claude-noether
9797a0daa6
Extends the AV1 OBU encoder pack (PR #22 landed the Sequence Header half) with the two remaining pieces of the per-frame OBU assembly: - av1_synth_temporal_delimiter_obu() — trivial 2-byte OBU (0x12, 0x00) that AV1 temporal units must start with so libavcodec's parser can detect access-unit boundaries. - av1_synth_frame_header_obu() — encodes a Frame Header OBU (AV1 §5.9) from V4L2_CID_STATELESS_AV1_SEQUENCE + V4L2_CID_STATELESS_ AV1_FRAME controls. ## Frame Header scope The encoder covers the libva-v4l2-request common-case path: - frame_type: KEY / INTER / INTRA_ONLY supported. SWITCH returns 0. - tile_info: single-tile uniform-spacing only (forced tile_cols_log2 = tile_rows_log2 = 0). - quantization_params: full coverage (base_q_idx, delta_q_*, qmatrix). - loop_filter_params: full coverage (levels, sharpness, ref/mode deltas). - cdef_params: full coverage. - segmentation: only enabled=0 path supported (returns 0 if enabled). - loop_restoration: only RESTORE_NONE supported (returns 0 if any plane uses Wiener / SGRPROJ / SWITCHABLE). - global_motion: only IDENTITY warp model emitted (returns 0 if any ref uses ROTZOOM / AFFINE / TRANSLATION). - film_grain_params: only "not present" path — returns 0 if the sequence header has FILM_GRAIN_PARAMS_PRESENT set. Out-of-scope branches return 0 so a future decoder.c integration can surface a coverage warning and fall back to direct libavcodec parsing of the original bitstream where the consumer happens to ship a fully-OBU'd access unit. ## Integration status The new primitives are NOT yet wired into decoder.c. The AV1 decode hot path still passes the OUTPUT buffer straight to libavcodec, which works only when the V4L2 consumer is sending a fully-OBU'd access unit (not strictly the V4L2 stateless contract). A real wiring needs a separate kernel-side change: - daedalus_v4l2_proto.h: add struct daedalus_av1_meta mirroring v4l2_ctrl_av1_sequence + v4l2_ctrl_av1_frame - kernel/daedalus_v4l2_main.c: capture V4L2_CID_STATELESS_AV1_{SEQUENCE, FRAME} at device_run, ship over the chardev - daemon/src/chardev_client.c: receive meta - daemon/src/decoder.c: assemble TD + SH + FH + OBU_TILE_GROUP-wrapped OUTPUT bytes, send to libavcodec Tracked as a follow-on. ## Tests test_av1_obu_synth.c grows 5 new cases (9 total, all green on hertz): === av1_synth_temporal_delimiter_obu === temporal delimiter: OK === av1_synth_frame_header_obu === KEY frame 1080p: OK (13 bytes) INTER frame: OK (18 bytes) SWITCH frame rejected: OK segmentation enabled rejected: OK AV1 OBU synth tests PASSED Bit-walk of the KEY-frame happy path confirms the OBU envelope (obu_type=3 = FRAME_HEADER, has_size_field=1, leb128 size byte), then steps through show_existing_frame, frame_type, show_frame, disable_cdf_update, allow_screen_content_tools. Fuller bit-walks would tie the test to encoder details that are spec-driven and already linear in the source; structural smoke + spec-driven linearity is the right gate. Build clean on hertz (Pi 5, Debian trixie, 6.18.29+rpt-rpi-2712, gcc -Wall -Wextra -Wpedantic). No new warnings. Closes daedalus backlog task #159 (AV1 Frame Header OBU synthesiser; decoder.c integration deferred per task notes above).
daedalus-v4l2
V4L2 stateless decoder for the Raspberry Pi 5 / CM5, backed by the
daedalus-fourier kernel library (VP9 + AV1 CDEF + H.264 video
decode kernels on VideoCore VII compute + ARM NEON).
Status: scaffold (2026-05-18). Architecture locked per daedalus-fourier session memory; implementation not yet begun.
What this is
Sibling repo to daedalus-fourier (the kernel library; cycles 1-9 closed).
A two-piece userspace + kernel-module stack that exposes a V4L2
stateless decoder interface (/dev/videoNN) so that
libva-v4l2-request-fourier → firefox-fourier /
chromium-fourier can drive it the same way they drive existing
hardware-decode pipelines on Pi 5 / RK3588.
+-----------------------------------------------------------+
| firefox-fourier / chromium-fourier (existing) |
+-----------------------------------------------------------+
| VA-API |
+-----------------------------------------------------------+
| libva-v4l2-request-fourier (existing, sibling project) |
+-----------------------------------------------------------+
| V4L2 stateless ioctl uAPI |
+-----------------------------------------------------------+
| daedalus-v4l2 kernel module (`kernel/`) |
| - registers /dev/videoNN |
| - parses V4L2 stateless ioctls (VP9/AV1/H.264 controls) |
| - forwards bitstream + controls to userspace daemon |
| via chardev or netlink |
+-----------------------------------------------------------+
| daedalus-v4l2 userspace daemon (`daemon/`) |
| - takes bitstream blobs + per-slice controls |
| - drives FFmpeg parsers via dlopen (Option γ) |
| - dispatches per-block ops via daedalus-fourier |
| public API (daedalus_dispatch_*) |
| - posts decoded frames back to kernel module |
+-----------------------------------------------------------+
| daedalus-fourier kernel library (sibling project) |
| - exports include/daedalus.h public API |
| - per-kernel CPU NEON + opportunistic V3D QPU dispatch |
| - 9 closed cycles across VP9, AV1 CDEF, H.264 |
+-----------------------------------------------------------+
| V3D 7.1 (Mesa userspace v3dv) + ARM NEON (BCM2712) |
+-----------------------------------------------------------+
Why this architecture (Option B + γ + sibling)
Locked by user 2026-05-18 from 3 options in
daedalus-fourier/docs/phase8_scoping.md:
- Option B over A (userspace v4l2loopback): real
/dev/videoNN, proper DRM PRIME / dmabuf for browser zero-copy. - Option γ: dlopen FFmpeg as parser at runtime. No vendoring, fastest to v1.
- Sibling repo: per
project_consumer_targetconvention, V4L2-side work lives outside daedalus-fourier so the kernel-library has a clean API boundary.
Status
Initial scaffold only. See docs/architecture.md for the
deeper design and docs/roadmap.md for the
sub-phase breakdown.
Repo layout
kernel/— Linux kernel module (V4L2 device registration + ioctl handling + userspace chardev bridge). Out-of-tree.daemon/— userspace decoder daemon (linkslibdaedalus_core.afrom sibling daedalus-fourier; uses dlopen for FFmpeg parser).include/— shared headers between kernel and daemon.docs/— architecture + roadmap.
License
Kernel module: GPLv2 (required for kernel-tree compatibility). Userspace daemon: BSD-2-Clause (matches daedalus-fourier).