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T

marfrit 0de0288dce Phase 8.10+8.11: libva consumer integration scaffold

Brings daedalus_v4l2 from "standalone test client" to "VAAPI-
discoverable decoder" by adding the surface formats and
media-controller plumbing that libva-v4l2-request-fourier
(sibling repo) requires.

libva-v4l2-request-fourier patches (pushed separately):
- b5b3acf: daedalus_v4l2 added to known_decoder_drivers
- 2146341: meson option gate

This commit (daedalus-v4l2 side, 3 production changes):

1. V4L2_PIX_FMT_NV12 (single-plane) on CAPTURE
   - Added to daedalus_capture_formats[] alongside NV12M + P010
   - daedalus_fill_capture_fmt handles num_planes=1 case
     (sizeimage = W*H*3/2, bytesperline = W)
   - daemon pack_nv12_single_to_plane: Y at base+0,
     interleaved CbCr at base+(stride*H); same byte content
     as NV12M two-plane, different layout
   - Required because libva-v4l2-request-fourier's video.c
     only knows non-multi-plane NV12 (it advertises
     v4l2_mplane=true but uses the single-plane fourcc).
   - Verified byte-exact via test_m2m_stream against
     ffmpeg -pix_fmt nv12 reference (VP9 1080p 10 frames,
     31 MB).

2. V4L2 Request API media ops
   - daedalus_media_ops = { vb2_request_validate,
     v4l2_m2m_request_queue } assigned to mdev.ops before
     media_device_init.
   - Without this, MEDIA_IOC_REQUEST_ALLOC returned
     -ENOTTY and no VAAPI consumer could allocate a
     media_request.

3. Stateless control registration via v4l2_ctrl_new_custom
   - Switched from v4l2_ctrl_new_std_compound(NULL p_def)
     to v4l2_ctrl_new_custom — pattern rkvdec/cedrus/
     hantro use. Adds a no-op s_ctrl callback.

Verification (hertz, Pi 5, 6.12.75+rpt-rpi-2712):

LibVA trace through `ffmpeg -hwaccel vaapi`:
  vaInitialize / Profiles / Entrypoints / CreateConfig /
  QuerySurfaceAttributes / CreateSurfaces / CreateContext
  (cap_pool: 24 slots, 1 plane each) / CreateBuffer
  (slice + picture params) / MEDIA_IOC_REQUEST_ALLOC
  — all succeed.

Standalone NV12 decode path:
  test_m2m_stream vp9_1080_stream.ivf out.nv12 1920 1080 vp9 nv12
  → 10/10 frames, byte-exact vs ffmpeg -pix_fmt nv12

vainfo (via libva-v4l2-request-fourier with our driver):
  7 VAProfile entries with VAEntrypointVLD
  (H264 Main/High/CBaseline/MultiviewHigh/StereoHigh,
   VP9Profile0, AV1Profile0)

What's NOT here (Phase 8.12):

The libva trace stops at VIDIOC_S_EXT_CTRLS returning
EINVAL when populating V4L2_CID_STATELESS_VP9_FRAME on
the request. The compound-control payload validation
against the kernel's expected struct shape rejects.
This isn't a "missing line" fix — it needs proper
stateless control plumbing (the SPS/PPS/SliceParams
get_dims, validate, default-value paths that in-tree
rkvdec/cedrus/hantro implement to satisfy v4l2-core's
std_validate). Documented as Phase 8.12 scope.

The shipped integration is itself a meaningful deliverable:
all the framework scaffolding is in place; the remaining
gap is well-characterised and bounded.

See docs/phase_8_10_11_closure.md for the full trace
analysis + next-phase plan.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

2026-05-18 17:51:16 +00:00

src

Phase 8.10+8.11: libva consumer integration scaffold

2026-05-18 17:51:16 +00:00

CMakeLists.txt

Phase 8.6: dmabuf + AV1 + H.264 + stateless controls

2026-05-18 16:16:06 +00:00

README.md

Initial scaffold: daedalus-v4l2 sibling repo

2026-05-18 14:54:56 +00:00

README.md

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 sibling daedalus-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.txt
src/main.c — event loop, chardev connection
src/parser.c — FFmpeg dlopen wrapper + per-codec dispatch
src/decode_vp9.c, src/decode_av1.c, src/decode_h264.c — per-codec block walkers
src/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.