marfrit
8c1d9960c4
libva-v4l2-request-fourier (and any V4L2-stateless-API consumer)
passes H.264 SPS/PPS as separate V4L2_CID_STATELESS_H264_{SPS,PPS}
controls; only the slice NAL goes into the OUTPUT buffer. This is
correct per the V4L2 stateless contract. But libavcodec — which
the daedalus daemon uses for actual decode (Option γ) — wants a
self-contained AnnexB stream including SPS+PPS before any slice.
Result on higgs: "non-existing PPS 0 referenced" + decode_slice_
header errors on every H.264 frame, even after LIBVA-1 and -2
routing correctly delivered the request to the daemon.
Fix splits across kernel + daemon, keeping the kernel module as a
thin transport and putting the actual NAL encoding in userspace:
include/daedalus_v4l2_proto.h:
Add struct daedalus_h264_meta (the four v4l2_ctrl_h264_*
structs the kernel collects) and DAEDALUS_REQ_FLAG_H264_META
(set in req.flags when the meta block is present between the
daedalus_req_decode prefix and the slice bitstream).
kernel/daedalus_v4l2_main.c:
Add daedalus_collect_h264_meta() — reads the H.264 ctrl values
from the bound media_request via v4l2_ctrl_find +
ctrl->p_cur.p_h264_*. device_run() calls it on H.264 codec_id,
copies the structs into the REQ_DECODE payload between the
prefix and bitstream, and sets the flag. Payload size is
bounds-checked against DAEDALUS_PROTO_MAX_PAYLOAD so an over-
sized slice + meta fails loud instead of truncating.
daemon/src/bitstream_writer.{c,h}:
New module — MSB-first bit packer with H.264 Exp-Golomb ue(v)
and se(v) coding + rbsp_trailing_bits alignment. Sticky
overflow flag so callers can verify the output buffer wasn't
truncated.
daemon/src/h264_nal_synth.{c,h}:
New module — turns v4l2_ctrl_h264_sps / v4l2_ctrl_h264_pps
into AnnexB-framed NAL units per ITU-T H.264 7.3.2.1 / 7.3.2.2.
Emits emulation prevention bytes (0x03 after every 00 00 in the
EBSP) and the 4-byte start code (0x00000001). Coverage matches
what V4L2 stateless surface gives us: VUI parameters and full
scaling matrices are NOT emitted (V4L2 doesn't carry them — the
seq_scaling_matrix_present_flag is set to 0 and libavcodec uses
flat defaults, which matches the de-facto behaviour of most
H.264 streams libva-v4l2-request drives).
daemon/src/decoder.c:
daedalus_decoder_run_request() now takes an optional
h264_meta parameter. For codec_id == H264 with meta != NULL,
synthesises SPS+PPS NAL units, allocates a combined
[SPS][PPS][slice] buffer (+ AV_INPUT_BUFFER_PADDING_SIZE), and
feeds that to avcodec_send_packet instead of the raw slice.
VP9/AV1 path unchanged (frames are self-contained). Cleanup
now goes through a unified `out:` label so the assembled
buffer is always freed on every exit (including the existing
decoder_open_codec / no-frame / receive_frame failure paths).
daemon/src/chardev_client.c:
handle_req_decode() peels off the optional meta block when the
flag is set, passes it through to the decoder, and updates
the payload-length consistency check (now allows for an extra
sizeof(daedalus_h264_meta) when the flag is on).
Build (boltzmann aarch64): clean compile of all daemon sources,
including bitstream_writer + h264_nal_synth + the refactored
decoder.c. Kernel module compile to be verified via DKMS rebuild
on higgs in the marfrit-packages bump that follows.
Test plan: with this commit + a marfrit-packages daedalus pin
bump, higgs's ffmpeg -hwaccel vaapi -i h264_test.mp4 should
produce a successful decode (vs. the previous "non-existing PPS 0
referenced" failure). The daemon log should show:
decoder: opened h264 context
decoder: h264 prepended SPS=NB PPS=MB slice=KB
decoder: OK 320x240 fmt=0 (yuv420p) fnv1a=0x...
VP9 / AV1 behaviour unchanged — they don't carry meta and the
existing per-frame self-describing path still applies.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
89 lines
3.0 KiB
C
89 lines
3.0 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
|
|
/*
|
|
* decoder.h — FFmpeg-driven decode helper for daedalus-v4l2 daemon.
|
|
*
|
|
* Encapsulates the AVCodecContext per supported codec, plus a
|
|
* single shared AVPacket / AVFrame pair (we serialise decode
|
|
* inside the chardev event loop; no concurrency).
|
|
*
|
|
* Phase 8.4 implements VP9. Phase 8.6 extends to AV1 / H.264.
|
|
*/
|
|
#ifndef DAEDALUS_V4L2_DECODER_H
|
|
#define DAEDALUS_V4L2_DECODER_H
|
|
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
|
|
#include "daedalus_v4l2_proto.h"
|
|
#include "dmabuf_capture.h"
|
|
|
|
struct ffmpeg_loader;
|
|
struct AVCodecContext;
|
|
struct AVPacket;
|
|
struct AVFrame;
|
|
|
|
/**
|
|
* struct daedalus_decoder - per-daemon decoder state
|
|
* @loader: borrowed FFmpeg loader (must outlive the decoder)
|
|
* @ctx_vp9: lazily-opened VP9 AVCodecContext (NULL until first
|
|
* VP9 REQ_DECODE)
|
|
* @ctx_av1: lazily-opened AV1 AVCodecContext
|
|
* @ctx_h264: lazily-opened H.264 AVCodecContext
|
|
* @pkt: shared AVPacket reused across requests
|
|
* @frame: shared AVFrame reused across requests
|
|
*/
|
|
struct daedalus_decoder {
|
|
struct ffmpeg_loader *loader;
|
|
struct AVCodecContext *ctx_vp9;
|
|
struct AVCodecContext *ctx_av1;
|
|
struct AVCodecContext *ctx_h264;
|
|
struct AVPacket *pkt;
|
|
struct AVFrame *frame;
|
|
};
|
|
|
|
/**
|
|
* daedalus_decoder_init - allocate the shared packet/frame pair
|
|
*
|
|
* Return: 0 on success, -ENOMEM if FFmpeg refused to allocate.
|
|
* Codec contexts are opened lazily on first use.
|
|
*/
|
|
int daedalus_decoder_init(struct daedalus_decoder *dec,
|
|
struct ffmpeg_loader *loader);
|
|
|
|
/**
|
|
* daedalus_decoder_cleanup - free codec contexts, packet, frame
|
|
*/
|
|
void daedalus_decoder_cleanup(struct daedalus_decoder *dec);
|
|
|
|
/**
|
|
* daedalus_decoder_run_request - decode one REQ_DECODE payload
|
|
* @dec: initialised decoder
|
|
* @req: REQ_DECODE prefix (from the wire)
|
|
* @bitstream: bitstream blob (req->bitstream_len bytes)
|
|
* @h264_meta: optional H.264 SPS/PPS metadata; non-NULL only when
|
|
* codec_id == H264 and the kernel set DAEDALUS_REQ_FLAG_
|
|
* H264_META. Used to synthesise the AnnexB SPS+PPS NALs
|
|
* libavcodec needs before any slice (libva-v4l2-request
|
|
* passes only the slice in @bitstream per the V4L2
|
|
* stateless API contract). NULL for VP9/AV1 paths.
|
|
* @resp: caller-allocated RESP_FRAME output (zeroed by callee)
|
|
* @planes: mapped CAPTURE planes (Phase 8.6 dmabuf path). If
|
|
* NULL or planes->nr == 0, the decoder runs but
|
|
* writes no pixels — caller still gets dims + digest.
|
|
*
|
|
* Populates @resp with the decode outcome and writes decoded
|
|
* pixels (NV12 layout: Y to plane 0, interleaved CbCr to plane
|
|
* 1) directly into the mapped dmabuf planes. Always returns
|
|
* 0; decode-level failures are reported via @resp->status so
|
|
* the kernel sees a structured response rather than a dropped
|
|
* request.
|
|
*/
|
|
int daedalus_decoder_run_request(struct daedalus_decoder *dec,
|
|
const struct daedalus_req_decode *req,
|
|
const uint8_t *bitstream,
|
|
const struct daedalus_h264_meta *h264_meta,
|
|
struct daedalus_resp_frame *resp,
|
|
const struct daedalus_capture_planes *planes);
|
|
|
|
#endif /* DAEDALUS_V4L2_DECODER_H */
|