The code below triggers on changes to the enabledTracks variable and attempts to remove AudioTracks. It doesn't work because this variable is always empty.

package javafxmedia;

import javafx.scene.media.AudioTrack;
import javafx.scene.media.Media;
import javafx.scene.media.MediaPlayer;
import javafx.scene.media.MediaView;
import javafx.scene.Scene;
import javafx.stage.Stage;

var mediaURL = "http://sun.edgeboss.net/download/sun/media/1460825906/"
               "1460825906_2956241001_big-buck-bunny-640x360.flv";

var media = Media { source: mediaURL };
var mediaPlayer: MediaPlayer;
var enabledTracks = bind mediaPlayer.enabledTracks with inverse on replace {
    for (track in enabledTracks) {
        if (track instanceof AudioTrack) {
            delete track from enabledTracks;
        }
    }
}

Stage {
    title: "Media #8"
    resizable: false
    scene: Scene {
        width: 640
        height: 400
        content: [
            MediaView {
                mediaPlayer:
                mediaPlayer = MediaPlayer {
                    autoPlay: true
                    media: media
                }
            }
        ]
    }
}