Cycle 8 of the libavcodec.so substitution arc (reauktion/daedalus-v4l2#11
step 2). H264DSPContext.v_loop_filter_luma — non-intra bS<4 vertical
luma deblock, called per macroblock-row edge from the slice deblock
loop in libavcodec/h264_loopfilter.c — now dispatches through
daedalus_recipe_dispatch_h264_deblock_luma_v instead of
ff_h264_v_loop_filter_luma_neon.
## What
- Add 0005-h264-deblock-luma-v-daedalus-fourier.patch (in both arch/
and debian/ ffmpeg-v4l2-request-fourier/). Extends
libavcodec/aarch64/h264_idct_daedalus.c with
ff_h264_v_loop_filter_luma_daedalus (constructs a
daedalus_h264_deblock_meta from FFmpeg's (alpha, beta, tc0[4]) and
calls daedalus_recipe_dispatch_h264_deblock_luma_v with n_edges=1).
Patches libavcodec/aarch64/h264dsp_init_aarch64.c to wire
c->v_loop_filter_luma to the new shim.
- arch/PKGBUILD + debian/build-deb.sh: append patch + bump pkgrel/PKGREL
to 8.
- No new build-deps, no Depends change, no daedalus-fourier rev — the
d87239d pin already exposes daedalus_recipe_dispatch_h264_deblock_luma_v.
## Why
Cycle 8 is marked "CPU primary; QPU opportunistic" in the daedalus-
fourier API docstring. Per the hybrid substrate philosophy
("if there's a coprocessor, use it") we eventually want the QPU
opportunism active here. But the libavcodec.so context is
process-global and shared with cycles 6/7 via pthread_once, and it
uses daedalus_ctx_create_no_qpu deliberately to avoid implicit
Vulkan init in arbitrary host processes (Firefox content, mpv-fourier,
ffmpeg-fourier CLI, ...). Switching to daedalus_ctx_create here
without a feature flag would be a footgun.
So cycle 8 lands as plumbing-only NEON-by-recipe substitution for
now; opportunistic QPU enablement is a separate follow-up that adds
a DAEDALUS_FOURIER_ENABLE_QPU env var or equivalent.
## Scope NOT covered
- Intra (bS=4) loop filter c->v_loop_filter_luma_intra — daedalus's
daedalus_h264_deblock_meta only covers the non-intra path.
- Horizontal-edge variant c->h_loop_filter_luma — separate kernel
(not yet in daedalus-fourier API).
- Chroma loop filters — separate kernels.
- Bulk batching — single-edge dispatch wastes the kernel's n_edges>1
amortization. Same caveat as cycles 6/7; follow-up.
- QPU opportunism — see "Why" above.
## SONAME
Unchanged. libavcodec.so.62 / libavformat.so.62 / libavutil.so.60.
## Refs
- reauktion/daedalus-v4l2 issue #11: reauktion/daedalus-v4l2#11
- marfrit-packages PR #76 (cycle 6 IDCT 4×4)
- marfrit-packages PR #85 (cycle 7 IDCT 8×8)
- marfrit/daedalus-fourier cycle 8 close (deblock luma-v NEON green)
