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/*
* Copyright (c) 2018 The WebRTC 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 in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_tools/frame_analyzer/video_color_aligner.h"
#include <stddef.h>
#include <algorithm>
#include <cmath>
#include <cstdint>
#include <vector>
#include "api/array_view.h"
#include "api/make_ref_counted.h"
#include "api/video/i420_buffer.h"
#include "rtc_base/checks.h"
#include "rtc_tools/frame_analyzer/linear_least_squares.h"
#include "third_party/libyuv/include/libyuv/planar_functions.h"
#include "third_party/libyuv/include/libyuv/scale.h"
namespace webrtc {
namespace test {
namespace {
// Helper function for AdjustColors(). This functions calculates a single output
// row for y with the given color coefficients. The u/v channels are assumed to
// be subsampled by a factor of 2, which is the case of I420.
void CalculateYChannel(rtc::ArrayView<const uint8_t> y_data,
rtc::ArrayView<const uint8_t> u_data,
rtc::ArrayView<const uint8_t> v_data,
const std::array<float, 4>& coeff,
rtc::ArrayView<uint8_t> output) {
RTC_CHECK_EQ(y_data.size(), output.size());
// Each u/v element represents two y elements. Make sure we have enough to
// cover the Y values.
RTC_CHECK_GE(u_data.size() * 2, y_data.size());
RTC_CHECK_GE(v_data.size() * 2, y_data.size());
// Do two pixels at a time since u/v are subsampled.
for (size_t i = 0; i * 2 < y_data.size() - 1; ++i) {
const float uv_contribution =
coeff[1] * u_data[i] + coeff[2] * v_data[i] + coeff[3];
const float val0 = coeff[0] * y_data[i * 2 + 0] + uv_contribution;
const float val1 = coeff[0] * y_data[i * 2 + 1] + uv_contribution;
// Clamp result to a byte.
output[i * 2 + 0] = static_cast<uint8_t>(
std::round(std::max(0.0f, std::min(val0, 255.0f))));
output[i * 2 + 1] = static_cast<uint8_t>(
std::round(std::max(0.0f, std::min(val1, 255.0f))));
}
// Handle the last pixel for odd widths.
if (y_data.size() % 2 == 1) {
const float val = coeff[0] * y_data[y_data.size() - 1] +
coeff[1] * u_data[(y_data.size() - 1) / 2] +
coeff[2] * v_data[(y_data.size() - 1) / 2] + coeff[3];
output[y_data.size() - 1] =
static_cast<uint8_t>(std::round(std::max(0.0f, std::min(val, 255.0f))));
}
}
// Helper function for AdjustColors(). This functions calculates a single output
// row for either u or v, with the given color coefficients. Y, U, and V are
// assumed to be the same size, i.e. no subsampling.
void CalculateUVChannel(rtc::ArrayView<const uint8_t> y_data,
rtc::ArrayView<const uint8_t> u_data,
rtc::ArrayView<const uint8_t> v_data,
const std::array<float, 4>& coeff,
rtc::ArrayView<uint8_t> output) {
RTC_CHECK_EQ(y_data.size(), u_data.size());
RTC_CHECK_EQ(y_data.size(), v_data.size());
RTC_CHECK_EQ(y_data.size(), output.size());
for (size_t x = 0; x < y_data.size(); ++x) {
const float val = coeff[0] * y_data[x] + coeff[1] * u_data[x] +
coeff[2] * v_data[x] + coeff[3];
// Clamp result to a byte.
output[x] =
static_cast<uint8_t>(std::round(std::max(0.0f, std::min(val, 255.0f))));
}
}
// Convert a frame to four vectors consisting of [y, u, v, 1].
std::vector<std::vector<uint8_t>> FlattenYuvData(
const rtc::scoped_refptr<I420BufferInterface>& frame) {
std::vector<std::vector<uint8_t>> result(
4, std::vector<uint8_t>(frame->ChromaWidth() * frame->ChromaHeight()));
// Downscale the Y plane so that all YUV planes are the same size.
libyuv::ScalePlane(frame->DataY(), frame->StrideY(), frame->width(),
frame->height(), result[0].data(), frame->ChromaWidth(),
frame->ChromaWidth(), frame->ChromaHeight(),
libyuv::kFilterBox);
libyuv::CopyPlane(frame->DataU(), frame->StrideU(), result[1].data(),
frame->ChromaWidth(), frame->ChromaWidth(),
frame->ChromaHeight());
libyuv::CopyPlane(frame->DataV(), frame->StrideV(), result[2].data(),
frame->ChromaWidth(), frame->ChromaWidth(),
frame->ChromaHeight());
std::fill(result[3].begin(), result[3].end(), 1u);
return result;
}
ColorTransformationMatrix VectorToColorMatrix(
const std::vector<std::vector<double>>& v) {
ColorTransformationMatrix color_transformation;
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 4; ++j)
color_transformation[i][j] = v[i][j];
}
return color_transformation;
}
} // namespace
ColorTransformationMatrix CalculateColorTransformationMatrix(
const rtc::scoped_refptr<I420BufferInterface>& reference_frame,
const rtc::scoped_refptr<I420BufferInterface>& test_frame) {
IncrementalLinearLeastSquares incremental_lls;
incremental_lls.AddObservations(FlattenYuvData(test_frame),
FlattenYuvData(reference_frame));
return VectorToColorMatrix(incremental_lls.GetBestSolution());
}
ColorTransformationMatrix CalculateColorTransformationMatrix(
const rtc::scoped_refptr<Video>& reference_video,
const rtc::scoped_refptr<Video>& test_video) {
RTC_CHECK_GE(reference_video->number_of_frames(),
test_video->number_of_frames());
IncrementalLinearLeastSquares incremental_lls;
for (size_t i = 0; i < test_video->number_of_frames(); ++i) {
incremental_lls.AddObservations(
FlattenYuvData(test_video->GetFrame(i)),
FlattenYuvData(reference_video->GetFrame(i)));
}
return VectorToColorMatrix(incremental_lls.GetBestSolution());
}
rtc::scoped_refptr<Video> AdjustColors(
const ColorTransformationMatrix& color_transformation,
const rtc::scoped_refptr<Video>& video) {
class ColorAdjustedVideo : public Video {
public:
ColorAdjustedVideo(const ColorTransformationMatrix& color_transformation,
const rtc::scoped_refptr<Video>& video)
: color_transformation_(color_transformation), video_(video) {}
int width() const override { return video_->width(); }
int height() const override { return video_->height(); }
size_t number_of_frames() const override {
return video_->number_of_frames();
}
rtc::scoped_refptr<I420BufferInterface> GetFrame(
size_t index) const override {
return AdjustColors(color_transformation_, video_->GetFrame(index));
}
private:
const ColorTransformationMatrix color_transformation_;
const rtc::scoped_refptr<Video> video_;
};
return rtc::make_ref_counted<ColorAdjustedVideo>(color_transformation, video);
}
rtc::scoped_refptr<I420BufferInterface> AdjustColors(
const ColorTransformationMatrix& color_matrix,
const rtc::scoped_refptr<I420BufferInterface>& frame) {
// Allocate I420 buffer that will hold the color adjusted frame.
rtc::scoped_refptr<I420Buffer> adjusted_frame =
I420Buffer::Create(frame->width(), frame->height());
// Create a downscaled Y plane with the same size as the U/V planes to
// simplify converting the U/V planes.
std::vector<uint8_t> downscaled_y_plane(frame->ChromaWidth() *
frame->ChromaHeight());
libyuv::ScalePlane(frame->DataY(), frame->StrideY(), frame->width(),
frame->height(), downscaled_y_plane.data(),
frame->ChromaWidth(), frame->ChromaWidth(),
frame->ChromaHeight(), libyuv::kFilterBox);
// Fill in the adjusted data row by row.
for (int y = 0; y < frame->height(); ++y) {
const int half_y = y / 2;
rtc::ArrayView<const uint8_t> y_row(frame->DataY() + frame->StrideY() * y,
frame->width());
rtc::ArrayView<const uint8_t> u_row(
frame->DataU() + frame->StrideU() * half_y, frame->ChromaWidth());
rtc::ArrayView<const uint8_t> v_row(
frame->DataV() + frame->StrideV() * half_y, frame->ChromaWidth());
rtc::ArrayView<uint8_t> output_y_row(
adjusted_frame->MutableDataY() + adjusted_frame->StrideY() * y,
frame->width());
CalculateYChannel(y_row, u_row, v_row, color_matrix[0], output_y_row);
// Chroma channels only exist every second row for I420.
if (y % 2 == 0) {
rtc::ArrayView<const uint8_t> downscaled_y_row(
downscaled_y_plane.data() + frame->ChromaWidth() * half_y,
frame->ChromaWidth());
rtc::ArrayView<uint8_t> output_u_row(
adjusted_frame->MutableDataU() + adjusted_frame->StrideU() * half_y,
frame->ChromaWidth());
rtc::ArrayView<uint8_t> output_v_row(
adjusted_frame->MutableDataV() + adjusted_frame->StrideV() * half_y,
frame->ChromaWidth());
CalculateUVChannel(downscaled_y_row, u_row, v_row, color_matrix[1],
output_u_row);
CalculateUVChannel(downscaled_y_row, u_row, v_row, color_matrix[2],
output_v_row);
}
}
return adjusted_frame;
}
} // namespace test
} // namespace webrtc
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