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#pragma once
// Packed YUV 4:2:2 (YUYV / YVYU / UYVY / VYUY): two pixels per 32-bit
// word, one shared chroma pair. The Layout uses two C::Y entries plus
// one each of C::U / C::V; we resolve the duplicate Y via
// find_pos<C::Y>(n).
#include <array>
#include "../layout.h"
#include "detail.h"
namespace pixpat
{
template <typename L>
struct PackedYUVSource {
using Layout = L;
using Pixel = YUV16;
static_assert(L::kind == ColorKind::YUV);
static_assert(L::num_planes == 1);
static_assert(L::h_sub == 2 && L::v_sub == 1);
using P = typename L::template plane<0>;
static constexpr size_t y0_idx = P::template find_pos<C::Y>(0);
static constexpr size_t y1_idx = P::template find_pos<C::Y>(1);
static constexpr size_t u_idx = P::template find_pos<C::U>();
static constexpr size_t v_idx = P::template find_pos<C::V>();
static YUV16 read(const Buffer<1>& buf, size_t x, size_t y,
[[maybe_unused]] size_t W,
[[maybe_unused]] size_t H) noexcept
{
const uint8_t* p = buf.data[0] + y * buf.stride[0]
+ (x / 2) * P::bytes_per_pixel;
const auto vals = P::unpack(detail::load_word<P>(p));
const size_t y_pick = (x & 1) ? y1_idx : y0_idx;
// Both Y components share the same bit width, so the bit-width
// for y0 and y1 is identical — pick either.
return YUV16{
detail::decode_norm(P::comps[y0_idx].bits, vals[y_pick]),
detail::decode_norm(P::comps[u_idx].bits, vals[u_idx]),
detail::decode_norm(P::comps[v_idx].bits, vals[v_idx]),
uint16_t(0),
};
}
};
template <typename L>
struct PackedYUVSink {
using Layout = L;
using Pixel = YUV16;
static_assert(L::kind == ColorKind::YUV);
static_assert(L::num_planes == 1);
static_assert(L::h_sub == 2 && L::v_sub == 1);
using P = typename L::template plane<0>;
static constexpr size_t y0_idx = P::template find_pos<C::Y>(0);
static constexpr size_t y1_idx = P::template find_pos<C::Y>(1);
static constexpr size_t u_idx = P::template find_pos<C::U>();
static constexpr size_t v_idx = P::template find_pos<C::V>();
static constexpr size_t block_h = 1;
static constexpr size_t block_w = 2;
static void write_block(Buffer<1>& buf, size_t bx, size_t by,
const YUV16 (&block)[1][2]) noexcept
{
std::array<uint16_t, P::num_comps> v{};
v[y0_idx] = detail::encode_norm(P::comps[y0_idx].bits, block[0][0].y);
v[y1_idx] = detail::encode_norm(P::comps[y1_idx].bits, block[0][1].y);
// Integer chroma averaging in normalized-16 space. Truncates
// (no round-half-up).
v[u_idx] = detail::encode_norm(P::comps[u_idx].bits, uint16_t(
(uint32_t(block[0][0].u) +
uint32_t(block[0][1].u)) / 2));
v[v_idx] = detail::encode_norm(P::comps[v_idx].bits, uint16_t(
(uint32_t(block[0][0].v) +
uint32_t(block[0][1].v)) / 2));
uint8_t* p = buf.data[0] + by * buf.stride[0]
+ (bx / 2) * P::bytes_per_pixel;
detail::store_word<P>(p, P::pack(v));
}
};
} // namespace pixpat
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