stage_ycbcr.cc - mozsearch

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// Copyright (c) the JPEG XL Project Authors. All rights reserved.

//

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

#include "lib/jxl/render_pipeline/stage_ycbcr.h"

#undef HWY_TARGET_INCLUDE

#define HWY_TARGET_INCLUDE "lib/jxl/render_pipeline/stage_ycbcr.cc"

#include <hwy/foreach_target.h>

#include <hwy/highway.h>

HWY_BEFORE_NAMESPACE();

namespace jxl {

namespace HWY_NAMESPACE {

// These templates are not found via ADL.

using hwy::HWY_NAMESPACE::Add;

using hwy::HWY_NAMESPACE::MulAdd;

class kYCbCrStage : public RenderPipelineStage {

 public:

  kYCbCrStage() : RenderPipelineStage(RenderPipelineStage::Settings()) {}

  Status ProcessRow(const RowInfo& input_rows, const RowInfo& output_rows,

                    size_t xextra, size_t xsize, size_t xpos, size_t ypos,

                    size_t thread_id) const final {

    const HWY_FULL(float) df;

    // Full-range BT.601 as defined by JFIF Clause 7:

    // https://www.itu.int/rec/T-REC-T.871-201105-I/en

    const auto c128 = Set(df, 128.0f / 255);

    const auto crcr = Set(df, 1.402f);

    const auto cgcb = Set(df, -0.114f * 1.772f / 0.587f);

    const auto cgcr = Set(df, -0.299f * 1.402f / 0.587f);

    const auto cbcb = Set(df, 1.772f);

    float* JXL_RESTRICT row0 = GetInputRow(input_rows, 0, 0);

    float* JXL_RESTRICT row1 = GetInputRow(input_rows, 1, 0);

    float* JXL_RESTRICT row2 = GetInputRow(input_rows, 2, 0);

    // TODO(eustas): when using frame origin, addresses might be unaligned;

    //               making them aligned will void performance penalty.

    for (size_t x = 0; x < xsize; x += Lanes(df)) {

      const auto y_vec = Add(LoadU(df, row1 + x), c128);

      const auto cb_vec = LoadU(df, row0 + x);

      const auto cr_vec = LoadU(df, row2 + x);

      const auto r_vec = MulAdd(crcr, cr_vec, y_vec);

      const auto g_vec = MulAdd(cgcr, cr_vec, MulAdd(cgcb, cb_vec, y_vec));

      const auto b_vec = MulAdd(cbcb, cb_vec, y_vec);

      StoreU(r_vec, df, row0 + x);

      StoreU(g_vec, df, row1 + x);

      StoreU(b_vec, df, row2 + x);

    return true;

  RenderPipelineChannelMode GetChannelMode(size_t c) const final {

    return c < 3 ? RenderPipelineChannelMode::kInPlace

                 : RenderPipelineChannelMode::kIgnored;

  const char* GetName() const override { return "YCbCr"; }

};

std::unique_ptr<RenderPipelineStage> GetYCbCrStage() {

  return jxl::make_unique<kYCbCrStage>();

// NOLINTNEXTLINE(google-readability-namespace-comments)

}  // namespace HWY_NAMESPACE

}  // namespace jxl

HWY_AFTER_NAMESPACE();

#if HWY_ONCE

namespace jxl {

HWY_EXPORT(GetYCbCrStage);

std::unique_ptr<RenderPipelineStage> GetYCbCrStage() {

  return HWY_DYNAMIC_DISPATCH(GetYCbCrStage)();

}  // namespace jxl

#endif