forked from marfrit/marfrit-packages
marfrit
e641d679d3
First cycle of the libavcodec.so substitution arc (reauktion/daedalus-v4l2#11 step 2). H264DSPContext.idct_add — called per 4×4 block from the intra-4×4 decode path in libavcodec/h264_mb.c — now dispatches through daedalus_recipe_dispatch_h264_idct4 instead of ff_h264_idct_add_neon. ## What - Add 0003-h264-idct4-daedalus-fourier.patch (in both arch/ and debian/ ffmpeg-v4l2-request-fourier/). Creates libavcodec/aarch64/h264_idct_daedalus.c (ff_h264_idct_add_daedalus shim + lazy pthread_once context init via daedalus_ctx_create_no_qpu), patches libavcodec/aarch64/h264dsp_init_aarch64.c to wire c->idct_add to the shim, adds the new .o to libavcodec/aarch64/Makefile. - arch/PKGBUILD + debian/build-deb.sh: fetch + build daedalus-fourier (pinned at d87239d — lockstep with the daedalus-v4l2 daemon's inline build) with -DCMAKE_POSITION_INDEPENDENT_CODE=ON into a per-build temp prefix, then pass --extra-cflags=-I.../include --extra-ldflags=-L.../lib --extra-libs="-ldaedalus_core -lvulkan -lpthread" to FFmpeg configure. daedalus_core.a is static-linked into libavcodec.so.62. - debian/control Depends gains libvulkan1 (daedalus_core PUBLIC-links Vulkan::Vulkan for the queryable QPU substrate; the no-QPU constructor still works at runtime but the loader needs libvulkan.so.1 present to dlopen libavcodec.so.62). - arch/PKGBUILD depends gains vulkan-icd-loader, makedepends gains cmake / ninja / vulkan-headers. ## Why The recipe layer picks the substrate; for cycle 6 (H.264 IDCT 4×4) the recipe is CPU NEON, so this is effectively a NEON-to-NEON substitution with one extra dispatch call and recipe-table lookup. The point of this first cycle isn't perf wins — it's plumbing. Once the path is wired and stable, follow-up patches batch through the bulk paths (idct_add16 / idct_add16intra / idct_add8) and stack cycles 7/8/9 (IDCT 8×8, luma-v deblock, qpel mc20). Bit-exact against ff_h264_idct_add_neon (daedalus-fourier cycle 6 green; FFmpeg's 4×4 block storage matches daedalus's column-major convention). ## Scope NOT covered - Bulk paths (idct_add16 / idct_add16intra / idct_add8) — most IDCT 4×4 calls in real H.264 streams go through these, not the per- block c->idct_add path; intra-4×4-only macroblocks are a minority. Batched substitution lands in a follow-up. - High-bit-depth (10-bit) path — not touched; 8-bit only. - Cycles 7/8/9 — separate PRs. ## SONAME Unchanged. libavcodec.so.62 / libavformat.so.62 / libavutil.so.60. No daedalus-v4l2-dkms or daedalus-v4l2 bump required. ## Refs - reauktion/daedalus-v4l2 issue #11 (substitution arc): reauktion/daedalus-v4l2#11 - marfrit/daedalus-fourier cycle 6 close (H.264 IDCT 4×4 NEON green)