stop()
    }

    inner class ByteArrayMediaDataSource(private val data: ByteArray) : MediaDataSource() {

        override fun readAt(position: Long, buffer: ByteArray, offset: Int, size: Int): Int {
            System.arraycopy(data, position.toInt(), buffer, offset, size)
            return size
        }

        override fun getSize(): Long {
            return data.size.toLong()
        }

        override fun close() { }
    }
}

And this is sample code for Android target using MediaPlayer that I’ve written.