fresnel-fourier iter3 Phase 6 commit B: NEW src/vp8.c + src/vp8.h

+ 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>
This commit is contained in:
2026-05-08 22:51:12 +00:00
parent 27d82e3cf4
commit 017e27f389
3 changed files with 305 additions and 2 deletions
+4 -2
View File
@@ -47,7 +47,8 @@ sources = [
'h264_slice_header.c',
'request_pool.c',
'cap_pool.c',
'h265.c'
'h265.c',
'vp8.c'
]
headers = [
@@ -70,7 +71,8 @@ headers = [
'h264_slice_header.h',
'request_pool.h',
'cap_pool.h',
'h265.h'
'h265.h',
'vp8.h'
]
includes = [
+263
View File
@@ -0,0 +1,263 @@
/*
* Copyright (C) 2026 Markus Fritsche <fritsche.markus@gmail.com>
*
* fresnel-fourier iter3 Phase 6 commit B: 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 — confirmed by Phase 0 V4L2 inventory + Phase 3
* cross-validator strace).
*
* Reference: FFmpeg libavcodec/v4l2_request_vp8.c (kwiboo branch);
* FFmpeg libavcodec/vaapi_vp8.c (VAAPI source-side
* verification of the field semantics);
* kernel drivers/media/platform/verisilicon/
* hantro_g1_vp8_dec.c (RK3399 hardware reads
* first_part_header_bits + first_part_size to compute
* MB-data DMA offset).
*
* Phase 5 review amendments incorporated (see phase5_iter3_review.md):
* C1 first_part_header_bits = slice->macroblock_offset
* (NOT 0; kernel reads it unconditionally; same formula as
* v4l2_request_vp8.c uses internally)
* C2 first_part_size = slice->partition_size[0] +
* ((macroblock_offset + 7) / 8)
* (recover total partition size from VAAPI's post-parse
* remainder)
* C3 VAProbabilityBufferType (not VAProbabilityDataBufferType)
* C4 (int8_t) cast (not (s8); kernel-internal typedef not in
* userspace UAPI)
* S3 assert(probability_set) runtime guard (kernel has NO
* coeff_probs default fallback; consumer MUST send
* VAProbabilityBufferType per frame)
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include "vp8.h"
#include "context.h"
#include "request.h"
#include "surface.h"
#include <assert.h>
#include <stdint.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/videodev2.h>
#include <linux/v4l2-controls.h>
#include "v4l2.h"
int vp8_set_controls(struct request_data *driver_data,
struct object_context *context_object,
struct object_surface *surface_object)
{
VAPictureParameterBufferVP8 *picture =
&surface_object->params.vp8.picture;
VASliceParameterBufferVP8 *slice =
&surface_object->params.vp8.slice;
VAIQMatrixBufferVP8 *iqmatrix =
&surface_object->params.vp8.iqmatrix;
VAProbabilityDataBufferVP8 *probability =
&surface_object->params.vp8.probability;
bool iqmatrix_set = surface_object->params.vp8.iqmatrix_set;
bool probability_set = surface_object->params.vp8.probability_set;
struct v4l2_ctrl_vp8_frame frame;
struct object_surface *last_ref;
struct object_surface *golden_ref;
struct object_surface *alt_ref;
int rc;
int i, j;
memset(&frame, 0, sizeof frame);
/* Phase 5 S3: kernel has no coeff_probs default fallback. The
* VAAPI consumer chain (FFmpeg's vaapi_vp8.c:146-148, used by
* mpv and ffmpeg-vaapi) always sends VAProbabilityBufferType
* per frame. Surface immediately if a future consumer doesn't. */
assert(probability_set);
/* Clause 3: frame geometry + per-frame scalars */
frame.width = picture->frame_width;
frame.height = picture->frame_height;
frame.horizontal_scale = 0; /* not exposed by VAAPI */
frame.vertical_scale = 0;
frame.version = picture->pic_fields.bits.version;
frame.prob_skip_false = picture->prob_skip_false;
frame.prob_intra = picture->prob_intra;
frame.prob_last = picture->prob_last;
frame.prob_gf = picture->prob_gf;
/* Phase 3 Q2: VAAPI counts include control partition;
* kernel counts DCT only — off-by-one. */
frame.num_dct_parts = slice->num_of_partitions - 1;
/* Clause 4: DPB timestamp resolution (mirrors mpeg2.c pattern;
* NULL surface → timestamp stays 0 from memset). */
last_ref = SURFACE(driver_data, picture->last_ref_frame);
golden_ref = SURFACE(driver_data, picture->golden_ref_frame);
alt_ref = SURFACE(driver_data, picture->alt_ref_frame);
if (last_ref != NULL)
frame.last_frame_ts =
v4l2_timeval_to_ns(&last_ref->timestamp);
if (golden_ref != NULL)
frame.golden_frame_ts =
v4l2_timeval_to_ns(&golden_ref->timestamp);
if (alt_ref != NULL)
frame.alt_frame_ts =
v4l2_timeval_to_ns(&alt_ref->timestamp);
/* Clause 5: loop filter mapping */
for (i = 0; i < 4; i++) {
frame.lf.ref_frm_delta[i] =
picture->loop_filter_deltas_ref_frame[i];
frame.lf.mb_mode_delta[i] =
picture->loop_filter_deltas_mode[i];
}
frame.lf.sharpness_level = picture->pic_fields.bits.sharpness_level;
frame.lf.level = picture->loop_filter_level[0];
if (picture->pic_fields.bits.loop_filter_adj_enable)
frame.lf.flags |= V4L2_VP8_LF_ADJ_ENABLE;
if (picture->pic_fields.bits.mode_ref_lf_delta_update)
frame.lf.flags |= V4L2_VP8_LF_DELTA_UPDATE;
if (picture->pic_fields.bits.filter_type)
frame.lf.flags |= V4L2_VP8_LF_FILTER_TYPE_SIMPLE;
/* Clause 6: quantization base + delta derivation */
if (iqmatrix_set) {
frame.quant.y_ac_qi =
iqmatrix->quantization_index[0][0];
frame.quant.y_dc_delta = (int8_t)
(iqmatrix->quantization_index[0][1] -
iqmatrix->quantization_index[0][0]);
frame.quant.y2_dc_delta = (int8_t)
(iqmatrix->quantization_index[0][2] -
iqmatrix->quantization_index[0][0]);
frame.quant.y2_ac_delta = (int8_t)
(iqmatrix->quantization_index[0][3] -
iqmatrix->quantization_index[0][0]);
frame.quant.uv_dc_delta = (int8_t)
(iqmatrix->quantization_index[0][4] -
iqmatrix->quantization_index[0][0]);
frame.quant.uv_ac_delta = (int8_t)
(iqmatrix->quantization_index[0][5] -
iqmatrix->quantization_index[0][0]);
}
if (picture->pic_fields.bits.segmentation_enabled && iqmatrix_set) {
for (i = 1; i < 4; i++)
frame.segment.quant_update[i] = (int8_t)
(iqmatrix->quantization_index[i][0] -
iqmatrix->quantization_index[0][0]);
}
/* Clause 7: segment fields */
for (i = 0; i < 3; i++)
frame.segment.segment_probs[i] =
picture->mb_segment_tree_probs[i];
if (picture->pic_fields.bits.segmentation_enabled)
frame.segment.flags |= V4L2_VP8_SEGMENT_FLAG_ENABLED;
if (picture->pic_fields.bits.update_mb_segmentation_map)
frame.segment.flags |= V4L2_VP8_SEGMENT_FLAG_UPDATE_MAP;
if (picture->pic_fields.bits.update_segment_feature_data)
frame.segment.flags |=
V4L2_VP8_SEGMENT_FLAG_UPDATE_FEATURE_DATA;
/* DELTA_VALUE_MODE: VAAPI doesn't expose abs_delta. FFmpeg sets
* unconditionally per !s->segmentation.absolute_vals (default).
* Kernel ignores when ENABLED bit clear (BBB case). */
frame.segment.flags |= V4L2_VP8_SEGMENT_FLAG_DELTA_VALUE_MODE;
if (picture->pic_fields.bits.segmentation_enabled) {
for (i = 0; i < 4; i++)
frame.segment.lf_update[i] = (int8_t)
(picture->loop_filter_level[i] -
picture->loop_filter_level[0]);
}
/* Clause 8: entropy table mapping (3 VAAPI sources merged) */
for (i = 0; i < 4; i++)
frame.entropy.y_mode_probs[i] = picture->y_mode_probs[i];
for (i = 0; i < 3; i++)
frame.entropy.uv_mode_probs[i] = picture->uv_mode_probs[i];
for (i = 0; i < 2; i++)
for (j = 0; j < 19; j++)
frame.entropy.mv_probs[i][j] =
picture->mv_probs[i][j];
/* coeff_probs[4][8][3][11]: VAAPI layout matches kernel exactly;
* direct memcpy. Both vaapi_vp8.c:133-143 and v4l2_request_vp8.c:
* 141-153 apply identical coeff_bands_inverse reordering before
* writing — VAAPI consumer has done the reordering for us. */
memcpy(frame.entropy.coeff_probs,
probability->dct_coeff_probs,
sizeof frame.entropy.coeff_probs);
/* Clause 9: coder state + first-partition fields */
frame.coder_state.range = picture->bool_coder_ctx.range;
frame.coder_state.value = picture->bool_coder_ctx.value;
frame.coder_state.bit_count = picture->bool_coder_ctx.count;
/* Phase 5 C1+C2: macroblock_offset IS first_part_header_bits by
* source identity; kernel hantro_g1_vp8_dec.c:260 reads it
* unconditionally to compute MB-data DMA offset. partition_size[0]
* is the post-parse REMAINDER; recover total via
* + ceil(macroblock_offset/8). */
frame.first_part_header_bits = slice->macroblock_offset;
frame.first_part_size =
slice->partition_size[0] +
((uint32_t)slice->macroblock_offset + 7) / 8;
for (i = 0; i < 8; i++)
frame.dct_part_sizes[i] = slice->partition_size[i + 1];
/* Clause 9: flags assembly (6 mainline-documented bits only;
* EXPERIMENTAL + bit 0x40 NOT replicated despite ffmpeg-v4l2-
* request-git setting them — kernel hantro_vp8.c only inspects
* KEY_FRAME bit). VAAPI inverts: key_frame=0 means it IS a
* keyframe per VP8 spec. */
if (!picture->pic_fields.bits.key_frame)
frame.flags |= V4L2_VP8_FRAME_FLAG_KEY_FRAME;
frame.flags |= V4L2_VP8_FRAME_FLAG_SHOW_FRAME;
if (picture->pic_fields.bits.mb_no_coeff_skip)
frame.flags |= V4L2_VP8_FRAME_FLAG_MB_NO_SKIP_COEFF;
if (picture->pic_fields.bits.sign_bias_golden)
frame.flags |= V4L2_VP8_FRAME_FLAG_SIGN_BIAS_GOLDEN;
if (picture->pic_fields.bits.sign_bias_alternate)
frame.flags |= V4L2_VP8_FRAME_FLAG_SIGN_BIAS_ALT;
/* Clause 1+10: single-control batched submission */
struct v4l2_ext_control ctrls[1] = {
{
.id = V4L2_CID_STATELESS_VP8_FRAME,
.ptr = &frame,
.size = sizeof frame,
},
};
rc = v4l2_set_controls(driver_data->video_fd,
surface_object->request_fd,
ctrls, 1);
if (rc < 0)
return VA_STATUS_ERROR_OPERATION_FAILED;
return 0;
}
+38
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@@ -0,0 +1,38 @@
/*
* Copyright (C) 2026 Markus Fritsche <fritsche.markus@gmail.com>
*
* fresnel-fourier iter3: VP8 codec dispatcher header.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#ifndef _VP8_H_
#define _VP8_H_
struct object_context;
struct object_surface;
struct request_data;
int vp8_set_controls(struct request_data *driver_data,
struct object_context *context,
struct object_surface *surface_object);
#endif