Adds a brute-force fallback to v4l2request_open_decoder() that
enumerates /dev/media[0..15] and /dev/video[0..63] directly when
udev_enumerate_scan_devices() returns an error. The fallback uses
absolute paths only (no fd-relative openat), which is what makes it
work inside firefox's RDD seccomp+broker sandbox where Mozilla's
OpenAtTrap rejects fd-relative paths used by systemd's chase()
symlink resolver.
Same approach Chromium uses in media/gpu/v4l2/stateless/ on ChromeOS,
where the sandbox similarly forbids libudev's chase pattern.
No regression: the libudev path runs first and the brute-force path
only activates on its failure. AV_LOG_INFO line announces the
fallback so it's visible in MOZ_LOG=FFmpegLib:5.
Validated on RK3399 / Pinebook Pro / rkvdec:
libudev probe failed (-2), falling back to brute-force /dev/media*
Using V4L2 media driver rkvdec (brute-force) for S264
Reinit context to 1920x1088, pix_fmt: drm_prime
RDD CPU = 4.9%
Bumps pkgrel=2. Worth submitting to Kwiboo's fork upstream.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
First carrier package for the Fourier umbrella. Tracks Kwiboo's
v4l2-request-n8.1 branch (ffmpeg 8.1 base) pinned at commit b57fbbe —
bump _commit to rebase onto newer tip. CI job chained after
claude-his-any so it serializes on the shared aarch64 repo-db;
continue-on-error: true so long ffmpeg builds don't block the debian
downstream.
Deliberately diverges from the AUR package:
- AUR pins 6.1.1 with epoch=2 → would downgrade stock Arch ffmpeg 2:8.1-3.
We track 8.1 so install is a sideways swap, not a regression.
- AUR pulls X11/AMF/CUDA/FireWire/AviSynth/OpenMPT/Bluray/OpenMAX/JPEG-XL/
Theora/XVid/rsvg/soxr/ssh/vidstab/modplug/SDL2/Vulkan/JACK/GSM/Speex —
dropped here; none are needed on a Wayland ARM video-decode fleet.
- AUR uses #branch=…, sha256sums=(SKIP) → every build is tip-of-branch,
not reproducible. We pin via #commit=<sha>.
Kept: encoders (libx264/libx265/libvpx/libdav1d), VAAPI, libdrm, libv4l2,
neon, OpenGL, PulseAudio, subtitle/font stack, gnutls TLS. SDL2 dropped
means no ffplay binary (mpv covers interactive playback).
provides=(ffmpeg) conflicts=(ffmpeg) so it replaces stock ffmpeg on the
target host deliberately. Primary consumers: ohm (Fourier step 5),
fresnel, ampere.
test0r