The Linux host was NVENC/CUDA-only. Add a VAAPI encoder — one libavcodec
backend (h264/hevc/av1_vaapi) covering both AMD (Mesa radeonsi) and Intel
(iHD) — behind the existing `Encoder` trait, and turn `open_video`'s Linux
arm into a vendor dispatcher: `PUNKTFUNK_ENCODER=auto|nvenc|vaapi` (default
auto: NVENC when a CUDA frame or /dev/nvidia* is present, else VAAPI). The
NVIDIA path is unchanged — auto resolves to NVENC on an NVIDIA box and the
bitrate-probe loop moved verbatim into `open_nvenc_probed`.
`VaapiEncoder` mirrors the NVENC hwframes pattern with AV_HWDEVICE_TYPE_VAAPI.
The CPU-input path swscales packed RGB -> NV12 (BT.709 limited, VUI signalled)
and uploads into a pooled VA surface (av_hwframe_transfer_data), preserving the
low-latency model (infinite GOP, on-demand forced IDR, async_depth=1, CBR when
the driver supports it). It works on a non-NVIDIA box with no capture changes:
the capturer already falls back to CPU frames when its EGL->CUDA importer can't
initialise (no libcuda).
Live-validated on a Radeon 780M (RDNA3): hevc/h264/av1_vaapi all encode,
HEVC/H264 decode cleanly with correct BT.709-limited colours, infinite GOP
preserved. Zero-copy dmabuf import (the high-res perf lever) is next.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
enricobuehler
2823785bb6