Hardware acceleration

Using hardware acceleration is highly recommended. As stated in GStreamer wiki:

In the case of OpenGL based elements, the buffers have the GstVideoGLTextureUploadMeta meta, which
efficiently copies the content of the VA-API surface into a GL texture.

Clapper uses OpenGL based sinks, so when VA-API is available, both CPU and RAM usage is much lower. Especially with gst-plugins-bad 1.18+ and new vah264dec decoder which shares a single GL context with Clapper and uses DRM connection. If you have an AMD/Intel GPU and use Wayland session, I highly recommend enabling this new decoder in Clapper Preferences->Advanced->GStreamer.

On some GPUs you might need to export GST_VAAPI_ALL_DRIVERS=1 environment variable.

Other acceleration methods (supported by GStreamer) should also work, but I have not tested them due to lack of hardware.