Intel QSV Gen12

Intel QSV transcode on Gen12+ iGPUs needs the oneVPL GPU runtime

Symptom

On a Gen12+ Intel iGPU (Alder Lake / N-series; e.g. the N97, iHD driver 23.x) every QSV transcode fails immediately. HandBrake selects the QSV encoder, reaches encoder init, then dies:

[…] encavcodecInit: H.264 (Intel Quick Sync Video)
[QSV @ …] Error setting child device handle: -17
ERROR: hwaccel: failed to create hwdevice
ERROR: Failure to initialise thread 'FFMPEG encoder (libavcodec)'
[…] libhb: work result = 3
Encode failed (error 3).

The task ends rc=3. Today this is caught before it ever reaches a real job: the backend's per-device probe test-encodes with QSV before advertising the row as eligible, so a Gen12+ device stuck this way simply verifies nothing and an any_h265-style preset runs on CPU from the start, rather than a job failing mid-transcode and falling back. On small fanless Intel boxes a CPU software encode can still peg all cores for hours, so the fix below is worth applying either way.

Root cause

The transcode image shipped the oneVPL dispatcher (libvpl2) and the legacy Intel Media SDK GPU runtime (libmfxhw64.so), but not the modern oneVPL GPU runtime (libmfx-gen). On Gen12+ silicon the legacy Media SDK is deprecated/unsupported, so oneVPL falls back to it and fails with the -17 child-device-handle error.

It is not a device or permission problem: the render node is passed into the container, the iHD driver loads, and vainfo reports VAProfileH264High : VAEntrypointEncSlice (VA-API h264 encode is available). The sole missing piece is the GPU-side oneVPL runtime package.

Fix

Install libmfx-gen1.2 (Intel oneVPL GPU Runtime) alongside libvpl2 in the transcode image (services/transcode/Dockerfile). With it present, oneVPL dispatches to the modern runtime and QSV hardware encode succeeds.

Verification

On an Intel N97, after adding the package, HandBrakeCLI … -e qsv_h264 produces encavcodecInit: H.264 (Intel Quick Sync Video) → libhb: work result = 0 → Encode done! with output written, and a full rip→transcode→completed run lands the finished .mkv in the media root. No -17, no rc=3, no CPU fallback.