claude-noether
e3c28495ae
mc10 (¼-H), mc30 (¾-H), mc01 (¼-V), mc03 (¾-V). Each is the
corresponding half-pel filter (mc20 or mc02) with one extra L2
rounded-average step against an integer-source pixel at the tail:
mc10[r,c] = avg(clip255(mc20(s)), s[r, c ])
mc30[r,c] = avg(clip255(mc20(s)), s[r, c+1])
mc01[r,c] = avg(clip255(mc02(s)), s[r, c ])
mc03[r,c] = avg(clip255(mc02(s)), s[r+1, c ])
Each shader is ~45 lines (mc20-/mc02-pattern + 1 L2 line).
CMake foreach loop generates the 4 SPV compile rules. Dispatch
helper `dispatch_h264_qpel_axis_qpu` shares plumbing across all 4
(axis flag selects src_max bounds: H reads cols -2..+10, V reads
rows -2..+10). DEFINE_QPEL_AXIS_QPU + DEFINE_QPEL_DISPATCH_QPU
macros collapse ~200 LOC of boilerplate.
Recipe table flips DAEDALUS_KERNEL_H264_QPEL_MC{10,30,01,03} from
CPU to QPU.
Verified on hertz:
$ ./build/test_api_h264 | grep "qpel mc[01230]"
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%)
(+ mc20/mc02/mc22 anchors from previous PRs)
Qpel QPU coverage:
put_ mc20 ✓ mc02 ✓ mc22 ✓ (3 anchors)
mc10 ✓ mc30 ✓ mc01 ✓ mc03 ✓ (4 quarter-axis, THIS PR)
mc11/12/13/21/23/31/32/33 — CPU NEON (8 diagonals)
avg_ all 15 positions — CPU NEON
7 of 15 useful put_ positions now on QPU. The 8 diagonals each
compose two half-pel results via L2; can land via dedicated kernels
or by chaining existing anchor dispatches (the latter would need
the L2 step as a fourth dispatch — probably cheaper to write
dedicated 8x diagonal shaders).
48 lines
1.7 KiB
Plaintext
48 lines
1.7 KiB
Plaintext
// daedalus-fourier — H.264 luma qpel mc10 (8x8, ¼-pel horizontal),
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// V3D 7.1. Per H.264 §8.4.2.2.1 "a" position:
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//
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// dst[r,c] = ((clip255(mc20(s)[r,c]) + s[r,c] + 1) >> 1)
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//
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// = horizontal half-pel filter, clipped to u8, then L2 rounded-averaged
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// with the integer source pixel at the SAME position. Sibling of
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// v3d_h264_qpel_mc20.comp with the L2 step added at the tail.
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//
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// License: BSD-2-Clause.
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#version 450
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#extension GL_EXT_shader_8bit_storage : require
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#extension GL_EXT_shader_explicit_arithmetic_types : require
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layout(local_size_x = 64, local_size_y = 1, local_size_z = 1) in;
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layout(binding = 0) readonly buffer Src { uint8_t src[]; } u_src;
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layout(binding = 1) buffer Dst { uint8_t dst[]; } u_dst;
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layout(binding = 2) readonly buffer Meta { uvec4 meta[]; } u_meta;
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layout(push_constant) uniform PC { uint n_blocks, stride_u8, _p0, _p1; } pc;
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void main()
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{
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uint block_idx = gl_WorkGroupID.x;
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if (block_idx >= pc.n_blocks) return;
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uint lane = gl_LocalInvocationID.x;
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uint r = lane >> 3, c = lane & 7u;
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uint dst_off = u_meta.meta[block_idx].x;
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uint src_off = u_meta.meta[block_idx].y;
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uint stride = pc.stride_u8;
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uint row_base = src_off + r * stride + c;
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int s_m2 = int(u_src.src[row_base - 2u]);
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int s_m1 = int(u_src.src[row_base - 1u]);
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int s_0 = int(u_src.src[row_base ]);
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int s_p1 = int(u_src.src[row_base + 1u]);
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int s_p2 = int(u_src.src[row_base + 2u]);
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int s_p3 = int(u_src.src[row_base + 3u]);
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int v = s_m2 - 5 * s_m1 + 20 * s_0 + 20 * s_p1 - 5 * s_p2 + s_p3 + 16;
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int hp = clamp(v >> 5, 0, 255);
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// L2 average with the integer source at the SAME (r, c) position.
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int avg = (hp + s_0 + 1) >> 1;
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u_dst.dst[dst_off + r * stride + c] = uint8_t(avg);
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}
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