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daedalus-fourier/include/daedalus.h
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claude-noether a5c47aa51c h264: deblock chroma_v + chroma_h (CPU/NEON, bS<4)
Continues the deblock buildout after PR #9 (luma_h).  Adds the two
chroma orientations via the same recipe-table-routed-to-CPU pattern;
QPU shaders for chroma deblock are still a follow-up.

Scope:
  - Public API: 4 new fns (dispatch + recipe wrapper × {v, h}).
  - Internal: dispatch_h264_deblock_chroma_{v,h}_cpu calling the
    vendored ff_h264_{v,h}_loop_filter_chroma_neon symbols.
  - Recipe table: DAEDALUS_KERNEL_H264_DEBLOCK_CV = 11,
    DAEDALUS_KERNEL_H264_DEBLOCK_CH = 12, both → CPU.  Explicit
    SUBSTRATE_QPU returns -1 (no shader yet).
  - C reference: tests/h264_chroma_loop_filter_ref.c — covers both
    orientations.  Algorithm per H.264 §8.7.2.4 (bS<4 chroma inter):
    tC = tc0_seg + 1 (no luma-style ap/aq side bonus); only p0/q0
    are updated (chroma never modifies p1/p2/q1/q2).
  - Tests: test_deblock_chroma_v (8x4 tile, edge at row 2) +
    test_deblock_chroma_h (4x8 tile, edge at col 2), 4 segments x
    2 cells per segment per spec.

Verified on hertz (Pi 5 / V3D 7.1):

  $ ./build/test_api_h264
  === Phase 8a API smoke: H.264 kernels via recipe dispatch ===
    H264_IDCT4 recipe substrate:      2 (1=CPU, 2=QPU)
    H264_IDCT8 recipe substrate:      2
    H264_DEBLOCK_LV recipe substrate: 2
    H264_QPEL_MC20 recipe substrate:  2
    H264_DEBLOCK_LH recipe substrate: 1 (CPU, no QPU H shader yet)
    H264_DEBLOCK_CV recipe substrate: 1 (CPU)
    H264_DEBLOCK_CH recipe substrate: 1 (CPU)
    H.264 IDCT 4x4: 2048/2048 bytes bit-exact (100.0000%)
    H.264 IDCT 8x8: 2048/2048 bytes bit-exact (100.0000%)
    H.264 deblock luma v: 2048/2048 bytes bit-exact (100.0000%)
    H.264 deblock luma h: 1024/1024 bytes bit-exact (100.0000%)
    H.264 deblock chroma v: 256/256 bytes bit-exact (100.0000%)
    H.264 deblock chroma h: 256/256 bytes bit-exact (100.0000%)
    H.264 qpel mc20: 1024/1024 bytes bit-exact (100.0000%)

  All 7 kernels bit-exact PASS.  Chroma test sizes are smaller (256
  bytes per orientation) because the per-MB chroma deblock surface is
  smaller than luma — accurate to the production geometry.

Why no QPU shader yet (per the established pattern):
  - Chroma deblock is ~25% of total deblock work at 4:2:0 (one quarter
    the pixel count of luma per MB) — modest QPU win even after the
    shader exists.
  - Same R-band considerations as the luma _h follow-up: the V shader
    transpose isn't mechanical, and the 8-cell tile is small enough
    that NEON's per-edge cost (~3 ns) is already inside the budget.
  - Total bench at 1080p: 8160 MBs × 4 chroma edges × 3 ns = ~100 us.
    Negligible compared to the IDCT layer's 10 ms (CPU NEON).

Now coverage in fourier for the bS<4 8-bit 4:2:0 deblock matrix is
complete: luma_v ✓, luma_h ✓, chroma_v ✓, chroma_h ✓.  Remaining
deblock work: bS=4 intra variants (luma + chroma, V + H).

What this unblocks downstream:
  - daedalus-decoder Stage 4 deblock can now dispatch all four bS<4
    edge categories that a typical inter MB needs.
2026-05-24 23:53:09 +02:00

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/*
* daedalus-fourier — public C API.
*
* Stable surface for the integration layer (Phase 8 V4L2 shim,
* libva-v4l2-request-fourier consumer, or any future skin) to
* dispatch per-kernel work to the right substrate per the
* cycle 1-5 deployment recipe.
*
* Recipe (verdict at end of cycles 1-5, see docs/k*_phase7.md):
*
* VP9 IDCT 8x8 → V3D QPU (R=0.92 GREEN; M4 +7.2 %)
* VP9 LPF wd=4 inner → V3D QPU (R=0.41 ORANGE; M4 +6.9 %)
* VP9 MC 8-tap horiz → CPU NEON (R=0.067 RED; M4 -19.5 %)
* VP9 LPF wd=8 inner → V3D QPU (R=0.34 ORANGE; M4 +4.1 %)
* AV1 CDEF 8x8 luma → CPU NEON (R=0.116 ORANGE; QPU = opportunistic helper at 0.4 Mblock/s)
*
* The API exposes BOTH substrates for every kernel — the
* integration layer can override the recipe at runtime if it
* has scheduler knowledge the kernel-level R-band measurement
* didn't capture. The recommended path is to use
* `daedalus_recipe_dispatch_*` which picks the recipe substrate
* automatically.
*
* License: BSD-2-Clause. This header is part of the library API
* boundary; the implementation links against vendored
* LGPL-2.1+ FFmpeg snapshot and BSD-2-Clause dav1d snapshot.
*
* Threading: a `daedalus_ctx *` owns Vulkan + V3D state. A
* context is single-threaded; use one per worker thread if you
* need parallelism on the QPU side. NEON-side dispatch is
* stateless and re-entrant.
*
* ABI: pre-1.0 — no stability guarantees yet. The function names
* and signatures will become ABI-stable at v1.0; until then the
* integration layer should rebuild against the headers it links
* with.
*/
#ifndef DAEDALUS_FOURIER_H
#define DAEDALUS_FOURIER_H
#include <stdint.h>
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
/* -------------------------------------------------------------------
* Substrate selection
*
* Most callers should NOT specify a substrate — use the
* `daedalus_recipe_dispatch_*` family below, which picks the
* substrate per the cycles-1-5 verdict. Explicit substrate
* selection is for benchmarking, debugging, and future
* runtime-aware schedulers.
* ----------------------------------------------------------------- */
typedef enum {
DAEDALUS_SUBSTRATE_AUTO = 0, /* per recipe table */
DAEDALUS_SUBSTRATE_CPU = 1, /* force ARM NEON */
DAEDALUS_SUBSTRATE_QPU = 2, /* force V3D compute */
} daedalus_substrate;
/* -------------------------------------------------------------------
* Context lifecycle
* ----------------------------------------------------------------- */
typedef struct daedalus_ctx daedalus_ctx;
/* Create a context. Initialises V3D Vulkan device if available;
* NEON-only fallback OK if V3D init fails. Returns NULL on alloc
* failure. */
daedalus_ctx *daedalus_ctx_create(void);
/* Same but skip V3D init — for callers that know they want CPU
* only and want a fast-creating context. */
daedalus_ctx *daedalus_ctx_create_no_qpu(void);
/* Returns 1 if QPU dispatch is available on this context, 0 if
* NEON-only. Useful for the integration layer to short-circuit
* QPU dispatch attempts. */
int daedalus_ctx_has_qpu(const daedalus_ctx *ctx);
void daedalus_ctx_destroy(daedalus_ctx *ctx);
/* -------------------------------------------------------------------
* VP9 IDCT 8x8 add — cycle 1 (QPU by recipe)
*
* For each of n_blocks: take 64 int16 coefficients, perform 8x8
* inverse DCT, add to dst[r,c] = clamp(dst[r,c] + ((q + 16)>>5)).
*
* `meta` is an array of (dst_byte_offset, block_x, block_y) for
* each block, where dst_byte_offset is byte offset into dst.
*
* Returns 0 on success, negative errno-like on failure.
* ----------------------------------------------------------------- */
typedef struct {
uint32_t dst_off; /* byte offset into dst */
uint32_t block_x; /* used only by QPU path for placement */
uint32_t block_y;
uint32_t _pad;
} daedalus_idct8_meta;
int daedalus_recipe_dispatch_vp9_idct8(
daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
const int16_t *coeffs, size_t n_blocks,
const daedalus_idct8_meta *meta);
int daedalus_dispatch_vp9_idct8(
daedalus_ctx *ctx,
daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
const int16_t *coeffs, size_t n_blocks,
const daedalus_idct8_meta *meta);
/* -------------------------------------------------------------------
* VP9 LPF wd=4 / wd=8 — cycles 2 and 4 (QPU by recipe)
*
* Loop filter at horizontal edge crossing pixel column 4 of an
* 8x8 block. Per-edge thresholds (E, I, H).
* ----------------------------------------------------------------- */
typedef struct {
uint32_t dst_off; /* byte offset into dst, at col 4 of edge */
int32_t E, I, H;
} daedalus_lpf_meta;
int daedalus_recipe_dispatch_vp9_lpf4(
daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_lpf_meta *meta);
int daedalus_recipe_dispatch_vp9_lpf8(
daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_lpf_meta *meta);
int daedalus_dispatch_vp9_lpf4(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_lpf_meta *meta);
int daedalus_dispatch_vp9_lpf8(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_lpf_meta *meta);
/* -------------------------------------------------------------------
* VP9 MC 8-tap horizontal — cycle 3 (CPU by recipe)
*
* Subpel-fractional 8-tap horizontal filter; mx selects filter
* row. CPU path is the high-performance default; QPU path is
* available but never recommended by the recipe.
* ----------------------------------------------------------------- */
typedef struct {
uint32_t dst_off;
uint32_t src_off; /* raw, no pre-advance — shader handles -3 internally */
int32_t mx;
uint32_t _pad;
} daedalus_mc_meta;
int daedalus_recipe_dispatch_vp9_mc_8h(
daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
const uint8_t *src, size_t src_stride,
size_t n_blocks, const daedalus_mc_meta *meta);
int daedalus_dispatch_vp9_mc_8h(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
const uint8_t *src, size_t src_stride,
size_t n_blocks, const daedalus_mc_meta *meta);
/* -------------------------------------------------------------------
* AV1 CDEF 8x8 luma — cycle 5 (CPU by recipe; QPU opportunistic)
*
* tmp is an array of n_blocks * 192 uint16, with the padded-buffer
* layout that dav1d's NEON expects (stride 16, padding 2-rows-top +
* 2-cols-left + 2-cols-right + 2-rows-bottom). Caller supplies
* tmp populated with either source pixels (if all edges valid) or
* INT16_MIN sentinels at the boundary (if edge filtered out).
* ----------------------------------------------------------------- */
typedef struct {
uint32_t dst_off;
uint32_t tmp_off_u16; /* offset to block-origin in tmp[] (= padded_origin + 2*16+2) */
int32_t pri_strength; /* 1..7 */
int32_t sec_strength; /* 1..4 */
int32_t dir; /* 0..7 */
int32_t damping; /* 1..6 */
} daedalus_cdef_meta;
int daedalus_recipe_dispatch_cdef_8x8(
daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
const uint16_t *tmp,
size_t n_blocks, const daedalus_cdef_meta *meta);
int daedalus_dispatch_cdef_8x8(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
const uint16_t *tmp,
size_t n_blocks, const daedalus_cdef_meta *meta);
/* -------------------------------------------------------------------
* H.264 IDCT 4x4 + add — cycle 6 (CPU by recipe; QPU unused)
*
* Per H.264 §8.5.12.1, integer 4x4 inverse transform. block is
* COLUMN-major: block[c*4 + r] = coefficient at (row r, col c).
* Block is destructively zeroed after the transform (FFmpeg
* convention).
*
* `coeffs` is an array of n_blocks * 16 int16. `dst_off` is byte
* offset into dst per block.
* ----------------------------------------------------------------- */
typedef struct {
uint32_t dst_off;
uint32_t _pad0, _pad1, _pad2;
} daedalus_h264_block_meta;
int daedalus_recipe_dispatch_h264_idct4(daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
int16_t *coeffs, /* not const — destructively zeroed */
size_t n_blocks, const daedalus_h264_block_meta *meta);
int daedalus_dispatch_h264_idct4(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
int16_t *coeffs,
size_t n_blocks, const daedalus_h264_block_meta *meta);
/* H.264 IDCT 8x8 + add — cycle 7 (CPU by recipe).
* Per H.264 §8.5.13.2, integer 8x8 inverse transform.
* `coeffs` is an array of n_blocks * 64 int16, column-major per block.
*/
int daedalus_recipe_dispatch_h264_idct8(daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
int16_t *coeffs,
size_t n_blocks, const daedalus_h264_block_meta *meta);
int daedalus_dispatch_h264_idct8(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
int16_t *coeffs,
size_t n_blocks, const daedalus_h264_block_meta *meta);
/* -------------------------------------------------------------------
* H.264 luma "v_loop_filter" — cycle 8 (CPU primary; QPU opportunistic)
*
* Filter applied VERTICALLY across a HORIZONTAL edge (16 columns
* wide; pix points to row 0 of the bottom block). Non-intra
* (bS < 4) variant.
*
* Each tile is 16 cols × 8 rows of context (rows -4..+3 around
* the edge). dst_off points to row 0 col 0 of the bottom block.
*
* Constraint: dst_off >= 4 * dst_stride (the kernel reads p3 at
* -4*stride). Caller must ensure this.
* ----------------------------------------------------------------- */
typedef struct {
uint32_t dst_off;
int32_t alpha; /* 0..63 typical, table-derived */
int32_t beta; /* 0..63 typical */
int8_t tc0[4]; /* per-segment filter strength; -1 means skip */
} daedalus_h264_deblock_meta;
int daedalus_recipe_dispatch_h264_deblock_luma_v(daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_h264_deblock_meta *meta);
int daedalus_dispatch_h264_deblock_luma_v(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_h264_deblock_meta *meta);
/* H.264 luma "h_loop_filter" — sibling of _v, applies filter
* HORIZONTALLY across a VERTICAL edge (16 rows tall; pix points to
* row 0 of the right block, col 0 = leftmost output column). Same
* non-intra (bS < 4) variant.
*
* Each tile is 8 cols x 16 rows of context (cols -4..+3 around the
* edge). dst_off points to row 0 col 0 of the RIGHT block.
*
* Constraint: (dst_off % dst_stride) >= 4 (the kernel reads p3 at
* pix[-4]). Caller must ensure this.
*
* QPU shader for the H variant is not yet implemented; recipe table
* routes AUTO to CPU NEON. An explicit DAEDALUS_SUBSTRATE_QPU on
* the _h dispatch returns -1 rather than silently degrading.
*/
int daedalus_recipe_dispatch_h264_deblock_luma_h(daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_h264_deblock_meta *meta);
int daedalus_dispatch_h264_deblock_luma_h(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_h264_deblock_meta *meta);
/* H.264 chroma (4:2:0) loop filters — bS<4 variant. Chroma uses
* the SAME daedalus_h264_deblock_meta struct as luma but on smaller
* tiles: 8 cols × 4 rows for V (4 segments of 2 cols), 4 cols × 8
* rows for H (4 segments of 2 rows). Each segment has its own tc0
* strength (tc0[s] applies to both cells in segment s).
*
* Algorithm difference vs luma: chroma updates only p0 and q0
* (never p1/p2/q1/q2) and uses tC = tc0_seg + 1 directly (no
* luma-style ap/aq side-condition bonus).
*
* QPU shaders for chroma deblock not implemented yet; recipe table
* routes AUTO to CPU NEON. Explicit SUBSTRATE_QPU returns -1.
*/
int daedalus_recipe_dispatch_h264_deblock_chroma_v(daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_h264_deblock_meta *meta);
int daedalus_dispatch_h264_deblock_chroma_v(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_h264_deblock_meta *meta);
int daedalus_recipe_dispatch_h264_deblock_chroma_h(daedalus_ctx *ctx,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_h264_deblock_meta *meta);
int daedalus_dispatch_h264_deblock_chroma_h(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, size_t dst_stride,
size_t n_edges, const daedalus_h264_deblock_meta *meta);
/* -------------------------------------------------------------------
* H.264 luma qpel mc20 (8×8, horizontal half-pel) — cycle 9
* (CPU by recipe; per-block 7.6 ns NEON, QPU not viable — see
* docs/k9_h264qpel_mc20.md for the R-band rationale).
*
* Per H.264 §8.4.2.2.1, horizontal half-pel luma 6-tap filter:
* dst[r,c] = clip255((s[r,c-2] - 5*s[r,c-1] + 20*s[r,c]
* + 20*s[r,c+1] - 5*s[r,c+2] + s[r,c+3]
* + 16) >> 5)
*
* Single-stride: dst and src share `stride`; this matches FFmpeg's
* H264QpelContext.put_h264_qpel_pixels_tab[][] convention and the
* vendored ff_put_h264_qpel8_mc20_neon signature.
*
* `src + src_off` points at the leftmost OUTPUT column (col 0); the
* filter reads cols -2..+3, so the caller must guarantee src has at
* least 2 pixels of left context and 3 pixels of right context per
* row. (FFmpeg already maintains an edge-emulated buffer for the
* frame boundary; this matches that contract.)
* ----------------------------------------------------------------- */
typedef struct {
uint32_t dst_off; /* byte offset into dst (block top-left) */
uint32_t src_off; /* byte offset into src (col 0, row 0) */
} daedalus_h264_qpel_meta;
int daedalus_recipe_dispatch_h264_qpel_mc20(daedalus_ctx *ctx,
uint8_t *dst, const uint8_t *src, size_t stride,
size_t n_blocks, const daedalus_h264_qpel_meta *meta);
int daedalus_dispatch_h264_qpel_mc20(daedalus_ctx *ctx, daedalus_substrate sub,
uint8_t *dst, const uint8_t *src, size_t stride,
size_t n_blocks, const daedalus_h264_qpel_meta *meta);
/* -------------------------------------------------------------------
* Recipe query — what does the API recommend for each kernel?
* ----------------------------------------------------------------- */
typedef enum {
DAEDALUS_KERNEL_VP9_IDCT8 = 1,
DAEDALUS_KERNEL_VP9_LPF4_INNER = 2,
DAEDALUS_KERNEL_VP9_MC_8H = 3,
DAEDALUS_KERNEL_VP9_LPF8_INNER = 4,
DAEDALUS_KERNEL_AV1_CDEF_8X8 = 5,
DAEDALUS_KERNEL_H264_IDCT4 = 6,
DAEDALUS_KERNEL_H264_IDCT8 = 7,
DAEDALUS_KERNEL_H264_DEBLOCK_LV = 8,
DAEDALUS_KERNEL_H264_QPEL_MC20 = 9,
DAEDALUS_KERNEL_H264_DEBLOCK_LH = 10,
DAEDALUS_KERNEL_H264_DEBLOCK_CV = 11,
DAEDALUS_KERNEL_H264_DEBLOCK_CH = 12,
} daedalus_kernel;
daedalus_substrate daedalus_recipe_substrate_for(daedalus_kernel k);
#ifdef __cplusplus
}
#endif
#endif /* DAEDALUS_FOURIER_H */