A GNOME media player built using GJS with GTK4 toolkit with hardware acceleration. The media player uses GStreamer as a media backend and renders everything via OpenGL.

Scale to fit:

App ID:

Has to be filled


Phone Compatibility:

4 of 5

The player itself is fully adaptive, however the settings window does not quite fit the screen in portrait mode.

How to install:


There is no package in Debian or Mobian yet


sudo flatpak install flathub com.github.rafostar.Clapper



The Clapper-Wiki gives some hints on video acceleration on mobile devices:

V4L2 stateless decoders are gradually added to GStreamer during 1.19 development and are used by default on mobile/embedded devices. Mobile devices usually use GL ES instead of OpenGL, so users should manually tell GStreamer to use it by exporting GST_GL_API=gles2 environment variable.

Due to a bug in GStreamer playbin2 element, GstVideoMeta is not passed through pipeline which causes the v4l2 decoders to copy frames and reduce performance. In order to workaround this bug you can use newer playbin3 element with GST_CLAPPER_USE_PLAYBIN3=1 environment variable.

Other tips include the activation of the (experimental!) vah264dec decoder on Wayland desktops, such as Phosh. You can activate it directly from within clapper. Go to Settings → Advanced → GStreamer and activate the decoder via the Plugin Ranking.

On weaker hardware, like the Pinephone, it might be of benefit to deactivate window shadows via the settings menu in order to boost performance of the video rendering slightly.