VLCJ Interview Questions
1. What is vlcj?
VLCJ is a Java framework/API that provides bindings to LibVLC, allowing Java applications to natively control the VLC media player.
2. What are some key components of vlcj?
Some key components are the MediaPlayer, Media, EmbeddedMediaPlayer and Canvas components. These allow you to play media, control playback, handle events and display video output.
3. How do you play a video file using vlcj?
You create a Media object with the video URI, create a MediaPlayer instance, call mediaPlayer.play(media) and attach the media player to a Canvas to display the video.
4. How is audio handled in vlcj?
You can get audio samples using vlcj’s AudioOutput component. The audio samples can be played using JavaSound APIs like SourceDataLine.
5. What are some important vlcj events?
Some key events are MediaPlayerEvent.Playing, MediaPlayerEvent.Paused, MediaPlayerEvent.Stopped, MediaPlayerEvent.EndReached. These allow you to monitor the media playback status.
6. How do you handle errors in vlcj?
You can listen for MediaPlayerEvent.Error events. The MediaPlayerException contains the error code and message to help identify issues.
7. What threading models does vlcj support?
Vlcj supports executing media operations on the main UI thread or a dedicated media handler thread. The latter prevents blocking the UI thread.
8. How do you enable and handle user interaction in vlcj?
You can use call mediaPlayer.enableKeyInput() and listen for KeyEvent to handle key presses. The EmbeddedMediaPlayer can also show native UI like playback controls.
9. What dependencies are required to use vlcj?
You need the JRE, vlcj.jar, the LibVLC native libraries (.dll, .so, .dylib) appropriate for the platform and the VLC application if showing video output.
10. How does vlcj integrate with VLC?
Vlcj uses Java Native Interface (JNI) to interface with the native LibVLC library. The vlcj jar contains JNI code to call LibVLC functions.