Add RgbAdjustment class to build RgbaMatrices

* Add RgbaMatrix interface implementation.
* Add Builder class for easy adjustments.
* Adjust existing RgbaMatrixPixelTests to use new RgbAdjustment class.

PiperOrigin-RevId: 465545429

libraries/effect/src/androidTest/java/androidx/media3/effect/RgbAdjustmentPixelTest.java

@@ -27,7 +27,6 @@ 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.media3.common.util.GlUtil;
@@ -48,19 +47,17 @@ import org.junit.runner.RunWith;
  * as recommended in {@link GlEffectsFrameProcessorPixelTest}.
  */
 @RunWith(AndroidJUnit4.class)
-public final class RgbaMatrixPixelTest {
+public final class RgbAdjustmentPixelTest {
   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_RED_CHANNEL_PNG_ASSET_PATH =
+      "media/bitmap/sample_mp4_first_frame/increase_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();
 
@@ -113,9 +110,8 @@ public final class RgbaMatrixPixelTest {
   @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);
+    RgbaMatrix identityMatrix = new RgbAdjustment.Builder().build();
+    rgbaMatrixProcessor = new RgbaMatrixProcessor(context, identityMatrix, /* useHdr= */ false);
     Pair<Integer, Integer> outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
     Bitmap expectedBitmap = BitmapTestUtil.readBitmap(ORIGINAL_PNG_ASSET_PATH);
 
@@ -135,12 +131,9 @@ public final class RgbaMatrixPixelTest {
   @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);
+    RgbaMatrix removeColorMatrix =
+        new RgbAdjustment.Builder().setRedScale(0).setGreenScale(0).setBlueScale(0).build();
+    rgbaMatrixProcessor = new RgbaMatrixProcessor(context, removeColorMatrix, /* useHdr= */ false);
     Pair<Integer, Integer> outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
     Bitmap expectedBitmap =
         BitmapTestUtil.createArgb8888BitmapWithSolidColor(
@@ -162,11 +155,8 @@ public final class RgbaMatrixPixelTest {
   @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);
+    RgbaMatrix redOnlyMatrix = new RgbAdjustment.Builder().setBlueScale(0).setGreenScale(0).build();
+    rgbaMatrixProcessor = new RgbaMatrixProcessor(context, redOnlyMatrix, /* useHdr= */ false);
     Pair<Integer, Integer> outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
     Bitmap expectedBitmap = BitmapTestUtil.readBitmap(ONLY_RED_CHANNEL_PNG_ASSET_PATH);
 
@@ -183,13 +173,34 @@ public final class RgbaMatrixPixelTest {
     assertThat(averagePixelAbsoluteDifference).isAtMost(MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE);
   }
 
+  @Test
+  public void drawFrame_increaseRedChannel_producesBrighterAndRedderFrame() throws Exception {
+    String testId = "drawFrame_increaseRedChannel";
+    RgbaMatrix increaseRedMatrix = new RgbAdjustment.Builder().setRedScale(5).build();
+    rgbaMatrixProcessor = new RgbaMatrixProcessor(context, increaseRedMatrix, /* useHdr= */ false);
+    Pair<Integer, Integer> outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
+    Bitmap expectedBitmap = BitmapTestUtil.readBitmap(INCREASE_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);
+    RgbaMatrix increaseBrightnessMatrix =
+        new RgbAdjustment.Builder().setRedScale(5).setGreenScale(5).setBlueScale(5).build();
+    rgbaMatrixProcessor =
+        new RgbaMatrixProcessor(context, increaseBrightnessMatrix, /* useHdr = */ false);
     Pair<Integer, Integer> outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
     Bitmap expectedBitmap = BitmapTestUtil.readBitmap(INCREASE_BRIGHTNESS_PNG_ASSET_PATH);
 
@@ -207,15 +218,16 @@ public final class RgbaMatrixPixelTest {
   }
 
   @Test
+  // TODO(b/239430283): Move test to RgbFilterPixelTest once it exists.
   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 = {
+    float[] grayscaleMatrix = {
       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);
+    rgbaMatrixProcessor = createRgbaMatrixProcessor(/* context= */ context, grayscaleMatrix);
     Pair<Integer, Integer> outputSize = rgbaMatrixProcessor.configure(inputWidth, inputHeight);
     Bitmap expectedBitmap = BitmapTestUtil.readBitmap(GRAYSCALE_PNG_ASSET_PATH);
 

libraries/effect/src/main/java/androidx/media3/effect/RgbAdjustment.java

@@ -0,0 +1,106 @@
+/*
+ * 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 androidx.media3.effect;
+
+import static androidx.media3.common.util.Assertions.checkArgument;
+
+import android.opengl.Matrix;
+import androidx.media3.common.util.UnstableApi;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+
+/** Scales the red, green, and blue color channels of a frame. */
+@UnstableApi
+public final class RgbAdjustment implements RgbaMatrix {
+
+  /** A builder for {@link RgbAdjustment} instances. */
+  public static final class Builder {
+    private float redScale;
+    private float greenScale;
+    private float blueScale;
+
+    /** Creates a new instance with default values. */
+    public Builder() {
+      redScale = 1;
+      greenScale = 1;
+      blueScale = 1;
+    }
+
+    /**
+     * Scales the red channel of the frame by {@param redScale}.
+     *
+     * @param redScale The scale to apply to the red channel. Needs to be non-negative and the
+     *     default value is {@code 1}.
+     */
+    @CanIgnoreReturnValue
+    public Builder setRedScale(float redScale) {
+      checkArgument(0 <= redScale, "Red scale needs to be non-negative.");
+      this.redScale = redScale;
+      return this;
+    }
+
+    /**
+     * Scales the green channel of the frame by {@param greenScale}.
+     *
+     * @param greenScale The scale to apply to the green channel. Needs to be non-negative and the
+     *     default value is {@code 1}.
+     */
+    @CanIgnoreReturnValue
+    public Builder setGreenScale(float greenScale) {
+      checkArgument(0 <= greenScale, "Green scale needs to be non-negative.");
+      this.greenScale = greenScale;
+      return this;
+    }
+
+    /**
+     * Scales the blue channel of the frame by {@param blueScale}.
+     *
+     * @param blueScale The scale to apply to the blue channel. Needs to be non-negative and the
+     *     default value is {@code 1}.
+     */
+    @CanIgnoreReturnValue
+    public Builder setBlueScale(float blueScale) {
+      checkArgument(0 <= blueScale, "Blue scale needs to be non-negative.");
+      this.blueScale = blueScale;
+      return this;
+    }
+
+    /** Creates a new {@link RgbAdjustment} instance. */
+    public RgbAdjustment build() {
+      float[] rgbaMatrix = new float[16];
+      Matrix.setIdentityM(rgbaMatrix, /* smOffset= */ 0);
+      Matrix.scaleM(
+          rgbaMatrix,
+          /* smOffset= */ 0,
+          /* x= */ redScale,
+          /* y= */ greenScale,
+          /* z= */ blueScale);
+
+      return new RgbAdjustment(rgbaMatrix);
+    }
+  }
+
+  private final float[] rgbaMatrix;
+
+  private RgbAdjustment(float[] rgbaMatrix) {
+    this.rgbaMatrix = rgbaMatrix;
+  }
+
+  @Override
+  public float[] getMatrix(long presentationTimeUs) {
+    return rgbaMatrix;
+  }
+}