反复播放同一视频几个小时后，JavaFX 视频卡顿

Question

On Ubuntu 18.04 I have a JavaFX 13 app that plays the same video over and over using javafx.scene.media.MediaPlayer and javafx.scene.media.MediaView. In each iteration it loads the MediaPlayer with same media via url and then plays it. At first the video plays smoothly but after about an hour it starts stuttering in my machine with 8GB of RAM and does not happen (at least in a few hours) in my machine with 32GB of RAM.

Since its plays smooth initially I am guessing its not a codec issue. Since it gets worse with time I am guessing its a memory leak somewhere. Monitoring my JVM using visualvm it does not appear to be a memory or thread leak in my app.

Below is a stripped down version of my app in a single java class file. Any tips would be greatly appreciated.

package javafxtest;

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.scene.media.Media;
import javafx.scene.media.MediaPlayer;
import javafx.scene.media.MediaView;
import javafx.stage.Stage;
import javafx.util.Duration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;

public class JavaFxVideoTestApp extends Application {
    private static final Logger LOGGER = LoggerFactory.getLogger(JavaFxVideoTestApp.class);

    MediaPlayer mediaPlayer;
    MediaView mediaView;

    public static void main(String[] args) {
        Application.launch(args);
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        Thread.setDefaultUncaughtExceptionHandler(JavaFxVideoTestApp::showError);

        BorderPane borderPane = new BorderPane();
        Scene scene = new Scene(borderPane);
        primaryStage.setScene(scene);

        mediaView = new MediaView();
        borderPane.setCenter(mediaView);

        primaryStage.setFullScreen(true);
        primaryStage.show();

        loadEvent();
    }

    private static void showError(Thread thread, Throwable throwable) {
        LOGGER.error("Unhandled error. Thread: {}", thread.getName(), throwable);
    }

    public void loadEvent() throws MalformedURLException, URISyntaxException {
        String videoFileURI = (new URL("https://dl.dropboxusercontent.com/s/b8lyrt5r61oxxnc/job-chasing-his-illusive-dreams-dec-2017.mp4")).toURI().toString();

        // Create a new MediaPlayer
        resetMediaPlayer("loadEvent");

        Media media = new Media(videoFileURI);
        LOGGER.debug("LoadEvent new video loaded : {}", media.getSource());
        mediaPlayer = new MediaPlayer(media);
        mediaPlayer.setStartTime(Duration.ZERO);
        mediaPlayer.errorProperty().addListener((observable, oldValue, newValue) ->
                LOGGER.error(String.format("MediaPlayer error. videoFileURI: %s error: '%s'", videoFileURI, newValue)));
        mediaPlayer.statusProperty().addListener((observable, oldValue, newValue) -> {
            if (newValue == MediaPlayer.Status.READY) {
                LOGGER.info("MediaPlayer status: Ready");
                showEvent();
            }
        });
        mediaPlayer.setCycleCount(1);
        mediaPlayer.setMute(true);
        mediaPlayer.setOnEndOfMedia(() -> {
            try {
                loadEvent();
            } catch (MalformedURLException|URISyntaxException e) {
                LOGGER.error("Error loading event", e);
            }
        });
        mediaView.setMediaPlayer(mediaPlayer);
    }

    public void showEvent() {
        if (mediaPlayer != null) {
            MediaPlayer.Status status = mediaPlayer.getStatus();
            if (status == MediaPlayer.Status.READY || status == MediaPlayer.Status.STOPPED) {
                mediaPlayer.setStartTime(Duration.ZERO);
                mediaPlayer.setStopTime(mediaPlayer.getMedia().getDuration());
                mediaPlayer.setCycleCount(MediaPlayer.INDEFINITE);
                mediaPlayer.play();
            }
        } else {
            LOGGER.error("showEvent video mediaplayer NULL");
        }
    }

    private void resetMediaPlayer(String caller) {
        if (mediaPlayer != null) {
            LOGGER.debug("resetMediaPlayer stop. caller: {}", caller);
            if ((mediaPlayer.getStatus() != MediaPlayer.Status.UNKNOWN) && (mediaPlayer.getStatus() != MediaPlayer.Status.DISPOSED)) {
                try {
                    mediaPlayer.stop();
                    mediaPlayer.dispose();
                    mediaPlayer = null;
                } catch (Exception e) {
                    LOGGER.error("Error while stopping and disposing media player");
                }
            }
        }
    }
}

Answer 1

This seems to be a issue of the cycelingprocess and allocation of the Mediaplayer's Memory. I had a similar issue, sady I don't know why this happens, but I have a Workarround, to imitate a cycle.

My workarround is this:

    public void startPlayer(){
        mediaPlayer = new MediaPlayer(media);
        mediaView.setMediaPlayer(mediaPlayer);
        mediaPlayer.play();

        mediaPlayer.setOnEndOfMedia(()->{
                    //frees all the allocated Memory
                    mediaPlayer.dispose();
                    mediaView.setMediaPlayer(null);
                    startPlayer();
                });
    }

This will create a new Player each time the cycle has ended.

I don't know if this will work for you in the aspect of smoothness of the "Video cycle". But you can give it a try. Maybe you can to this after every 10 video cycles or so, to obtain smoothness.

Answer 2

mediaPlayer.setOnEndOfMedia(() -> {
            try {
                mediaPlayer.stop();
                mediaPlayer.dispose();
                mediaPlayer = null;
                loadEvent(); ...

Answer 3

I have tried running my app with gstreamer 1.16.2. Since no backports for it was available for Ubuntu 18.04 I ran my app in a VM with Ubuntu 20 (latest nightly) which has gstreamer 1.16.2-2. The VM has 4GB ram and 1 cpu. This is lesser resources than my original test machine.

With gstreamer 1.16.2-2 in Ubuntu 20 I am not seeing a stutter after running my test for 1.25 hours. To me this confirms that problem is in gstream 1.14 and fixed in gstreamer 1.16. Thanks to all who tried to help.

UPDATE: Above was based on testing in an Ubuntu 20.04 VM. I then upgraded my physical test machine to Ubuntu 20.04.

Much to my surprise the video stutter showed in my app immediately (not even waiting for 30 minutes as before). Reading up on it I found that some gnome shell extensions can cause video stutter. So I removed the following gnome shell extension:

# See what gnome shell extensions are installed
apt list --installed | grep -i extension

# Remove gnome shell extensions found
sudo apt-get remove gnome-shell-extension-appindicator gnome-shell-extension-desktop-icons gnome-shell-extension-ubuntu-dock

After that I restarted my app and the video stutter was gone. I then waited 30 minutes to see if stutter appeared like before. The stutter is noticeable unfortunately. I have unmarked this answer as an accepted answer.