Add static Grayscale and Inverted RGB Filter.

PiperOrigin-RevId: 471017440
(cherry picked from commit 859504230240eacd3255cdf6be987412a4ff6c69)

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

@@ -400,17 +400,9 @@ public final class GlEffectsFrameProcessorPixelTest {
   public void drawFrame_grayscaleAndIncreaseRedChannel_producesGrayscaleAndRedImage()
       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
-    // TODO(b/241240659): Use static grayscale filter from RgbFilter once it exists.
-    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
-    };
     ImmutableList<Effect> grayscaleThenIncreaseRed =
         ImmutableList.of(
-            (RgbMatrix) presentationTimeUs -> grayscaleMatrix,
-            new RgbAdjustment.Builder().setRedScale(3).build());
+            RgbFilter.createGrayscaleFilter(), new RgbAdjustment.Builder().setRedScale(3).build());
     setUpAndPrepareFirstFrame(DEFAULT_PIXEL_WIDTH_HEIGHT_RATIO, grayscaleThenIncreaseRed);
     Bitmap expectedBitmap =
         BitmapTestUtil.readBitmap(GRAYSCALE_THEN_INCREASE_RED_CHANNEL_PNG_ASSET_PATH);

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

@@ -57,8 +57,6 @@ public final class RgbAdjustmentPixelTest {
       "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";
 
   private final Context context = getApplicationContext();
 
@@ -102,12 +100,6 @@ public final class RgbAdjustmentPixelTest {
     GlUtil.destroyEglContext(eglDisplay, eglContext);
   }
 
-  private static RgbMatrixProcessor createRgbMatrixProcessor(Context context, float[] rgbMatrix)
-      throws FrameProcessingException {
-    return ((RgbMatrix) presentationTimeUs -> rgbMatrix)
-        .toGlTextureProcessor(context, /* useHdr= */ false);
-  }
-
   @Test
   public void drawFrame_identityMatrix_leavesFrameUnchanged() throws Exception {
     String testId = "drawFrame_identityMatrix";
@@ -218,33 +210,6 @@ public final class RgbAdjustmentPixelTest {
     assertThat(averagePixelAbsoluteDifference).isAtMost(MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE);
   }
 
-  @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[] 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
-    };
-    rgbMatrixProcessor = createRgbMatrixProcessor(/* context= */ context, grayscaleMatrix);
-    Pair<Integer, Integer> outputSize = rgbMatrixProcessor.configure(inputWidth, inputHeight);
-    Bitmap expectedBitmap = BitmapTestUtil.readBitmap(GRAYSCALE_PNG_ASSET_PATH);
-
-    rgbMatrixProcessor.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_removeRedGreenAndBlueValuesInAChain_producesBlackImage() throws Exception {
     String testId = "drawFrame_removeRedGreenBlueValuesInAChain";

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

@@ -0,0 +1,140 @@
+/*
+ * 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.checkNotNull;
+import static androidx.media3.effect.BitmapTestUtil.MAXIMUM_AVERAGE_PIXEL_ABSOLUTE_DIFFERENCE;
+import static androidx.test.core.app.ApplicationProvider.getApplicationContext;
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.opengl.EGLContext;
+import android.opengl.EGLDisplay;
+import android.opengl.EGLSurface;
+import android.util.Pair;
+import androidx.media3.common.FrameProcessingException;
+import androidx.media3.common.util.GlUtil;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+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 RgbFilter}.
+ *
+ * <p>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 RgbFilterPixelTest {
+  public static final String ORIGINAL_PNG_ASSET_PATH =
+      "media/bitmap/sample_mp4_first_frame/original.png";
+  public static final String GRAYSCALE_PNG_ASSET_PATH =
+      "media/bitmap/sample_mp4_first_frame/grayscale.png";
+  public static final String INVERT_PNG_ASSET_PATH =
+      "media/bitmap/sample_mp4_first_frame/invert.png";
+
+  private final Context context = getApplicationContext();
+
+  private @MonotonicNonNull EGLDisplay eglDisplay;
+  private @MonotonicNonNull EGLContext eglContext;
+  private @MonotonicNonNull SingleFrameGlTextureProcessor rgbMatrixProcessor;
+  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 (rgbMatrixProcessor != null) {
+      rgbMatrixProcessor.release();
+    }
+    GlUtil.destroyEglContext(eglDisplay, eglContext);
+  }
+
+  @Test
+  public void drawFrame_grayscale_producesGrayscaleImage() throws Exception {
+    String testId = "drawFrame_grayscale";
+    RgbMatrix grayscaleMatrix = RgbFilter.createGrayscaleFilter();
+    rgbMatrixProcessor = new RgbMatrixProcessor(context, grayscaleMatrix, /* useHdr= */ false);
+    Pair<Integer, Integer> outputSize = rgbMatrixProcessor.configure(inputWidth, inputHeight);
+    Bitmap expectedBitmap = BitmapTestUtil.readBitmap(GRAYSCALE_PNG_ASSET_PATH);
+
+    rgbMatrixProcessor.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_inverted_producesInvertedFrame() throws Exception {
+    String testId = "drawFrame_inverted";
+    RgbMatrix invertedMatrix = RgbFilter.createInvertedFilter();
+    rgbMatrixProcessor = new RgbMatrixProcessor(context, invertedMatrix, /* useHdr= */ false);
+    Pair<Integer, Integer> outputSize = rgbMatrixProcessor.configure(inputWidth, inputHeight);
+    Bitmap expectedBitmap = BitmapTestUtil.readBitmap(INVERT_PNG_ASSET_PATH);
+
+    rgbMatrixProcessor.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);
+  }
+}

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

@@ -96,7 +96,7 @@ public final class RgbAdjustment implements RgbMatrix {
   }
 
   @Override
-  public float[] getMatrix(long presentationTimeUs) {
+  public float[] getMatrix(long presentationTimeUs, boolean useHdr) {
     return rgbMatrix;
   }
 }

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

@@ -0,0 +1,99 @@
+/*
+ * 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.checkState;
+
+import android.content.Context;
+import androidx.media3.common.FrameProcessingException;
+import androidx.media3.common.util.UnstableApi;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+
+/** Provides common color filters. */
+@UnstableApi
+public class RgbFilter implements RgbMatrix {
+  private static final int COLOR_FILTER_GRAYSCALE_INDEX = 1;
+  private static final int COLOR_FILTER_INVERTED_INDEX = 2;
+
+  // Grayscale transformation matrix using the BT.709 luminance coefficients from
+  // https://en.wikipedia.org/wiki/Grayscale#Converting_colour_to_grayscale
+  private static final float[] FILTER_MATRIX_GRAYSCALE_SDR = {
+    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
+  };
+  // Grayscale transformation using the BT.2020 primary colors from
+  // https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.2020-2-201510-I!!PDF-E.pdf
+  // TODO(b/241240659): Add HDR tests once infrastructure supports it.
+  private static final float[] FILTER_MATRIX_GRAYSCALE_HDR = {
+    0.2627f, 0.2627f, 0.2627f, 0, 0.6780f, 0.6780f, 0.6780f, 0, 0.0593f, 0.0593f, 0.0593f, 0, 0, 0,
+    0, 1
+  };
+  // Inverted filter uses the transformation R' = -R + 1 = 1 - R.
+  private static final float[] FILTER_MATRIX_INVERTED = {
+    -1, 0, 0, 0, 0, -1, 0, 0, 0, 0, -1, 0, 1, 1, 1, 1
+  };
+
+  private final int colorFilter;
+  /**
+   * Ensures that the usage of HDR is consistent. {@code null} indicates that HDR has not yet been
+   * set.
+   */
+  private @MonotonicNonNull Boolean useHdr;
+
+  /** Creates a new grayscale {@code RgbFilter} instance. */
+  public static RgbFilter createGrayscaleFilter() {
+    return new RgbFilter(COLOR_FILTER_GRAYSCALE_INDEX);
+  }
+
+  /** Creates a new inverted {@code RgbFilter} instance. */
+  public static RgbFilter createInvertedFilter() {
+    return new RgbFilter(COLOR_FILTER_INVERTED_INDEX);
+  }
+
+  private RgbFilter(int colorFilter) {
+    this.colorFilter = colorFilter;
+  }
+
+  private void checkForConsistentHdrSetting(boolean useHdr) {
+    if (this.useHdr == null) {
+      this.useHdr = useHdr;
+    } else {
+      checkState(this.useHdr == useHdr, "Changing HDR setting is not supported.");
+    }
+  }
+
+  @Override
+  public float[] getMatrix(long presentationTimeUs, boolean useHdr) {
+    checkForConsistentHdrSetting(useHdr);
+    switch (colorFilter) {
+      case COLOR_FILTER_GRAYSCALE_INDEX:
+        return useHdr ? FILTER_MATRIX_GRAYSCALE_HDR : FILTER_MATRIX_GRAYSCALE_SDR;
+      case COLOR_FILTER_INVERTED_INDEX:
+        return FILTER_MATRIX_INVERTED;
+      default:
+        // Should never happen.
+        throw new IllegalStateException("Invalid color filter " + colorFilter);
+    }
+  }
+
+  @Override
+  public RgbMatrixProcessor toGlTextureProcessor(Context context, boolean useHdr)
+      throws FrameProcessingException {
+    checkForConsistentHdrSetting(useHdr);
+    return new RgbMatrixProcessor(context, /* rgbMatrix= */ this, useHdr);
+  }
+}

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

@@ -29,8 +29,14 @@ public interface RgbMatrix extends GlEffect {
   /**
    * Returns the 4x4 RGB transformation {@linkplain android.opengl.Matrix matrix} to apply to the
    * color values of each pixel in the frame with the given timestamp.
+   *
+   * @param presentationTimeUs The timestamp of the frame to apply the matrix on.
+   * @param useHdr If {@code true}, colors will be in linear RGB BT.2020. If {@code false}, colors
+   *     will be in gamma RGB BT.709. Must be consistent with {@code useHdr} in {@link
+   *     #toGlTextureProcessor(Context, boolean)}.
+   * @return The {@code RgbMatrix} to apply to the frame.
    */
-  float[] getMatrix(long presentationTimeUs);
+  float[] getMatrix(long presentationTimeUs, boolean useHdr);
 
   @Override
   default RgbMatrixProcessor toGlTextureProcessor(Context context, boolean useHdr)

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

@@ -39,6 +39,7 @@ import java.io.IOException;
 
   private final GlProgram glProgram;
   private final ImmutableList<RgbMatrix> rgbMatrices;
+  private final boolean useHdr;
 
   // TODO(b/239757183): Merge RgbMatrixProcessor with MatrixTransformationProcessor.
   /**
@@ -70,6 +71,7 @@ import java.io.IOException;
       throws FrameProcessingException {
     super(useHdr);
     this.rgbMatrices = rgbMatrices;
+    this.useHdr = useHdr;
 
     try {
       glProgram = new GlProgram(context, VERTEX_SHADER_PATH, FRAGMENT_SHADER_PATH);
@@ -95,7 +97,7 @@ import java.io.IOException;
   }
 
   private static float[] createCompositeRgbaMatrixArray(
-      ImmutableList<RgbMatrix> rgbMatrices, long presentationTimeUs) {
+      ImmutableList<RgbMatrix> rgbMatrices, boolean useHdr, long presentationTimeUs) {
     float[] tempResultMatrix = new float[16];
     float[] compositeRgbaMatrix = new float[16];
     Matrix.setIdentityM(compositeRgbaMatrix, /* smOffset= */ 0);
@@ -104,7 +106,7 @@ import java.io.IOException;
       Matrix.multiplyMM(
           /* result= */ tempResultMatrix,
           /* resultOffset= */ 0,
-          /* lhs= */ rgbMatrices.get(i).getMatrix(presentationTimeUs),
+          /* lhs= */ rgbMatrices.get(i).getMatrix(presentationTimeUs, useHdr),
           /* lhsOffset= */ 0,
           /* rhs= */ compositeRgbaMatrix,
           /* rhsOffset= */ 0);
@@ -122,7 +124,8 @@ import java.io.IOException;
   @Override
   public void drawFrame(int inputTexId, long presentationTimeUs) throws FrameProcessingException {
     // TODO(b/239431666): Add caching for compacting Matrices.
-    float[] rgbMatrixArray = createCompositeRgbaMatrixArray(rgbMatrices, presentationTimeUs);
+    float[] rgbMatrixArray =
+        createCompositeRgbaMatrixArray(rgbMatrices, useHdr, presentationTimeUs);
     try {
       glProgram.use();
       glProgram.setSamplerTexIdUniform("uTexSampler", inputTexId, /* texUnitIndex= */ 0);