claude-noether
88b2ebfaa9
First incremental step toward H.264 daemon-rewrite (daedalus-v4l2#11):
make the daedalus-fourier kernel library available to the daemon
process so subsequent patches can substitute its primitives
(IDCT 4×4, IDCT 8×8, luma vertical deblock, etc.) for libavcodec's
per-MB pixel math.
This patch does NOT yet dispatch any kernels. It only:
- Adds `pkg_check_modules(DAEDALUS_FOURIER REQUIRED daedalus-fourier)`
to the daemon's CMakeLists, with explicit link ordering
(libdaedalus_core.a must precede -lvulkan because the static
archive references vulkan symbols and the linker resolves
left-to-right). We bypass IMPORTED_TARGET because pkg-config's
Requires.private chain leaves CMake's dependency graph reordering
the archive after -lvulkan, breaking the static link.
- Calls daedalus_ctx_create_no_qpu() at daemon startup, logs the
substrate-availability line, destroys the context at exit.
no_qpu mode skips V3D Vulkan probe — proves linkage works
without depending on shader-path resolution (which is a
separate piece of work, since v3d_runner currently loads
.spv files from cwd-relative paths and consumer would need
a search path override).
Sample journal line:
[2026-05-21 17:59:35.271 INFO] daedalus-fourier: linked, ctx alive
(no_qpu mode; has_qpu=0)
Build-test verified on hertz (Pi 5 dev host) against an installed
copy of daedalus-fourier r35+gd87239d (from marfrit/daedalus-fourier
PR #1). Binary links cleanly, --help prints, daemon mode opens
chardev (fails predictably on hertz which has no daedalus_v4l2
kmod; on higgs this is the existing working path).
Follow-up patches per daedalus-v4l2#11:
1. Instrument the existing libavcodec decode path to count
per-frame IDCT blocks / deblock edges / MC tiles so we have
a baseline of what work the daemon dispatches for a typical
YouTube H.264 stream.
2. Substitute daedalus-fourier kernels one at a time, measuring
CPU saved per substitution.
3. Wire shader path resolution into daedalus_ctx_create() for
the QPU substrate (V3D opportunistic helper paths).
Wire protocol unchanged. DAEDALUS_PROTO_VERSION stays at 0.
daemon/ — daedalus-v4l2 userspace decoder daemon
Userspace daemon that:
- Connects to the kernel module's chardev
- Receives bitstream + V4L2 control blobs
- Parses bitstream via dlopen'd FFmpeg
- Dispatches per-block work via
daedalus_dispatch_*from siblingdaedalus-fourier - Returns decoded frames to kernel
Status
Scaffold only. Phase 8.3 not yet started.
Build dependencies (planned)
- libdaedalus_core.a from sibling daedalus-fourier (static link)
- FFmpeg dev headers (for AVPacket/AVCodec interface types) + runtime FFmpeg .so (loaded via dlopen)
- libv4l2 (for V4L2 control struct definitions)
- pthread
Build (when implemented)
mkdir build && cd build
cmake .. -DDAEDALUS_FOURIER_DIR=/path/to/daedalus-fourier
make
Layout (planned)
CMakeLists.txtsrc/main.c— event loop, chardev connectionsrc/parser.c— FFmpeg dlopen wrapper + per-codec dispatchsrc/decode_vp9.c,src/decode_av1.c,src/decode_h264.c— per-codec block walkerssrc/frame_io.c— frame allocation, return to kernel
License
BSD-2-Clause (matches daedalus-fourier sibling).
Phase 8.3 starting point
A standalone program that:
- Opens a .ivf or .mp4
- Pulls codec packets via dlopen'd avformat
- Calls dlopen'd avcodec to parse (without decoding)
- Walks the block-level metadata
- Validates output structure
No kernel involvement yet — just confirm the parse path works.