Avalonia.EmbeddedVideoView

Drop-in replacement for LibVLCSharp.Avalonia's VideoView that fixes the native window pop-out issue on Linux.

The Problem

The official LibVLCSharp.Avalonia VideoView creates a separate floating top-level X11 window for video rendering on Linux. This window is positioned to overlap the Avalonia control, but it's not a child of the application window. During layout changes (grid resizing, camera rotation in a multi-view app), the VLC window can:

• Pop out of its grid cell and appear as a separate window
• Show a VLC-labeled window floating over your application
• Appear at incorrect coordinates, especially on 4K displays
• Flash at the stream's native resolution before being repositioned

This is a known limitation of the official library's "airspace" approach and has been discussed extensively in the LibVLCSharp issue tracker.

The Fix

EmbeddedVideoView extends Avalonia's NativeControlHost instead of using a floating window overlay. VLC's rendering surface becomes a child window of the Avalonia host — it physically cannot appear outside its parent bounds.

Official VideoView:
  [Avalonia Window]  ←→  [Floating VLC X11 Window]  ← can pop out!

EmbeddedVideoView:
  [Avalonia Window]
    └── [Child VLC X11 Window]  ← constrained by parent

Usage

1. Add the file

Copy EmbeddedVideoView.cs into your project. It has no dependencies beyond LibVLCSharp and Avalonia (no System.Reactive needed).

2. Update your AXAML

<!-- Before -->
<vlc:VideoView x:Name="VideoView"
               HorizontalAlignment="Stretch"
               VerticalAlignment="Stretch">
    <Border Background="#01000000" ... />
</vlc:VideoView>

<!-- After -->
<local:EmbeddedVideoView x:Name="VideoView"
                          HorizontalAlignment="Stretch"
                          VerticalAlignment="Stretch" />

Remove the transparent Border overlay — it's not needed (and was part of the airspace workaround).

3. Attach your MediaPlayer

VideoView.MediaPlayer = _mediaPlayer;

4. Stretch-to-fill (optional)

If you want the video to stretch to fill the control (ignoring aspect ratio), set AspectRatio in the Playing callback only — not before playback starts:

_mediaPlayer.Playing += (s, e) =>
{
    Dispatcher.UIThread.InvokeAsync(() =>
    {
        if (VideoView.Bounds.Width > 0 && VideoView.Bounds.Height > 0)
            _mediaPlayer.AspectRatio = $"{(int)VideoView.Bounds.Width}:{(int)VideoView.Bounds.Height}";
    });
};

Important: Do NOT pre-set AspectRatio before playback. It causes VLC to create a secondary output window alongside the embedded one.

What you lose

• Click/touch passthrough on video: The official VideoView overlay Border allowed pointer events to bubble through. EmbeddedVideoView doesn't have this — VLC's native window captures input. If you need clickable overlays on video, you'll need a different approach (buttons outside the video cell, or the full unofficial fork with its floating content window).

Tested with

• Avalonia 11.2.2
• LibVLCSharp 3.9.4
• VLC 3.0.22 (system-installed)
• Linux (Debian 13, Wayland + XWayland, GNOME Kiosk)
• 4K display (3840x2160 portrait, scale 1.0)
• 17 concurrent RTSP camera streams
• Intel NUC (i915 GPU, software decode via --avcodec-hw=none)

Credits

Approach based on LibVLCSharp.Avalonia.Unofficial by jpmikkers, which first demonstrated the NativeControlHost approach for Avalonia 11. This version removes the System.Reactive dependency and the floating content overlay, keeping just the embedded rendering.

Built by WINK

This fix was developed for WINK Streaming's camera monitoring platform — a 4K video wall running 17+ concurrent RTSP feeds on Avalonia with LibVLCSharp.

WINK offers enterprise video solutions and custom engineering for video walls, kiosk interfaces, and multi-camera monitoring systems. Get in touch at wink.co.

License

MIT