Creating an ExoPlayer with your own audioprocessor

MainActivity.kt

private val fftAudioProcessor = FFTAudioProcessor()

val renderersFactory = object : DefaultRenderersFactory(this) {
    override fun buildAudioProcessors(): Array<AudioProcessor> {
        val processors = super.buildAudioProcessors()
        return processors + fftAudioProcessor
    }
}
player = ExoPlayerFactory.newSimpleInstance(this, renderersFactory, DefaultTrackSelector())