Commit Graph

12 Commits

Author SHA1 Message Date
claude-noether 1113953f97 h264: qpel avg anchors (avg_mc20/02/22, biprediction support)
Begins the avg_ qpel buildout for B-slice biprediction.  Each avg_
form computes the same half-pel formula as its put_ sibling, then
L2-averages the result with the existing dst contents — the caller
pre-loads dst with the list0 prediction; the avg_ call adds list1
per H.264 §8.4.2.3.1.

Scope (3 anchors, sets the pattern for the remaining 13 avg_
variants):
  - 3 new kernel enums (AVG_MC20=31, AVG_MC02=32, AVG_MC22=33) → CPU.
  - 3 NEON externs for the vendored ff_avg_h264_qpel8_{mc20,mc02,mc22}_neon.
  - 3 CPU dispatches via existing DEFINE_QPEL_CPU_DISPATCH macro
    (the macro is type-agnostic so it didn't need changes for avg_).
  - 3 public dispatches via DEFINE_QPEL_DISPATCH macro.
  - 3 recipe wrappers via DEFINE_QPEL_RECIPE macro.
  - tests/h264_qpel8_avg_anchors_ref.c — per-cell helpers + L2 avg.
  - Test harness: run_avg_qpel() seeds dst with random content so
    the L2 averaging is actually exercised (not just put_-style
    overwrite that would silently pass).

Verified on hertz:

  $ ./build/test_api_h264 | tail -3
    H.264 qpel avg_mc20: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel avg_mc02: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel avg_mc22: 2048/2048 bytes bit-exact (100.0000%)

  All 3 anchors bit-exact PASS first try.

Why anchors only in this PR: the avg_ pattern is uniform across all
16 positions (each is just "put_ result + L2 with dst").  Landing
the anchors first confirms the macro pattern works for both put_
and avg_; the remaining 13 (avg_mc10/30/01/03 + avg_mc11..33) follow
the same template in a follow-up PR.

State of the qpel matrix after this PR:
  put_ : 15 of 16 positions ✓ (mc00 is integer copy, no wrapper)
  avg_ :  3 of 16 positions ✓ (mc20, mc02, mc22 anchors)
        13 follow-up positions
2026-05-25 08:35:25 +02:00
claude-noether 0894a46114 h264: qpel diagonals — 8 positions (mc11/12/13/21/23/31/32/33)
Closes the qpel buildout.  All 8 remaining diagonal positions land
in one PR.  Each is the rounded average of two half-pel intermediates
per H.264 §8.4.2.2.1 / Table 8-4, with the decomposition matching
the FFmpeg .S reference structure (verified by reading
external/ffmpeg-snapshot/.../h264qpel_neon.S lines 622-758).

Decomposition table (the formula for each output cell at (r,c)):

  mc11 ¼¼ : avg(mc20[r,   c],   mc02[r, c])
  mc12 ¼½ : avg(mc22[r,   c],   mc02[r, c])
  mc13 ¼¾ : avg(mc20[r+1, c],   mc02[r, c])
  mc21 ½¼ : avg(mc22[r,   c],   mc20[r, c])
  mc23 ½¾ : avg(mc22[r,   c],   mc20[r+1, c])
  mc31 ¾¼ : avg(mc20[r,   c],   mc02[r, c+1])
  mc32 ¾½ : avg(mc22[r,   c],   mc02[r, c+1])
  mc33 ¾¾ : avg(mc20[r+1, c],   mc02[r, c+1])

The (r±1, c±1) offsets capture the position-dependent shift that
the FFmpeg .S encodes by pre-incrementing x1 (src pointer) before
branching into the common mc11/mc21 code paths.

Scope (tightly macro-ised):
  - 8 new kernel enums (MC11..MC33 = 23..30) → CPU.
  - 8 NEON externs for the vendored ff_put_h264_qpel8_mc*_neon.
  - 8 CPU dispatches via existing DEFINE_QPEL_CPU_DISPATCH macro.
  - 8 public dispatches via DEFINE_QPEL_DISPATCH macro.
  - 8 recipe wrappers via DEFINE_QPEL_RECIPE macro.
  - Header decls condensed via a DECLARE_QPEL_DIAG macro that
    expands to both recipe + dispatch decls per name.
  - C references via DEFINE_DIAG_REF macro: each ref is a 6-line
    wrapper around the per-cell hpel_h / hpel_v / hpel_hv helpers
    (the latter being the per-cell version of mc22's 13-row int16
    tmp[] computation).
  - Test wrapper: test_qpel_diag_all() drives all 8 through the
    existing run_quarter_axis_qpel() harness.

Verified on hertz (Pi 5 / V3D 7.1):

  $ ./build/test_api_h264 | tail -8
    H.264 qpel mc11: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc12: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc13: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc21: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc23: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc31: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc32: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc33: 2048/2048 bytes bit-exact (100.0000%)

ALL 8 diagonal positions bit-exact PASS first try.  Meaningful
because the position-dependent (r±1, c±1) source offsets are easy
to get wrong by transcription, and any of them would surface on
random inputs immediately.

After this PR the H.264 qpel 8x8 put_ matrix is complete:
  mc00 mc01 mc02 mc03
  mc10 mc11 mc12 mc13
  mc20 mc21 mc22 mc23
  mc30 mc31 mc32 mc33

15 of 16 positions exposed through the daedalus API; mc00 is just
integer copy and rarely needs a dispatch wrapper (libavcodec sets
the function pointer table directly).  mc20 retains its QPU shader
(cycle 9 / v3d_h264_qpel_mc20.spv); all other 14 are CPU NEON.

What this does NOT cover (still in backlog):
  - avg_ variants (the "add" form for biprediction, 16 more
    positions).  Currently the API only exposes put_.
  - 16x16 qpel (separate function family in FFmpeg; the 8x8 path
    can be used twice to substitute when 16x16 isn't critical).
  - QPU shaders for any qpel position other than mc20.
2026-05-25 07:49:12 +02:00
claude-noether e01f7bc7c6 h264: qpel single-axis quarter-pel — mc10/mc30/mc01/mc03 (CPU/NEON)
Closes the 4 single-axis quarter-pel positions in one PR.  Each is
a half-pel lowpass clipped to u8 followed by L2 rounded-average
with an integer-aligned source pixel per H.264 §8.4.2.2.1:

  mc10  ¼-H ("a" pos): clip255(mc20(s)) avg src[r,c]
  mc30  ¾-H ("c" pos): clip255(mc20(s)) avg src[r,c+1]
  mc01  ¼-V ("d" pos): clip255(mc02(s)) avg src[r,c]
  mc03  ¾-V ("n" pos): clip255(mc02(s)) avg src[r+1,c]

The mc10/mc30 pair and mc01/mc03 pair only differ in WHICH integer
source pixel they average with — the half-pel computation is the
same.  Putting them in one PR is justified by that uniformity.

Scope:
  - 4 new kernel enums: MC10=19, MC30=20, MC01=21, MC03=22 → CPU.
  - 4 NEON externs for the vendored ff_put_h264_qpel8_mc{10,30,01,03}_neon.
  - 4 CPU dispatch wrappers via DEFINE_QPEL_CPU_DISPATCH macro
    (collapses ~50 LOC of repetition).
  - 4 public dispatch fns via DEFINE_QPEL_DISPATCH macro.
  - 4 recipe wrappers via DEFINE_QPEL_RECIPE macro.
  - tests/h264_qpel8_quarter_axis_ref.c covers all four via shared
    hpel_h() / hpel_v() inlines + per-mode L2 average.
  - Test refactor: generic run_quarter_axis_qpel() harness exercises
    all 4 positions through a single helper (~50 LOC for 4 tests vs
    ~200 if each was hand-rolled).

Verified on hertz:

  $ ./build/test_api_h264 | tail -8
    H.264 deblock chroma h intra: 256/256 bytes bit-exact (100.0000%)
    H.264 qpel mc20: 1024/1024 bytes bit-exact (100.0000%)
    H.264 qpel mc02: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc22: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc10: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc30: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc01: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc03: 2048/2048 bytes bit-exact (100.0000%)

  All 4 new positions bit-exact PASS first try.

Coverage matrix update:
  put_  mc00 mc10 mc20 mc30
  mc01     —    ✓    —    ✓
  mc11     —    —    ✓    —     ← this row
  mc21     —    —    —    —
  mc31     —    —    —    —
  mc02     —    —    ✓    —     ← mc02 + mc22 anchor
  mc03     —    —    ✓    —

After this PR: 7 of 16 single-axis + diagonal positions done.
Remaining 9 are the off-axis quarter-pel combinations
(mc11/mc12/mc13/mc21/mc23/mc31/mc32/mc33) — each combines a 2D
lowpass intermediate with L2 averaging against a 1D-lowpass output.
Next PR scope.

Why no QPU shaders: same R-band logic as the prior CPU additions.
At ~10 ns per 8x8 NEON block, all 16 qpel positions together
would land in ~1.3 ms/frame at 1080p worst case — comfortably
inside the 33 ms budget.  QPU shader for mc20 already exists
(cycle 9 / v3d_h264_qpel_mc20.spv); the other 15 follow once a
clear perf reason emerges.
2026-05-25 01:29:52 +02:00
claude-noether 20a4299c5c h264: qpel mc22 (2D half-pel, CPU/NEON)
Adds the "j position" 2D half-pel via cascaded H + V 6-tap lowpass
with intermediate 16-bit precision per H.264 §8.4.2.2.1.  One of the
most common qpel positions in real H.264 streams — many encoders
emit 1/2-1/2 motion vectors as their best-RD choice.

Algorithmically distinct from the 1D mc20/mc02 siblings:
  - Horizontal 6-tap produces 13 rows of int16 intermediate (no
    per-stage clip/round — full precision retained).
  - Vertical 6-tap on the intermediate, then +512 >> 10 (the
    double-shift compensates for both 6-tap scalings) + clip255.

The intermediate-precision requirement means the C reference can't
just be "call mc20 then mc02" — that would double-clip and produce
the wrong result.  The 13-row int16 tmp[] buffer is the central
invariant.

Scope (same pattern as mc02 PR #15):
  - Public API: daedalus_dispatch_h264_qpel_mc22 + recipe wrapper.
  - Internal: dispatch_h264_qpel_mc22_cpu calling
    ff_put_h264_qpel8_mc22_neon.
  - Recipe table: DAEDALUS_KERNEL_H264_QPEL_MC22 = 18 → CPU.
  - C reference: tests/h264_qpel8_mc22_ref.c — explicit tmp[13][8]
    int16 staging buffer; spec-derived shifts and rounding.
  - Test: test_qpel_mc22 in test_api_h264, 8 tiles at 16×16 with
    output positioned at (SRC_ROW=3, SRC_COL=3) so the kernel's
    [-2 .. +10] read window stays in-tile.

Verified on hertz:

  $ ./build/test_api_h264 | tail -5
    H.264 deblock chroma v intra: 256/256 bytes bit-exact (100.0000%)
    H.264 deblock chroma h intra: 256/256 bytes bit-exact (100.0000%)
    H.264 qpel mc20: 1024/1024 bytes bit-exact (100.0000%)
    H.264 qpel mc02: 2048/2048 bytes bit-exact (100.0000%)
    H.264 qpel mc22: 2048/2048 bytes bit-exact (100.0000%)

  All 13 H.264 kernels in api_smoke now bit-exact PASS.

mc22 being right first try is meaningful — the +512 >> 10 scaling
+ int16 intermediate sequence has multiple sign/shift/clip pitfalls
and any of them would surface on random inputs immediately.

Coverage matrix update:
  put_ mc20 ✓ (QPU+CPU)  put_ mc02 ✓ (CPU)  put_ mc22 ✓ (CPU)
  → 12 single put_ positions still missing (¼/¾ + HV combos with
  L2 averaging).
2026-05-25 01:03:14 +02:00
claude-noether c3301b0c2e h264: qpel mc02 (vertical half-pel, CPU/NEON)
Mirror of cycle 9's mc20 transposed to vertical orientation.  Wires
up the second qpel half-pel position via the vendored
ff_put_h264_qpel8_mc02_neon symbol, closes the "missing vertical
sibling" gap that mc20 left open since cycle 9.

Scope:
  - Public API: daedalus_dispatch_h264_qpel_mc02 + recipe wrapper.
  - Internal: dispatch_h264_qpel_mc02_cpu calling the NEON entry.
  - Recipe table: DAEDALUS_KERNEL_H264_QPEL_MC02 = 17 → CPU.
    Explicit SUBSTRATE_QPU returns -1 (no shader yet).
  - C reference: tests/h264_qpel8_mc02_ref.c — vertical 6-tap
    transpose of mc20 (reads src[(r±N)*stride + c] instead of
    src[r*stride + c±N]).
  - Test: test_qpel_mc02 in test_api_h264, 8 tiles × 16×16 cols
    × 16 rows, random input, bit-exact compare against the C ref.

Verified on hertz:

  $ ./build/test_api_h264
  ...
    H.264 qpel mc20: 1024/1024 bytes bit-exact (100.0000%)
    H.264 qpel mc02: 2048/2048 bytes bit-exact (100.0000%)

  All 12 H.264 kernels in the api_smoke now bit-exact PASS.

Why CPU-only: same R-band logic as the deblock _h sibling pattern.
mc02 at ~7.6 ns per 8x8 block on NEON (per the cycle 9 baseline
measurements) gives ~700 us for 8160 MBs × 4 8x8 luma blocks at
1080p — comfortably inside the 33 ms budget.  QPU shader is a
fast-follow once the V vs H shader work is consolidated (the
transpose for the V shader is not mechanical — different SIMD
access pattern than the H shader).

Coverage matrix update:

  qpel position  put_ status  avg_ status
  -------------  -----------  -----------
  mc00 (copy)    not wired    not wired
  mc10 (¼-H)     not wired    not wired
  mc20 (½-H)    ✓ QPU+CPU     not wired
  mc30 (¾-H)     not wired    not wired
  mc01 (¼-V)     not wired    not wired
  mc02 (½-V)    ✓ CPU         not wired (this PR)
  mc03 (¾-V)     not wired    not wired
  mc11..mc33     not wired    not wired

13 more qpel positions to go for the full put_ matrix.  Adding them
follows the same template; each is a small contained PR.
2026-05-25 00:47:37 +02:00
claude-noether 9b1c106dc5 h264: deblock bS=4 intra variants (luma + chroma, V + H)
Closes the deblock matrix: adds the four bS=4 intra-strength loop
filters used at I-MB edges (and other boundaries where H.264
§8.7.2.1 forces boundary strength to 4).  After this PR fourier
covers all 8 standard 8-bit 4:2:0 deblock combinations:

    bS<4   bS=4
    -----  -----
  luma_v  ✓ (cycle 8 QPU)   ✓ (CPU)
  luma_h  ✓ (CPU, PR #9)    ✓ (CPU)
  chrm_v  ✓ (CPU, PR #10)   ✓ (CPU)
  chrm_h  ✓ (CPU, PR #10)   ✓ (CPU)

Scope:
  - 4 new kernel enums (LV_INTRA=13, LH_INTRA=14, CV_INTRA=15,
    CH_INTRA=16), all → CPU substrate in the recipe table.
  - 4 new public dispatch fns + 4 recipe wrappers (defined via two
    DEFINE_INTRA_DISPATCH / DEFINE_INTRA_RECIPE macros to keep the
    boilerplate tight).
  - 4 new extern decls for the vendored
    ff_h264_{v,h}_loop_filter_{luma,chroma}_intra_neon symbols.
  - C reference: tests/h264_intra_loop_filter_ref.c covers all four
    orientations.  Algorithm per H.264 §8.7.2.3:

      Luma: per-side strong/weak filter selector
        strong_p = (|p2-p0| < β) AND (|p0-q0| < (α>>2)+2)
        strong_q = (|q2-q0| < β) AND (|p0-q0| < (α>>2)+2)
        Strong updates p0/p1/p2 (and mirror); weak updates p0 only.
      Chroma: always weak, only p0/q0 updated.

  - daedalus_h264_deblock_meta is REUSED for intra dispatches; the
    tc0[] field is ignored (bS=4 hardcodes the strength).  Callers
    can build a single edge list and route by kernel without an
    extra struct.

  - Test refactor: an intra_test_spec table + run_intra_test helper
    drives all four orientations through one harness, keeping the
    new test surface compact (~50 LOC for 4 kernels vs ~200 if each
    had its own test_deblock_*_intra fn).

Verified on hertz (Pi 5 / V3D 7.1):

  $ ./build/test_api_h264
  === Phase 8a API smoke: H.264 kernels via recipe dispatch ===
    ...
    H.264 deblock luma v intra: 1024/1024 bytes bit-exact (100.0000%)
    H.264 deblock luma h intra: 1024/1024 bytes bit-exact (100.0000%)
    H.264 deblock chroma v intra: 256/256 bytes bit-exact (100.0000%)
    H.264 deblock chroma h intra: 256/256 bytes bit-exact (100.0000%)
    ...

  All 11 H.264 kernels bit-exact PASS — the deblock matrix is closed.

The bit-exact match on first try is meaningful for these kernels:
the strong/weak filter selector + per-side asymmetry would have
surfaced any sign / shift / rounding mistake immediately.  The
C reference is now a usable spec checkpoint for the eventual QPU
shader work.

QPU shader follow-up: not in this PR.  The intra path's 3-cell
per-side update + strong/weak branch is structurally more complex
than the bS<4 path that already has a V shader (v3d_h264deblock.spv).
Per the prior R-band logic for deblock, intra edges are < 20% of
total deblock work at typical bit-rates, so NEON-only at ~ 10 ns/edge
fits comfortably in the budget.
2026-05-25 00:00:46 +02:00
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
claude-noether 9d5451e0fe h264: deblock_luma_h — CPU/NEON via vendored ff_h264_h_loop_filter
Adds the horizontal-edge sibling of cycle 8's deblock_luma_v.  The
vendored FFmpeg snapshot already includes ff_h264_h_loop_filter_luma_neon
in libavcodec/aarch64/h264dsp_neon.S — this PR wires up the symbol,
the bit-exact reference, and the recipe-table entry so daedalus-decoder
and other consumers can call the H variant through the same dispatch
shape they use for _v.

Scope:
  - Public API: daedalus_dispatch_h264_deblock_luma_h(ctx, sub, ...)
    + daedalus_recipe_dispatch_h264_deblock_luma_h(ctx, ...) wrapper.
  - Internal: dispatch_h264_deblock_h_cpu() calls the NEON entry.
  - Recipe table: new DAEDALUS_KERNEL_H264_DEBLOCK_LH = 10, mapped
    to DAEDALUS_SUBSTRATE_CPU until a QPU shader is written.  An
    explicit SUBSTRATE_QPU request on the H dispatch returns -1
    (fails fast, no silent CPU degradation).
  - C reference: tests/h264_h_loop_filter_luma_ref.c — the
    column-axis transpose of h264_deblock_ref.c.  Same per-segment
    kernel; pix[-4..+3] accesses cols instead of rows*stride.
  - Test: test_api_h264 grows a test_deblock_h() with 8 tiles
    (8 cols x 16 rows each, edge at col 4), random alpha/beta/tc0;
    compares NEON dispatch against reference byte-for-byte.

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)
    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 qpel mc20: 1024/1024 bytes bit-exact (100.0000%)

  All 5 kernels bit-exact PASS.  The new H variant joins the suite
  with 1024 random-input bytes per tile x 8 tiles.

Why CPU-only for now: the daedalus-decoder downstream needs the H
edge dispatched somewhere — even at CPU NEON cost (~6 ns/edge per
the cycle 8 M3 baseline) a frame's worth at 1080p is
~ 8160 MBs * 4 edges = 32 640 edges = ~200 us — well inside the
30 fps budget.  Writing the V3D H-edge shader is a follow-up
(would be cycle 8' or similar; the V-edge shader's transpose isn't
mechanical because of how the workgroup organisation maps to columns
vs rows).

Backlog addition (out of scope for this PR):
  - V3D shader for the H variant (mirror of v3d_h264deblock.spv).
  - bS=4 intra-strength filter (different algebra; both _v and _h).
  - Chroma deblock luma_v/_h (8-cell variants).
2026-05-24 23:28:56 +02:00
claude-noether 8fdef27a7d Phase 8c: H.264 luma qpel mc20 through public API
Extends daedalus-fourier with daedalus_recipe_dispatch_h264_qpel_mc20
so libavcodec.so can route H264QpelContext.put_h264_qpel_pixels_tab[1][2]
through the recipe layer instead of ff_put_h264_qpel8_mc20_neon directly.

API additions (header + library):
  - daedalus_h264_qpel_meta { dst_off, src_off }
  - daedalus_dispatch_h264_qpel_mc20(ctx, sub, dst, src, stride,
                                     n_blocks, meta)
  - daedalus_recipe_dispatch_h264_qpel_mc20(...)  (AUTO wrapper)
  - DAEDALUS_KERNEL_H264_QPEL_MC20 = 9 in the recipe-query enum
  - daedalus_recipe_substrate_for() returns CPU NEON for cycle 9

The 6-tap horizontal half-pel filter signature matches FFmpeg's
H264QpelContext convention exactly: dst and src share a single stride
and src already points at output column 0 (filter reads cols -2..+3).
Single-stride API to make the marfrit-packages FFmpeg shim a
straight pointer-pass; no buffer rearrangement.

Verdict per docs/k9_h264qpel_mc20.md: CPU NEON.  Per-block 7.6 ns
gives 135x margin over 30 fps 1080p; QPU dispatch floor at ~250 ns
makes any V3D shader strictly worse.  Recipe table reflects that —
the recipe_dispatch entry is a one-line forward to the CPU path.

CMakeLists changes:
  - h264qpel_neon.S added to the daedalus_core static lib (only the
    bench targets owned it before; now the public API needs it too)
  - tests/h264_qpel8_mc20_ref.c added to the test_api_h264 target

Phase 8a/8b smoke gains a 4th case (test_qpel_mc20): 1024/1024
bytes bit-exact via daedalus_recipe_dispatch_h264_qpel_mc20.

Refs reauktion/daedalus-v4l2#11 — substitution arc step 2 cycle 9.
2026-05-23 03:25:24 +02:00
marfrit af8146a2cd Phase 8a: H.264 kernels through public API
Extends include/daedalus.h with cycles 6, 7, 8 (H.264 IDCT 4x4,
IDCT 8x8, luma deblock luma-v). All recipe-substrate = CPU
(matches per-cycle Phase 7 verdicts).

src/daedalus_core.c: NEON-path implementations + recipe routing.
daedalus_core library now links the full FFmpeg H.264 NEON
snapshot (h264idct + h264dsp) plus existing VP9 + dav1d.

tests/test_api_h264.c: smoke test covering all 3 H.264 kernels
via daedalus_recipe_dispatch_*. All pass 2048/2048 bit-exact.

Public API coverage after this commit:
- Cycles 1 IDCT 8x8 + 2 LPF4 + 4 LPF8: CPU+QPU+AUTO dispatch
  (test_api_idct, test_api_lpf, both pass)
- Cycle 3 MC 8h: CPU only (QPU dispatch stub returns -1)
- Cycle 5 CDEF: CPU only (QPU stub)
- Cycle 6 H.264 IDCT 4x4: CPU only (recipe + only NEON wired)
- Cycle 7 H.264 IDCT 8x8: CPU only
- Cycle 8 H.264 deblock: CPU only (QPU opportunistic — not wired
  through API yet; bench_v3d_h264deblock exists for direct test)

Next Phase 8 sub-step: wire opportunistic QPU dispatch for cycles
3+5+8 through the API (so override-mode users can request QPU).
Then surface V4L2-wrapper architecture decisions to user.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-18 14:46:03 +00:00
marfrit 1085c5699c Phase 8: wire IDCT QPU dispatch through public API
daedalus_ctx now owns a v3d_runner when V3D is available. The
public API's dispatch_vp9_idct8 routes QPU calls through a
new dispatch_idct8_qpu helper that: (1) lazy-creates the cycle 1
v4 pipeline on first use, (2) allocates 3 host-visible SSBOs
per call (coeffs/dst/meta), (3) memcpy host->GPU, (4) dispatch
with the v4 32-blocks-per-WG geometry, (5) memcpy GPU->host.

Per-call alloc is intentional for Phase 8 correctness-first
scope; buffer-pool perf optimization is deferred.

Added daedalus_ctx_create_no_qpu() for fast-path callers that
know they want CPU only.

test_api_idct extended to a 3-mode matrix: CPU forced, QPU
forced, AUTO recipe. All three deliver 4096/4096 bit-exact
on hertz with V3D 7.1.7.0:

  recipe substrate for VP9_IDCT8: 2 (QPU)
  [CPU] 4096/4096 bit-exact
  [QPU] 4096/4096 bit-exact (real QPU dispatch through the API)
  [AUTO] 4096/4096 bit-exact (recipe routes to QPU)

Next Phase 8 sub-step: same wiring pattern for cycle 2 LPF wd=4
and cycle 4 LPF wd=8 (the other two recipe-QPU kernels).
Cycle 3 MC and cycle 5 CDEF only need the dispatch hook
(recipe routes to CPU; QPU stays opportunistic via explicit
override).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-18 13:55:55 +00:00
marfrit 760f6a4060 Phase 8 skeleton: public C API + first end-to-end smoke test
include/daedalus.h: stable C API surface exposing the 5 cycles
(VP9 IDCT 8x8, LPF wd=4, MC 8h, LPF wd=8; AV1 CDEF). Per-kernel
recipe-dispatch helpers default to the cycle 1-5 verdict
substrate (QPU for cycles 1+2+4, CPU for cycles 3+5); explicit
override available for benchmarking and runtime-aware scheduling.

src/daedalus_core.c: NEON-path implementation of all 5 kernels
wrapped behind the public API. QPU path stubbed out (returns -1)
since wiring v3d_runner into daedalus_ctx is the next Phase 8
sub-step; with has_qpu=0 the recipe falls back to CPU cleanly.

tests/test_api_idct.c: 64-block IDCT through the public recipe
dispatch, bit-exact vs C ref. PASS 4096/4096 bytes — proves the
API surface compiles, library links, dispatch routing works, and
NEON fallback delivers correct results.

docs/phase8_scoping.md: architecture options (A=userspace V4L2,
B=kernel V4L2 shim, C=direct libva); pick A for v1; explicitly
out-of-scope work tracked.

Next Phase 8 sub-step: wire v3d_runner into daedalus_ctx so
has_qpu=1 and QPU dispatch goes through the API too. After that:
V4L2 ioctl glue, bitstream parser, superblock loop.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-18 13:54:43 +00:00