diff --git a/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/RgbaMatrixPixelTest.java b/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/RgbaMatrixPixelTest.java
new file mode 100644
index 0000000000..3d4419fddd
--- /dev/null
+++ b/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/RgbaMatrixPixelTest.java
@@ -0,0 +1,234 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.transformer;
+
+import static androidx.test.core.app.ApplicationProvider.getApplicationContext;
+import static com.google.android.exoplayer2.transformer.BitmapTestUtil.MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE;
+import static com.google.android.exoplayer2.util.Assertions.checkNotNull;
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Color;
+import android.opengl.EGLContext;
+import android.opengl.EGLDisplay;
+import android.opengl.EGLSurface;
+import android.opengl.Matrix;
+import android.util.Pair;
+import androidx.media3.common.FrameProcessingException;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import com.google.android.exoplayer2.util.GlUtil;
+import java.io.IOException;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * Pixel tests for {@link RgbaMatrix}.
+ *
+ *
Expected images are taken from an emulator, so tests on different emulators or physical
+ * devices may fail. To test on other devices, please increase the {@link
+ * BitmapTestUtil#MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE} and/or inspect the saved output bitmaps
+ * as recommended in {@link GlEffectsFrameProcessorPixelTest}.
+ */
+@RunWith(AndroidJUnit4.class)
+public final class RgbaMatrixPixelTest {
+ public static final String ORIGINAL_PNG_ASSET_PATH =
+ "media/bitmap/sample_mp4_first_frame/original.png";
+ public static final String ONLY_RED_CHANNEL_PNG_ASSET_PATH =
+ "media/bitmap/sample_mp4_first_frame/only_red_channel.png";
+ public static final String INCREASE_BRIGHTNESS_PNG_ASSET_PATH =
+ "media/bitmap/sample_mp4_first_frame/increase_brightness.png";
+ public static final String GRAYSCALE_PNG_ASSET_PATH =
+ "media/bitmap/sample_mp4_first_frame/grayscale.png";
+ public static final int COLOR_MATRIX_RED_INDEX = 0;
+ public static final int COLOR_MATRIX_GREEN_INDEX = 5;
+ public static final int COLOR_MATRIX_BLUE_INDEX = 10;
+ public static final int COLOR_MATRIX_ALPHA_INDEX = 15;
+
+ private final Context context = getApplicationContext();
+
+ private @MonotonicNonNull EGLDisplay eglDisplay;
+ private @MonotonicNonNull EGLContext eglContext;
+ private @MonotonicNonNull SingleFrameGlTextureProcessor rgbaMatrixProcessor;
+ private @MonotonicNonNull EGLSurface placeholderEglSurface;
+ private int inputTexId;
+ private int outputTexId;
+ private int inputWidth;
+ private int inputHeight;
+
+ @Before
+ public void createGlObjects() throws IOException, GlUtil.GlException {
+ eglDisplay = GlUtil.createEglDisplay();
+ eglContext = GlUtil.createEglContext(eglDisplay);
+ Bitmap inputBitmap = BitmapTestUtil.readBitmap(ORIGINAL_PNG_ASSET_PATH);
+ inputWidth = inputBitmap.getWidth();
+ inputHeight = inputBitmap.getHeight();
+ placeholderEglSurface = GlUtil.createPlaceholderEglSurface(eglDisplay);
+ GlUtil.focusEglSurface(eglDisplay, eglContext, placeholderEglSurface, inputWidth, inputHeight);
+ inputTexId = BitmapTestUtil.createGlTextureFromBitmap(inputBitmap);
+
+ outputTexId =
+ GlUtil.createTexture(inputWidth, inputHeight, /* useHighPrecisionColorComponents= */ false);
+ int frameBuffer = GlUtil.createFboForTexture(outputTexId);
+ GlUtil.focusFramebuffer(
+ checkNotNull(eglDisplay),
+ checkNotNull(eglContext),
+ checkNotNull(placeholderEglSurface),
+ frameBuffer,
+ inputWidth,
+ inputHeight);
+ }
+
+ @After
+ public void release() throws GlUtil.GlException, FrameProcessingException {
+ if (rgbaMatrixProcessor != null) {
+ rgbaMatrixProcessor.release();
+ }
+ GlUtil.destroyEglContext(eglDisplay, eglContext);
+ }
+
+ private static RgbaMatrixProcessor createRgbaMatrixProcessor(Context context, float[] rgbaMatrix)
+ throws FrameProcessingException {
+ return ((RgbaMatrix) presentationTimeUs -> rgbaMatrix)
+ .toGlTextureProcessor(context, /* useHdr= */ false);
+ }
+
+ @Test
+ public void drawFrame_identityMatrix_leavesFrameUnchanged() throws Exception {
+ String testId = "drawFrame_identityMatrix";
+ float[] identityMatrix = new float[16];
+ Matrix.setIdentityM(identityMatrix, /* smOffset= */ 0);
+ rgbaMatrixProcessor = createRgbaMatrixProcessor(context, identityMatrix);
+ Pair outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
+ Bitmap expectedBitmap = BitmapTestUtil.readBitmap(ORIGINAL_PNG_ASSET_PATH);
+
+ rgbaMatrixProcessor.drawFrame(inputTexId, /* presentationTimeUs= */ 0);
+ Bitmap actualBitmap =
+ BitmapTestUtil.createArgb8888BitmapFromCurrentGlFramebuffer(
+ outputSize.first, outputSize.second);
+
+ BitmapTestUtil.maybeSaveTestBitmapToCacheDirectory(
+ testId, /* bitmapLabel= */ "actual", actualBitmap);
+ float averagePixelAbsoluteDifference =
+ BitmapTestUtil.getAveragePixelAbsoluteDifferenceArgb8888(
+ expectedBitmap, actualBitmap, testId);
+ assertThat(averagePixelAbsoluteDifference).isAtMost(MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE);
+ }
+
+ @Test
+ public void drawFrame_removeColors_producesBlackFrame() throws Exception {
+ String testId = "drawFrame_removeColors";
+ float[] removeColorFilter = new float[16];
+ Matrix.setIdentityM(removeColorFilter, /* smOffset= */ 0);
+ removeColorFilter[COLOR_MATRIX_RED_INDEX] = 0;
+ removeColorFilter[COLOR_MATRIX_GREEN_INDEX] = 0;
+ removeColorFilter[COLOR_MATRIX_BLUE_INDEX] = 0;
+ rgbaMatrixProcessor = createRgbaMatrixProcessor(context, removeColorFilter);
+ Pair outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
+ Bitmap expectedBitmap =
+ BitmapTestUtil.createArgb8888BitmapWithSolidColor(
+ outputSize.first, outputSize.second, Color.BLACK);
+
+ rgbaMatrixProcessor.drawFrame(inputTexId, /* presentationTimeUs= */ 0);
+ Bitmap actualBitmap =
+ BitmapTestUtil.createArgb8888BitmapFromCurrentGlFramebuffer(
+ outputSize.first, outputSize.second);
+
+ BitmapTestUtil.maybeSaveTestBitmapToCacheDirectory(
+ testId, /* bitmapLabel= */ "actual", actualBitmap);
+ float averagePixelAbsoluteDifference =
+ BitmapTestUtil.getAveragePixelAbsoluteDifferenceArgb8888(
+ expectedBitmap, actualBitmap, testId);
+ assertThat(averagePixelAbsoluteDifference).isAtMost(MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE);
+ }
+
+ @Test
+ public void drawFrame_redOnlyFilter_setsBlueAndGreenValuesToZero() throws Exception {
+ String testId = "drawFrame_redOnlyFilter";
+ float[] redOnlyFilter = new float[16];
+ Matrix.setIdentityM(redOnlyFilter, /* smOffset= */ 0);
+ redOnlyFilter[COLOR_MATRIX_GREEN_INDEX] = 0;
+ redOnlyFilter[COLOR_MATRIX_BLUE_INDEX] = 0;
+ rgbaMatrixProcessor = createRgbaMatrixProcessor(context, redOnlyFilter);
+ Pair outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
+ Bitmap expectedBitmap = BitmapTestUtil.readBitmap(ONLY_RED_CHANNEL_PNG_ASSET_PATH);
+
+ rgbaMatrixProcessor.drawFrame(inputTexId, /* presentationTimeUs= */ 0);
+ Bitmap actualBitmap =
+ BitmapTestUtil.createArgb8888BitmapFromCurrentGlFramebuffer(
+ outputSize.first, outputSize.second);
+
+ BitmapTestUtil.maybeSaveTestBitmapToCacheDirectory(
+ testId, /* bitmapLabel= */ "actual", actualBitmap);
+ float averagePixelAbsoluteDifference =
+ BitmapTestUtil.getAveragePixelAbsoluteDifferenceArgb8888(
+ expectedBitmap, actualBitmap, testId);
+ assertThat(averagePixelAbsoluteDifference).isAtMost(MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE);
+ }
+
+ @Test
+ public void drawFrame_increaseBrightness_increasesAllValues() throws Exception {
+ String testId = "drawFrame_increaseBrightness";
+ float[] increaseBrightnessMatrix = new float[16];
+ Matrix.setIdentityM(increaseBrightnessMatrix, /* smOffset= */ 0);
+ Matrix.scaleM(increaseBrightnessMatrix, /* mOffset= */ 0, /* x= */ 5, /* y= */ 5, /* z= */ 5);
+ rgbaMatrixProcessor = createRgbaMatrixProcessor(context, increaseBrightnessMatrix);
+ Pair outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
+ Bitmap expectedBitmap = BitmapTestUtil.readBitmap(INCREASE_BRIGHTNESS_PNG_ASSET_PATH);
+
+ rgbaMatrixProcessor.drawFrame(inputTexId, /* presentationTimeUs= */ 0);
+ Bitmap actualBitmap =
+ BitmapTestUtil.createArgb8888BitmapFromCurrentGlFramebuffer(
+ outputSize.first, outputSize.second);
+
+ BitmapTestUtil.maybeSaveTestBitmapToCacheDirectory(
+ testId, /* bitmapLabel= */ "actual", actualBitmap);
+ float averagePixelAbsoluteDifference =
+ BitmapTestUtil.getAveragePixelAbsoluteDifferenceArgb8888(
+ expectedBitmap, actualBitmap, testId);
+ assertThat(averagePixelAbsoluteDifference).isAtMost(MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE);
+ }
+
+ @Test
+ public void drawFrame_grayscale_producesGrayscaleImage() throws Exception {
+ String testId = "drawFrame_grayscale";
+ // Grayscale transformation matrix with the BT.709 standard from
+ // https://en.wikipedia.org/wiki/Grayscale#Converting_colour_to_grayscale
+ float[] grayscaleFilter = {
+ 0.2126f, 0.2126f, 0.2126f, 0, 0.7152f, 0.7152f, 0.7152f, 0, 0.0722f, 0.0722f, 0.0722f, 0, 0,
+ 0, 0, 1
+ };
+ rgbaMatrixProcessor = createRgbaMatrixProcessor(context, grayscaleFilter);
+ Pair outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
+ Bitmap expectedBitmap = BitmapTestUtil.readBitmap(GRAYSCALE_PNG_ASSET_PATH);
+
+ rgbaMatrixProcessor.drawFrame(inputTexId, /* presentationTimeUs= */ 0);
+ Bitmap actualBitmap =
+ BitmapTestUtil.createArgb8888BitmapFromCurrentGlFramebuffer(
+ outputSize.first, outputSize.second);
+
+ BitmapTestUtil.maybeSaveTestBitmapToCacheDirectory(
+ testId, /* bitmapLabel= */ "actual", actualBitmap);
+ float averagePixelAbsoluteDifference =
+ BitmapTestUtil.getAveragePixelAbsoluteDifferenceArgb8888(
+ expectedBitmap, actualBitmap, testId);
+ assertThat(averagePixelAbsoluteDifference).isAtMost(MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE);
+ }
+}
diff --git a/library/transformer/src/main/assets/shaders/fragment_shader_transformation_es2.glsl b/library/transformer/src/main/assets/shaders/fragment_shader_transformation_es2.glsl
new file mode 100644
index 0000000000..4b70580e26
--- /dev/null
+++ b/library/transformer/src/main/assets/shaders/fragment_shader_transformation_es2.glsl
@@ -0,0 +1,28 @@
+#version 100
+// Copyright 2022 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// ES 2 fragment shader that samples from a (non-external) texture with
+// uTexSampler, copying from this texture to the current output while
+// applying a 4x4 RGBA color matrix to change the pixel colors.
+
+precision mediump float;
+uniform sampler2D uTexSampler;
+uniform mat4 uColorMatrix;
+varying vec2 vTexSamplingCoord;
+
+void main() {
+ vec4 inputColor = texture2D(uTexSampler, vTexSamplingCoord);
+ gl_FragColor = uColorMatrix * inputColor;
+}
diff --git a/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/RgbaMatrix.java b/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/RgbaMatrix.java
new file mode 100644
index 0000000000..1c2ceb0efe
--- /dev/null
+++ b/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/RgbaMatrix.java
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.transformer;
+
+import android.content.Context;
+import androidx.media3.common.FrameProcessingException;
+
+/**
+ * Specifies a 4x4 RGBA color transformation matrix to apply to each frame in the fragment shader.
+ */
+public interface RgbaMatrix extends GlEffect {
+
+ /**
+ * Returns the 4x4 RGBA transformation {@linkplain android.opengl.Matrix matrix} to apply to the
+ * color values of each pixel in the frame with the given timestamp.
+ */
+ float[] getMatrix(long presentationTimeUs);
+
+ @Override
+ default RgbaMatrixProcessor toGlTextureProcessor(Context context, boolean useHdr)
+ throws FrameProcessingException {
+ return new RgbaMatrixProcessor(context, /* rgbaMatrix= */ this, useHdr);
+ }
+}
diff --git a/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/RgbaMatrixProcessor.java b/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/RgbaMatrixProcessor.java
new file mode 100644
index 0000000000..9c9b9e0195
--- /dev/null
+++ b/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/RgbaMatrixProcessor.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.exoplayer2.transformer;
+
+import android.content.Context;
+import android.opengl.GLES20;
+import android.opengl.Matrix;
+import android.util.Pair;
+import androidx.media3.common.FrameProcessingException;
+import com.google.android.exoplayer2.util.GlProgram;
+import com.google.android.exoplayer2.util.GlUtil;
+import java.io.IOException;
+
+/** Applies an {@link RgbaMatrix} to each frame. */
+/* package */ final class RgbaMatrixProcessor extends SingleFrameGlTextureProcessor {
+ private static final String VERTEX_SHADER_PATH = "shaders/vertex_shader_transformation_es2.glsl";
+ private static final String FRAGMENT_SHADER_PATH =
+ "shaders/fragment_shader_transformation_es2.glsl";
+
+ private final GlProgram glProgram;
+ private final RgbaMatrix rgbaMatrix;
+
+ // TODO(b/239431666): Support chaining multiple RgbaMatrix instances in RgbaMatrixProcessor.
+ // TODO(b/239757183): Merge RgbaMatrixProcessor with MatrixTransformationProcessor.
+ public RgbaMatrixProcessor(Context context, RgbaMatrix rgbaMatrix, boolean useHdr)
+ throws FrameProcessingException {
+ super(useHdr);
+ this.rgbaMatrix = rgbaMatrix;
+
+ try {
+ glProgram = new GlProgram(context, VERTEX_SHADER_PATH, FRAGMENT_SHADER_PATH);
+ } catch (IOException | GlUtil.GlException e) {
+ throw new FrameProcessingException(e);
+ }
+
+ // Draw the frame on the entire normalized device coordinate space, from -1 to 1, for x and y.
+ glProgram.setBufferAttribute(
+ "aFramePosition",
+ GlUtil.getNormalizedCoordinateBounds(),
+ GlUtil.HOMOGENEOUS_COORDINATE_VECTOR_SIZE);
+
+ float[] identityMatrix = new float[16];
+ Matrix.setIdentityM(identityMatrix, /* smOffset= */ 0);
+ glProgram.setFloatsUniform("uTransformationMatrix", identityMatrix);
+ glProgram.setFloatsUniform("uTexTransformationMatrix", identityMatrix);
+ }
+
+ @Override
+ public Pair configure(int inputWidth, int inputHeight) {
+ return Pair.create(inputWidth, inputHeight);
+ }
+
+ @Override
+ public void drawFrame(int inputTexId, long presentationTimeUs) throws FrameProcessingException {
+ float[] rgbaMatrixArray = rgbaMatrix.getMatrix(presentationTimeUs);
+ try {
+ glProgram.use();
+ glProgram.setSamplerTexIdUniform("uTexSampler", inputTexId, /* texUnitIndex= */ 0);
+ glProgram.setFloatsUniform("uColorMatrix", rgbaMatrixArray);
+ glProgram.bindAttributesAndUniforms();
+
+ // The four-vertex triangle strip forms a quad.
+ GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, /* first= */ 0, /* count= */ 4);
+ } catch (GlUtil.GlException e) {
+ throw new FrameProcessingException(e, presentationTimeUs);
+ }
+ }
+}
diff --git a/testdata/src/test/assets/media/bitmap/sample_mp4_first_frame/grayscale.png b/testdata/src/test/assets/media/bitmap/sample_mp4_first_frame/grayscale.png
new file mode 100644
index 0000000000..11b83d2320
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diff --git a/testdata/src/test/assets/media/bitmap/sample_mp4_first_frame/increase_brightness.png b/testdata/src/test/assets/media/bitmap/sample_mp4_first_frame/increase_brightness.png
new file mode 100644
index 0000000000..2d65aaa29f
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diff --git a/testdata/src/test/assets/media/bitmap/sample_mp4_first_frame/only_red_channel.png b/testdata/src/test/assets/media/bitmap/sample_mp4_first_frame/only_red_channel.png
new file mode 100644
index 0000000000..56d38b4e21
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