1 files changed, 85 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jxl/render_pipeline/stage_ycbcr.cc b/third_party/jpeg-xl/lib/jxl/render_pipeline/stage_ycbcr.cc
new file mode 100644
index 0000000000..5cba4a7d41
--- /dev/null
+++ b/third_party/jpeg-xl/lib/jxl/render_pipeline/stage_ycbcr.cc
@@ -0,0 +1,85 @@
+// 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()) {}
+
+  void 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 {
+    PROFILER_ZONE("UndoYCbCr");
+
+    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);
+    }
+  }
+
+  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