claude-noether
017e27f389
+ meson.build VP8 entries
Net-new VP8 codec dispatcher implemented against
V4L2_CID_STATELESS_VP8_FRAME (kernel UAPI <linux/v4l2-controls.h>:
1900-1958). Single batched control per frame, no init-time device-
wide menus (VP8 has no DECODE_MODE/START_CODE).
Per-frame submission: ONE VIDIOC_S_EXT_CTRLS, count=1, with full
v4l2_ctrl_vp8_frame struct (1232 bytes — corrected vs Phase 2
implicit ~400 estimate; entropy.coeff_probs[4][8][3][11] alone is
1056 bytes).
vp8_set_controls() implements 10 contract clauses per
phase4_iter3_plan.md:
Clause 1: single-control batched submission (count=1)
Clause 2: stack alloc + memset zero (covers all padding)
Clause 3: width/height/version/per-frame scalars; off-by-one
num_dct_parts = num_of_partitions - 1
Clause 4: DPB timestamp resolution (3 refs: last/golden/alt;
NULL surface → 0-sentinel via memset; mirrors iter1
mpeg2.c::pic.forward_ref_ts)
Clause 5: loop filter (6 fields + 3 flag bits; ADJ_ENABLE/
DELTA_UPDATE/FILTER_TYPE_SIMPLE)
Clause 6: quant base + delta derivation from VAAPI's per-segment
absolute index matrix (subtraction recovers signed
deltas; correct for typical content per Phase 5 S1)
Clause 7: segment fields (segment_probs direct copy; flags
assembled with DELTA_VALUE_MODE set unconditionally
per FFmpeg pattern)
Clause 8: entropy table — 3 VAAPI sources merged (Picture: y_mode +
uv_mode + mv_probs; ProbabilityData: coeff_probs[4][8][3]
[11] direct memcpy; IQMatrix: quant)
Clause 9: coder state + first-partition fields + flags assembly
Clause 10: v4l2_set_controls submission
Phase 5 review amendments incorporated:
C1 first_part_header_bits = slice->macroblock_offset
NOT 0 — kernel hantro_g1_vp8_dec.c:260 + rockchip_vpu2_hw_vp8_
dec.c:372 read this field unconditionally to compute the MB-
data DMA offset. Verified via source identity: vaapi_vp8.c:204
and v4l2_request_vp8.c:83 use byte-identical formulas
(8 * (input - data) - bit_count - 8); VAAPI exposes via
slice->macroblock_offset, V4L2 names it first_part_header_bits.
C2 first_part_size = slice->partition_size[0] +
((macroblock_offset + 7) / 8)
VAAPI's partition_size[0] is the REMAINING bytes after parsing
(vaapi_vp8.c:209; va_dec_vp8.h:193-196). Kernel needs the
TOTAL control partition size; recover by adding back ceil
(macroblock_offset/8) bytes.
Phase 3 keyframe verbatim cross-check: 21923 + 819 = 22742 ✓
C4 (int8_t) cast (NOT (s8); s8 is kernel-internal typedef from
<linux/types.h> not exposed to userspace; userspace UAPI
exposes __s8 with double-underscore; portable userspace cast
is int8_t from <stdint.h>).
S3 assert(probability_set) — kernel hantro_vp8.c::hantro_vp8_
prob_update reads coeff_probs unconditionally; NO default-
table fallback. Practical risk low (FFmpeg vaapi_vp8.c always
sends VAProbabilityBufferType per frame), but assert surfaces
immediately if a future consumer doesn't.
Flags assembly: 6 mainline-documented bits only (KEY_FRAME, SHOW_
FRAME, MB_NO_SKIP_COEFF, SIGN_BIAS_GOLDEN, SIGN_BIAS_ALT). EXP +
bit 0x40 NOT replicated despite ffmpeg-v4l2-request-git setting
them on inter frames — kernel hantro_vp8.c only inspects KEY_FRAME
bit. SHOW_FRAME forced unconditional per Phase 3 Q4 (BBB has no
alt-ref invisible frames; documented fidelity gap).
VAAPI inverts: key_frame=0 means it IS a keyframe per VP8 spec.
Backend writes V4L2_VP8_FRAME_FLAG_KEY_FRAME iff
!picture->pic_fields.bits.key_frame.
After this commit alone: vp8.o compiles standalone; meson.build
links it into the shared library. picture.c can't dispatch yet
(commit C wires that).
Refs:
../fresnel-fourier/phase4_iter3_plan.md (10 contract clauses,
Phase 5 amendments
section)
../fresnel-fourier/phase5_iter3_review.md (C1, C2, C3, C4, S3
all incorporated)
../fresnel-fourier/phase3_iter3_baseline.md (verbatim payload
anchors)
references/ffmpeg-kwiboo/libavcodec/v4l2_request_vp8.c (V4L2 ref)
references/ffmpeg-kwiboo/libavcodec/vaapi_vp8.c (VAAPI source ref)
references/linux-mainline/drivers/media/platform/verisilicon/
hantro_g1_vp8_dec.c (RK3399 kernel driver — first_part_header_
bits + first_part_size usage)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
39 lines
1.4 KiB
C
39 lines
1.4 KiB
C
/*
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* Copyright (C) 2026 Markus Fritsche <fritsche.markus@gmail.com>
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*
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* fresnel-fourier iter3: VP8 codec dispatcher header.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#ifndef _VP8_H_
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#define _VP8_H_
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struct object_context;
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struct object_surface;
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struct request_data;
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int vp8_set_controls(struct request_data *driver_data,
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struct object_context *context,
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struct object_surface *surface_object);
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#endif
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