Video Color Managament

cc/output/color_lut_cache.cc

+// Copyright 2016 The Chromium 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 "cc/output/color_lut_cache.h"
+
+#include <stdint.h>
+#include <vector>
+
+#include "gpu/command_buffer/client/gles2_interface.h"
+#include "third_party/qcms/src/qcms.h"
+
+#ifndef THIS_MUST_BE_INCLUDED_AFTER_QCMS_H
+extern "C" {
+#include "third_party/qcms/src/chain.h"
+};
+#endif
+
+// After a LUT has not been used for this many frames, we release it.
+const uint32_t kMaxFramesUnused = 10;
+
+ColorLUTCache::ColorLUTCache(gpu::gles2::GLES2Interface* gl)
+    : lut_cache_(0), gl_(gl) {}
+
+ColorLUTCache::~ColorLUTCache() {
+  GLuint textures[10];
+  size_t n = 0;
+  for (const auto& cache_entry : lut_cache_) {
+    textures[n++] = cache_entry.second.first;
+    if (n == arraysize(textures)) {
+      gl_->DeleteTextures(n, textures);
+      n = 0;
+    }
+  }
+  if (n)
+    gl_->DeleteTextures(n, textures);
+}
+
+namespace {
+
+// QCMS is trixy, it has a datatype called qcms_CIE_xyY, but what it expects
+// is in fact not xyY color coordinates, it just wants the x/y values of the
+// primaries with Y equal to 1.0.
+qcms_CIE_xyY xyfromXY(const media::VideoColorSpace::XY& xy) {
+  qcms_CIE_xyY ret;
+  ret.x = xy.first;
+  ret.y = xy.second;
+  ret.Y = 1.0f;
+  return ret;
+}
+
+}  // namespace
+
+unsigned int ColorLUTCache::MakeLUT(const media::VideoColorSpace& from,
+                                    const gfx::ColorSpace& to,
+                                    int lut_samples) {
+  media::VideoColorSpace intermediate = media::VideoColorSpace::XYZ();
+  media::ColorTransform from_transform(from, intermediate,
+                                       media::ColorTransform::INTENT_PERCEIVED);
+
+  std::vector<media::VideoColorSpace::XY> primaries =
+      intermediate.GetPrimaries();
+  qcms_CIE_xyYTRIPLE rgb;
+  qcms_CIE_xyY w;
+  rgb.red = xyfromXY(primaries[0]);
+  rgb.green = xyfromXY(primaries[1]);
+  rgb.blue = xyfromXY(primaries[2]);
+  w = xyfromXY(primaries[3]);
+  qcms_profile* in = qcms_profile_create_rgb_with_gamma(w, rgb, 1.0f);
+
+  const std::vector<char>& icc_data = to.GetICCProfile();
+  qcms_profile* out;
+  if (icc_data.empty()) {
+    out = qcms_profile_sRGB();
+  } else {
+    out = qcms_profile_from_memory(icc_data.data(), icc_data.size());
+  }
+
+  int lut_entries = lut_samples * lut_samples * lut_samples;
+  float inverse = 1.0f / (lut_samples - 1);
+  std::vector<float> xyz_tmp(lut_entries * 3);
+  int pos = 0;
+  for (int a = 0; a < lut_samples; a++) {
+    for (int b = 0; b < lut_samples; b++) {
+      for (int c = 0; c < lut_samples; c++) {
+        media::VideoColorSpace::TriStim tmp;
+        tmp.values[0] = a * inverse;
+        tmp.values[2] = b * inverse;
+        tmp.values[1] = c * inverse;
+        from_transform.transform(&tmp, 1);
+        xyz_tmp[pos++] = fmax(0.0f, fmin(1.0f, tmp.values[0]));
+        xyz_tmp[pos++] = fmax(0.0f, fmin(1.0f, tmp.values[1]));
+        xyz_tmp[pos++] = fmax(0.0f, fmin(1.0f, tmp.values[2]));
+      }
+    }
+  }
+  qcms_chain_transform(in, out, xyz_tmp.data(), xyz_tmp.data(),
+                       lut_entries * 3);
+  qcms_profile_release(in);
+  qcms_profile_release(out);
+
+  std::vector<unsigned char> lut(lut_samples * lut_samples * lut_samples * 4);
+  unsigned char* lutp = lut.data();
+  pos = 0;
+  for (int i = 0; i < lut_entries; i++) {
+    for (int channel = 0; channel < 3; channel++) {
+      int v = (int)floorf(xyz_tmp[pos++] * 255.0 + 0.5);
+      *(lutp++) = v < 0 ? 0 : v > 255 ? 255 : v;
+    }
+    *(lutp++) = 255;
+  }
+
+  unsigned int lut_texture;
+  gl_->GenTextures(1, &lut_texture);
+  gl_->BindTexture(GL_TEXTURE_2D, lut_texture);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  gl_->TexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, lut_samples,
+                  lut_samples * lut_samples, 0, GL_RGBA, GL_UNSIGNED_BYTE,
+                  lut.data());
+  return lut_texture;
+}
+
+unsigned int ColorLUTCache::GetLUT(const media::VideoColorSpace& from,
+                                   const gfx::ColorSpace& to,
+                                   int lut_samples) {
+  CacheKey key(from, std::make_pair(to, lut_samples));
+  auto iter = lut_cache_.Get(key);
+  if (iter != lut_cache_.end()) {
+    iter->second.second = current_frame_;
+    return iter->second.first;
+  }
+
+  unsigned int lut = MakeLUT(from, to, lut_samples);
+  lut_cache_.Put(key, std::make_pair(lut, current_frame_));
+  return lut;
+}
+
+void ColorLUTCache::Swap() {
+  current_frame_++;
+  while (!lut_cache_.empty() &&
+         current_frame_ - lut_cache_.rbegin()->second.first >
+             kMaxFramesUnused) {
+    gl_->DeleteTextures(1, &lut_cache_.rbegin()->second.first);
+    lut_cache_.ShrinkToSize(lut_cache_.size() - 1);
+  }
+}