diff --git a/rtc_tools/BUILD.gn b/rtc_tools/BUILD.gn
index c0716b4dac..3d9804c613 100644
--- a/rtc_tools/BUILD.gn
+++ b/rtc_tools/BUILD.gn
@@ -86,6 +86,10 @@ rtc_static_library("video_file_writer") {
 
 rtc_static_library("video_quality_analysis") {
   sources = [
+    "frame_analyzer/linear_least_squares.cc",
+    "frame_analyzer/linear_least_squares.h",
+    "frame_analyzer/video_color_aligner.cc",
+    "frame_analyzer/video_color_aligner.h",
     "frame_analyzer/video_quality_analysis.cc",
     "frame_analyzer/video_quality_analysis.h",
     "frame_analyzer/video_temporal_aligner.cc",
@@ -93,6 +97,7 @@ rtc_static_library("video_quality_analysis") {
   ]
   deps = [
     ":video_file_reader",
+    "../api:array_view",
     "../api/video:video_frame_i420",
     "../common_video",
     "../rtc_base:checks",
@@ -333,7 +338,9 @@ if (rtc_include_tests) {
     testonly = true
 
     sources = [
+      "frame_analyzer/linear_least_squares_unittest.cc",
       "frame_analyzer/reference_less_video_analysis_unittest.cc",
+      "frame_analyzer/video_color_aligner_unittest.cc",
       "frame_analyzer/video_quality_analysis_unittest.cc",
       "frame_analyzer/video_temporal_aligner_unittest.cc",
       "frame_editing/frame_editing_unittest.cc",
@@ -363,6 +370,7 @@ if (rtc_include_tests) {
       "//test:test_support",
       "//testing/gtest",
       "//third_party/abseil-cpp/absl/memory",
+      "//third_party/libyuv",
     ]
 
     if (rtc_enable_protobuf) {
diff --git a/rtc_tools/frame_analyzer/linear_least_squares.cc b/rtc_tools/frame_analyzer/linear_least_squares.cc
new file mode 100644
index 0000000000..706d212d17
--- /dev/null
+++ b/rtc_tools/frame_analyzer/linear_least_squares.cc
@@ -0,0 +1,200 @@
+/*
+ *  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/linear_least_squares.h"
+
+#include <numeric>
+#include <utility>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+namespace test {
+
+template <class T>
+using Matrix = std::valarray<std::valarray<T>>;
+
+namespace {
+
+template <typename R, typename T>
+R DotProduct(const std::valarray<T>& a, const std::valarray<T>& b) {
+  RTC_CHECK_EQ(a.size(), b.size());
+  return std::inner_product(std::begin(a), std::end(a), std::begin(b), R(0));
+}
+
+// Calculates a^T * b.
+template <typename R, typename T>
+Matrix<R> MatrixMultiply(const Matrix<T>& a, const Matrix<T>& b) {
+  Matrix<R> result(std::valarray<R>(a.size()), b.size());
+  for (size_t i = 0; i < a.size(); ++i) {
+    for (size_t j = 0; j < b.size(); ++j)
+      result[j][i] = DotProduct<R>(a[i], b[j]);
+  }
+
+  return result;
+}
+
+template <typename T>
+Matrix<T> Transpose(const Matrix<T>& matrix) {
+  if (matrix.size() == 0)
+    return Matrix<T>();
+  const size_t rows = matrix.size();
+  const size_t columns = matrix[0].size();
+  Matrix<T> result(std::valarray<T>(rows), columns);
+
+  for (size_t i = 0; i < rows; ++i) {
+    for (size_t j = 0; j < columns; ++j)
+      result[j][i] = matrix[i][j];
+  }
+
+  return result;
+}
+
+// Convert valarray from type T to type R.
+template <typename R, typename T>
+std::valarray<R> ConvertTo(const std::valarray<T>& v) {
+  std::valarray<R> result(v.size());
+  for (size_t i = 0; i < v.size(); ++i)
+    result[i] = static_cast<R>(v[i]);
+  return result;
+}
+
+// Convert valarray Matrix from type T to type R.
+template <typename R, typename T>
+Matrix<R> ConvertTo(const Matrix<T>& mat) {
+  Matrix<R> result(mat.size());
+  for (size_t i = 0; i < mat.size(); ++i)
+    result[i] = ConvertTo<R>(mat[i]);
+  return result;
+}
+
+// Convert from valarray Matrix back to the more conventional std::vector.
+template <typename T>
+std::vector<std::vector<T>> ToVectorMatrix(const Matrix<T>& m) {
+  std::vector<std::vector<T>> result;
+  for (const std::valarray<T>& v : m)
+    result.emplace_back(std::begin(v), std::end(v));
+  return result;
+}
+
+// Create a valarray Matrix from a conventional std::vector.
+template <typename T>
+Matrix<T> FromVectorMatrix(const std::vector<std::vector<T>>& mat) {
+  Matrix<T> result(mat.size());
+  for (size_t i = 0; i < mat.size(); ++i)
+    result[i] = std::valarray<T>(mat[i].data(), mat[i].size());
+  return result;
+}
+
+// Returns |matrix_to_invert|^-1 * |right_hand_matrix|. |matrix_to_invert| must
+// have square size.
+Matrix<double> GaussianElimination(Matrix<double> matrix_to_invert,
+                                   Matrix<double> right_hand_matrix) {
+  // |n| is the width/height of |matrix_to_invert|.
+  const size_t n = matrix_to_invert.size();
+  // Make sure |matrix_to_invert| has square size.
+  for (const std::valarray<double>& column : matrix_to_invert)
+    RTC_CHECK_EQ(n, column.size());
+  // Make sure |right_hand_matrix| has correct size.
+  for (const std::valarray<double>& column : right_hand_matrix)
+    RTC_CHECK_EQ(n, column.size());
+
+  // Transpose the matrices before and after so that we can perform Gaussian
+  // elimination on the columns instead of the rows, since that is easier with
+  // our representation.
+  matrix_to_invert = Transpose(matrix_to_invert);
+  right_hand_matrix = Transpose(right_hand_matrix);
+
+  // Loop over the diagonal of |matrix_to_invert| and perform column reduction.
+  // Column reduction is a sequence of elementary column operations that is
+  // performed on both |matrix_to_invert| and |right_hand_matrix| until
+  // |matrix_to_invert| has been transformed to the identity matrix.
+  for (size_t diagonal_index = 0; diagonal_index < n; ++diagonal_index) {
+    // Make sure the diagonal element has the highest absolute value by
+    // swapping columns if necessary.
+    for (size_t column = diagonal_index + 1; column < n; ++column) {
+      if (std::abs(matrix_to_invert[column][diagonal_index]) >
+          std::abs(matrix_to_invert[diagonal_index][diagonal_index])) {
+        std::swap(matrix_to_invert[column], matrix_to_invert[diagonal_index]);
+        std::swap(right_hand_matrix[column], right_hand_matrix[diagonal_index]);
+      }
+    }
+
+    // Reduce the diagonal element to be 1, by dividing the column with that
+    // value. If the diagonal element is 0, it means the system of equations has
+    // many solutions, and in that case we will return an arbitrary solution.
+    if (matrix_to_invert[diagonal_index][diagonal_index] == 0.0) {
+      RTC_LOG(LS_WARNING) << "Matrix is not invertible, ignoring.";
+      continue;
+    }
+    const double diagonal_element =
+        matrix_to_invert[diagonal_index][diagonal_index];
+    matrix_to_invert[diagonal_index] /= diagonal_element;
+    right_hand_matrix[diagonal_index] /= diagonal_element;
+
+    // Eliminate the other entries in row |diagonal_index| by making them zero.
+    for (size_t column = 0; column < n; ++column) {
+      if (column == diagonal_index)
+        continue;
+      const double row_element = matrix_to_invert[column][diagonal_index];
+      matrix_to_invert[column] -=
+          row_element * matrix_to_invert[diagonal_index];
+      right_hand_matrix[column] -=
+          row_element * right_hand_matrix[diagonal_index];
+    }
+  }
+
+  // Transpose the result before returning it, explained in comment above.
+  return Transpose(right_hand_matrix);
+}
+
+}  // namespace
+
+IncrementalLinearLeastSquares::IncrementalLinearLeastSquares() = default;
+IncrementalLinearLeastSquares::~IncrementalLinearLeastSquares() = default;
+
+void IncrementalLinearLeastSquares::AddObservations(
+    const std::vector<std::vector<uint8_t>>& x,
+    const std::vector<std::vector<uint8_t>>& y) {
+  if (x.empty() || y.empty())
+    return;
+  // Make sure all columns are the same size.
+  const size_t n = x[0].size();
+  for (const std::vector<uint8_t>& column : x)
+    RTC_CHECK_EQ(n, column.size());
+  for (const std::vector<uint8_t>& column : y)
+    RTC_CHECK_EQ(n, column.size());
+
+  // We will multiply the uint8_t values together, so we need to expand to a
+  // type that can safely store those values, i.e. uint16_t.
+  const Matrix<uint16_t> unpacked_x = ConvertTo<uint16_t>(FromVectorMatrix(x));
+  const Matrix<uint16_t> unpacked_y = ConvertTo<uint16_t>(FromVectorMatrix(y));
+
+  const Matrix<uint64_t> xx = MatrixMultiply<uint64_t>(unpacked_x, unpacked_x);
+  const Matrix<uint64_t> xy = MatrixMultiply<uint64_t>(unpacked_x, unpacked_y);
+  if (sum_xx && sum_xy) {
+    *sum_xx += xx;
+    *sum_xy += xy;
+  } else {
+    sum_xx = xx;
+    sum_xy = xy;
+  }
+}
+
+std::vector<std::vector<double>>
+IncrementalLinearLeastSquares::GetBestSolution() const {
+  RTC_CHECK(sum_xx && sum_xy) << "No observations have been added";
+  return ToVectorMatrix(GaussianElimination(ConvertTo<double>(*sum_xx),
+                                            ConvertTo<double>(*sum_xy)));
+}
+
+}  // namespace test
+}  // namespace webrtc
diff --git a/rtc_tools/frame_analyzer/linear_least_squares.h b/rtc_tools/frame_analyzer/linear_least_squares.h
new file mode 100644
index 0000000000..1b07dc1bde
--- /dev/null
+++ b/rtc_tools/frame_analyzer/linear_least_squares.h
@@ -0,0 +1,53 @@
+/*
+ *  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.
+ */
+
+#ifndef RTC_TOOLS_FRAME_ANALYZER_LINEAR_LEAST_SQUARES_H_
+#define RTC_TOOLS_FRAME_ANALYZER_LINEAR_LEAST_SQUARES_H_
+
+#include <valarray>
+#include <vector>
+#include "absl/types/optional.h"
+
+namespace webrtc {
+namespace test {
+
+// This class is used for finding a matrix b that roughly solves the equation:
+// y = x * b. This is generally impossible to do exactly, so the problem is
+// rephrased as finding the matrix b that minimizes the difference:
+// |y - x * b|^2. Calling multiple AddObservations() is equivalent to
+// concatenating the observation vectors and calling AddObservations() once. The
+// reason for doing it incrementally is that we can't store the raw YUV values
+// for a whole video file in memory at once. This class has a constant memory
+// footprint, regardless how may times AddObservations() is called.
+class IncrementalLinearLeastSquares {
+ public:
+  IncrementalLinearLeastSquares();
+  ~IncrementalLinearLeastSquares();
+
+  // Add a number of observations. The subvectors of x and y must have the same
+  // length.
+  void AddObservations(const std::vector<std::vector<uint8_t>>& x,
+                       const std::vector<std::vector<uint8_t>>& y);
+
+  // Calculate and return the best linear solution, given the observations so
+  // far.
+  std::vector<std::vector<double>> GetBestSolution() const;
+
+ private:
+  // Running sum of x^T * x.
+  absl::optional<std::valarray<std::valarray<uint64_t>>> sum_xx;
+  // Running sum of x^T * y.
+  absl::optional<std::valarray<std::valarray<uint64_t>>> sum_xy;
+};
+
+}  // namespace test
+}  // namespace webrtc
+
+#endif  // RTC_TOOLS_FRAME_ANALYZER_LINEAR_LEAST_SQUARES_H_
diff --git a/rtc_tools/frame_analyzer/linear_least_squares_unittest.cc b/rtc_tools/frame_analyzer/linear_least_squares_unittest.cc
new file mode 100644
index 0000000000..b074aacce8
--- /dev/null
+++ b/rtc_tools/frame_analyzer/linear_least_squares_unittest.cc
@@ -0,0 +1,91 @@
+/*
+ *  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/linear_least_squares.h"
+
+#include "test/gtest.h"
+
+namespace webrtc {
+namespace test {
+
+TEST(LinearLeastSquares, ScalarIdentityOneObservation) {
+  IncrementalLinearLeastSquares lls;
+  lls.AddObservations({{1}}, {{1}});
+  EXPECT_EQ(std::vector<std::vector<double>>({{1.0}}), lls.GetBestSolution());
+}
+
+TEST(LinearLeastSquares, ScalarIdentityTwoObservationsOneCall) {
+  IncrementalLinearLeastSquares lls;
+  lls.AddObservations({{1, 2}}, {{1, 2}});
+  EXPECT_EQ(std::vector<std::vector<double>>({{1.0}}), lls.GetBestSolution());
+}
+
+TEST(LinearLeastSquares, ScalarIdentityTwoObservationsTwoCalls) {
+  IncrementalLinearLeastSquares lls;
+  lls.AddObservations({{1}}, {{1}});
+  lls.AddObservations({{2}}, {{2}});
+  EXPECT_EQ(std::vector<std::vector<double>>({{1.0}}), lls.GetBestSolution());
+}
+
+TEST(LinearLeastSquares, MatrixIdentityOneObservation) {
+  IncrementalLinearLeastSquares lls;
+  lls.AddObservations({{1, 2}, {3, 4}}, {{1, 2}, {3, 4}});
+  EXPECT_EQ(std::vector<std::vector<double>>({{1.0, 0.0}, {0.0, 1.0}}),
+            lls.GetBestSolution());
+}
+
+TEST(LinearLeastSquares, MatrixManyObservations) {
+  IncrementalLinearLeastSquares lls;
+  // Test that we can find the solution of the overspecified equation system:
+  // [1, 2] [1, 3] = [5,  11]
+  // [3, 4] [2, 4]   [11, 25]
+  // [5, 6]          [17, 39]
+  lls.AddObservations({{1}, {2}}, {{5}, {11}});
+  lls.AddObservations({{3}, {4}}, {{11}, {25}});
+  lls.AddObservations({{5}, {6}}, {{17}, {39}});
+
+  const std::vector<std::vector<double>> result = lls.GetBestSolution();
+  // We allow some numerical flexibility here.
+  EXPECT_DOUBLE_EQ(1.0, result[0][0]);
+  EXPECT_DOUBLE_EQ(2.0, result[0][1]);
+  EXPECT_DOUBLE_EQ(3.0, result[1][0]);
+  EXPECT_DOUBLE_EQ(4.0, result[1][1]);
+}
+
+TEST(LinearLeastSquares, MatrixVectorOneObservation) {
+  IncrementalLinearLeastSquares lls;
+  // Test that we can find the solution of the overspecified equation system:
+  // [1, 2] [1] = [5]
+  // [3, 4] [2]   [11]
+  // [5, 6]       [17]
+  lls.AddObservations({{1, 3, 5}, {2, 4, 6}}, {{5, 11, 17}});
+
+  const std::vector<std::vector<double>> result = lls.GetBestSolution();
+  // We allow some numerical flexibility here.
+  EXPECT_DOUBLE_EQ(1.0, result[0][0]);
+  EXPECT_DOUBLE_EQ(2.0, result[0][1]);
+}
+
+TEST(LinearLeastSquares, LinearLeastSquaresNonPerfectSolution) {
+  IncrementalLinearLeastSquares lls;
+  // Test that we can find the non-perfect solution of the overspecified
+  // equation system:
+  // [1] [20] = [21]
+  // [2]        [39]
+  // [3]        [60]
+  // [2]        [41]
+  // [1]        [19]
+  lls.AddObservations({{1, 2, 3, 2, 1}}, {{21, 39, 60, 41, 19}});
+
+  EXPECT_DOUBLE_EQ(20.0, lls.GetBestSolution()[0][0]);
+}
+
+}  // namespace test
+}  // namespace webrtc
diff --git a/rtc_tools/frame_analyzer/video_color_aligner.cc b/rtc_tools/frame_analyzer/video_color_aligner.cc
new file mode 100644
index 0000000000..7afb1e4695
--- /dev/null
+++ b/rtc_tools/frame_analyzer/video_color_aligner.cc
@@ -0,0 +1,239 @@
+/*
+ *  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 <algorithm>
+#include <cmath>
+#include <deque>
+#include <limits>
+#include <vector>
+
+#include "api/array_view.h"
+#include "api/video/i420_buffer.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/refcountedobject.h"
+#include "rtc_tools/frame_analyzer/linear_least_squares.h"
+#include "rtc_tools/frame_analyzer/video_quality_analysis.h"
+#include "third_party/libyuv/include/libyuv/compare.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 rtc::RefCountedObject<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 new 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
diff --git a/rtc_tools/frame_analyzer/video_color_aligner.h b/rtc_tools/frame_analyzer/video_color_aligner.h
new file mode 100644
index 0000000000..997cbf6582
--- /dev/null
+++ b/rtc_tools/frame_analyzer/video_color_aligner.h
@@ -0,0 +1,49 @@
+/*
+ *  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.
+ */
+
+#ifndef RTC_TOOLS_FRAME_ANALYZER_VIDEO_COLOR_ALIGNER_H_
+#define RTC_TOOLS_FRAME_ANALYZER_VIDEO_COLOR_ALIGNER_H_
+
+#include <array>
+
+#include "rtc_tools/video_file_reader.h"
+
+namespace webrtc {
+namespace test {
+
+// Represents a linear color transformation from [y, u, v] to [y', u', v']
+// through the equation: [y', u', v'] = [y, u, v, 1] * matrix.
+using ColorTransformationMatrix = std::array<std::array<float, 4>, 3>;
+
+// Calculate the optimal color transformation that should be applied to the test
+// video to match as closely as possible to the reference video.
+ColorTransformationMatrix CalculateColorTransformationMatrix(
+    const rtc::scoped_refptr<Video>& reference_video,
+    const rtc::scoped_refptr<Video>& test_video);
+
+// Calculate color transformation for a single I420 frame.
+ColorTransformationMatrix CalculateColorTransformationMatrix(
+    const rtc::scoped_refptr<I420BufferInterface>& reference_frame,
+    const rtc::scoped_refptr<I420BufferInterface>& test_frame);
+
+// Apply a color transformation to a video.
+rtc::scoped_refptr<Video> AdjustColors(
+    const ColorTransformationMatrix& color_matrix,
+    const rtc::scoped_refptr<Video>& video);
+
+// Apply a color transformation to a single I420 frame.
+rtc::scoped_refptr<I420BufferInterface> AdjustColors(
+    const ColorTransformationMatrix& color_matrix,
+    const rtc::scoped_refptr<I420BufferInterface>& frame);
+
+}  // namespace test
+}  // namespace webrtc
+
+#endif  // RTC_TOOLS_FRAME_ANALYZER_VIDEO_COLOR_ALIGNER_H_
diff --git a/rtc_tools/frame_analyzer/video_color_aligner_unittest.cc b/rtc_tools/frame_analyzer/video_color_aligner_unittest.cc
new file mode 100644
index 0000000000..520d6f459e
--- /dev/null
+++ b/rtc_tools/frame_analyzer/video_color_aligner_unittest.cc
@@ -0,0 +1,174 @@
+/*
+ *  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 "rtc_tools/frame_analyzer/video_quality_analysis.h"
+#include "rtc_tools/video_file_reader.h"
+#include "test/gtest.h"
+#include "test/testsupport/fileutils.h"
+#include "third_party/libyuv/include/libyuv/scale.h"
+
+namespace webrtc {
+namespace test {
+
+namespace {
+
+const ColorTransformationMatrix kIdentityColorMatrix = {
+    {{1, 0, 0, 0}, {0, 1, 0, 0}, {0, 0, 1, 0}}};
+
+void ExpectNear(const ColorTransformationMatrix& expected,
+                const ColorTransformationMatrix& actual) {
+  // The scaling factor on y/u/v should be pretty precise.
+  for (int i = 0; i < 3; ++i) {
+    for (int j = 0; j < 3; ++j)
+      EXPECT_NEAR(expected[i][j], actual[i][j], /* abs_error= */ 1.0e-3)
+          << "at element i: " << i << ", j: " << j;
+  }
+  // The offset can be less precise since the range is [0, 255].
+  for (int i = 0; i < 3; ++i)
+    EXPECT_NEAR(expected[i][3], actual[i][3], /* abs_error= */ 0.1)
+        << "at element i: " << i;
+}
+
+}  // namespace
+
+class VideoColorAlignerTest : public ::testing::Test {
+ protected:
+  void SetUp() {
+    reference_video_ =
+        OpenYuvFile(ResourcePath("foreman_128x96", "yuv"), 128, 96);
+    ASSERT_TRUE(reference_video_);
+  }
+
+  rtc::scoped_refptr<Video> reference_video_;
+};
+
+TEST_F(VideoColorAlignerTest, AdjustColorsFrameIdentity) {
+  const rtc::scoped_refptr<I420BufferInterface> test_frame =
+      reference_video_->GetFrame(0);
+
+  // Assume perfect match, i.e. ssim == 1.
+  EXPECT_EQ(1.0,
+            Ssim(test_frame, AdjustColors(kIdentityColorMatrix, test_frame)));
+}
+
+TEST_F(VideoColorAlignerTest, AdjustColorsFrame1x1) {
+  const ColorTransformationMatrix color_matrix = {
+      {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}}};
+
+  const uint8_t data_y[] = {2};
+  const uint8_t data_u[] = {6};
+  const uint8_t data_v[] = {7};
+  const rtc::scoped_refptr<I420BufferInterface> i420_buffer = I420Buffer::Copy(
+      /* width= */ 1, /* height= */ 1, data_y, /* stride_y= */ 1, data_u,
+      /* stride_u= */ 1, data_v, /* stride_v= */ 1);
+
+  const rtc::scoped_refptr<I420BufferInterface> adjusted_buffer =
+      AdjustColors(color_matrix, i420_buffer);
+
+  EXPECT_EQ(2 * 1 + 6 * 2 + 7 * 3 + 4, adjusted_buffer->DataY()[0]);
+  EXPECT_EQ(2 * 5 + 6 * 6 + 7 * 7 + 8, adjusted_buffer->DataU()[0]);
+  EXPECT_EQ(2 * 9 + 6 * 10 + 7 * 11 + 12, adjusted_buffer->DataV()[0]);
+}
+
+TEST_F(VideoColorAlignerTest, AdjustColorsFrame1x1Negative) {
+  const ColorTransformationMatrix color_matrix = {
+      {{-1, 0, 0, 255}, {0, -1, 0, 255}, {0, 0, -1, 255}}};
+
+  const uint8_t data_y[] = {2};
+  const uint8_t data_u[] = {6};
+  const uint8_t data_v[] = {7};
+  const rtc::scoped_refptr<I420BufferInterface> i420_buffer = I420Buffer::Copy(
+      /* width= */ 1, /* height= */ 1, data_y, /* stride_y= */ 1, data_u,
+      /* stride_u= */ 1, data_v, /* stride_v= */ 1);
+
+  const rtc::scoped_refptr<I420BufferInterface> adjusted_buffer =
+      AdjustColors(color_matrix, i420_buffer);
+
+  EXPECT_EQ(255 - 2, adjusted_buffer->DataY()[0]);
+  EXPECT_EQ(255 - 6, adjusted_buffer->DataU()[0]);
+  EXPECT_EQ(255 - 7, adjusted_buffer->DataV()[0]);
+}
+
+TEST_F(VideoColorAlignerTest, AdjustColorsFrame2x2) {
+  const ColorTransformationMatrix color_matrix = {
+      {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}}};
+
+  const uint8_t data_y[] = {0, 1, 3, 4};
+  const uint8_t data_u[] = {6};
+  const uint8_t data_v[] = {7};
+  const rtc::scoped_refptr<I420BufferInterface> i420_buffer = I420Buffer::Copy(
+      /* width= */ 2, /* height= */ 2, data_y, /* stride_y= */ 2, data_u,
+      /* stride_u= */ 1, data_v, /* stride_v= */ 1);
+
+  const rtc::scoped_refptr<I420BufferInterface> adjusted_buffer =
+      AdjustColors(color_matrix, i420_buffer);
+
+  EXPECT_EQ(0 * 1 + 6 * 2 + 7 * 3 + 4, adjusted_buffer->DataY()[0]);
+  EXPECT_EQ(1 * 1 + 6 * 2 + 7 * 3 + 4, adjusted_buffer->DataY()[1]);
+  EXPECT_EQ(3 * 1 + 6 * 2 + 7 * 3 + 4, adjusted_buffer->DataY()[2]);
+  EXPECT_EQ(4 * 1 + 6 * 2 + 7 * 3 + 4, adjusted_buffer->DataY()[3]);
+
+  EXPECT_EQ(2 * 5 + 6 * 6 + 7 * 7 + 8, adjusted_buffer->DataU()[0]);
+  EXPECT_EQ(2 * 9 + 6 * 10 + 7 * 11 + 12, adjusted_buffer->DataV()[0]);
+}
+
+TEST_F(VideoColorAlignerTest, CalculateColorTransformationMatrixIdentity) {
+  EXPECT_EQ(kIdentityColorMatrix, CalculateColorTransformationMatrix(
+                                      reference_video_, reference_video_));
+}
+
+TEST_F(VideoColorAlignerTest, CalculateColorTransformationMatrixOffset) {
+  const uint8_t small_data_y[] = {0, 1, 2,  3,  4,  5,  6,  7,
+                                  8, 9, 10, 11, 12, 13, 14, 15};
+  const uint8_t small_data_u[] = {15, 13, 17, 29};
+  const uint8_t small_data_v[] = {3, 200, 170, 29};
+  const rtc::scoped_refptr<I420BufferInterface> small_i420_buffer =
+      I420Buffer::Copy(
+          /* width= */ 4, /* height= */ 4, small_data_y, /* stride_y= */ 4,
+          small_data_u, /* stride_u= */ 2, small_data_v, /* stride_v= */ 2);
+
+  uint8_t big_data_y[16];
+  uint8_t big_data_u[4];
+  uint8_t big_data_v[4];
+  // Create another I420 frame where all values are 10 bigger.
+  for (int i = 0; i < 16; ++i)
+    big_data_y[i] = small_data_y[i] + 10;
+  for (int i = 0; i < 4; ++i)
+    big_data_u[i] = small_data_u[i] + 10;
+  for (int i = 0; i < 4; ++i)
+    big_data_v[i] = small_data_v[i] + 10;
+
+  const rtc::scoped_refptr<I420BufferInterface> big_i420_buffer =
+      I420Buffer::Copy(
+          /* width= */ 4, /* height= */ 4, big_data_y, /* stride_y= */ 4,
+          big_data_u, /* stride_u= */ 2, big_data_v, /* stride_v= */ 2);
+
+  const ColorTransformationMatrix color_matrix =
+      CalculateColorTransformationMatrix(big_i420_buffer, small_i420_buffer);
+
+  ExpectNear({{{1, 0, 0, 10}, {0, 1, 0, 10}, {0, 0, 1, 10}}}, color_matrix);
+}
+
+TEST_F(VideoColorAlignerTest, CalculateColorTransformationMatrix) {
+  // Arbitrary color transformation matrix.
+  const ColorTransformationMatrix org_color_matrix = {
+      {{0.8, 0.05, 0.04, -4}, {-0.2, 0.7, 0.1, 10}, {0.1, 0.2, 0.4, 20}}};
+
+  const ColorTransformationMatrix result_color_matrix =
+      CalculateColorTransformationMatrix(
+          AdjustColors(org_color_matrix, reference_video_), reference_video_);
+
+  ExpectNear(org_color_matrix, result_color_matrix);
+}
+
+}  // namespace test
+}  // namespace webrtc