Hardware-accelerated video playback

2026-10-04 - Hardware-accelerated video playback

The kernel now supports the hardware JPEG/MJPEG decoder (JDEC) and scaler (SCL) as standard V4L2 memory-to-memory drivers. The decoder outputs NV12 or XBGR32, and the scaler takes either one and resizes it up or down into XBGR32. Both fully pass the v4l2-compliance test suite.
A new zero-copy fullscreen video player for MJPEG AVI files, wmt-play, is included on new desktop images. Frames are handed from the decoder to the scaler to the display as dma-bufs, and shown with vblank-timed page flips on a display leased from X. It handles up to 720p at 30 frames per second or 480p at 60, with pause, seeking, frame stepping, and looping. To add it to an existing install, run sudo apt install wmt-play after upgrading.
Videos are converted for the player on another computer with ffmpeg, using the wmt-encode.sh script in the wmt-play repository, which scales larger video down to fit the panel and writes MJPEG with 16-bit PCM audio.
The X.org driver now supports RandR 1.6 leasing, which hands the display to a single program and takes it back when that program exits or dies.
A new ALSA front device gives a program exclusive control of the sound card while maintaining the default device's left/right channel swap, and passes through the stream pause support now in the audio driver. Mono playback now reaches both channels.
The graphics driver now signals vertical blanking from the pre-vblank interrupt, so page-flip events reach a program early in the blanking interval.
The package builder now handles recipes that carry their own Debian packaging, and builds the X.org driver and the player from their release tags. The X.org driver's packaging moved there from its own repository.
Kernel updated to 6.12.112.
Refreshed standard and desktop images.