Android: Add tests for VideoFrame.Buffer.toI420() and cropAndScale()

This CL adds tests that are primarily targeting
VideoFrame.Buffer.toI420() and cropAndScale(), but includes the whole
chain for YuvConverter, GlRectDrawer, and VideoFrameDrawer.

It also includes a couple of fixes to bugs that were exposed by the new
tests.

Bug: webrtc:9186, webrtc:9391
Change-Id: I5eb62979a8fd8def28c3cb2e82dcede57c42216f
Reviewed-on: https://webrtc-review.googlesource.com/83163
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23611}

sdk/android/BUILD.gn

@@ -1048,6 +1048,7 @@ if (rtc_include_tests) {
       "instrumentationtests/src/org/webrtc/EglRendererTest.java",
       "instrumentationtests/src/org/webrtc/FileVideoCapturerTest.java",
       "instrumentationtests/src/org/webrtc/GlRectDrawerTest.java",
+      "instrumentationtests/src/org/webrtc/VideoFrameBufferTest.java",
       "instrumentationtests/src/org/webrtc/HardwareVideoDecoderTest.java",
       "instrumentationtests/src/org/webrtc/HardwareVideoEncoderTest.java",
       "instrumentationtests/src/org/webrtc/MediaCodecVideoEncoderTest.java",

sdk/android/api/org/webrtc/JavaI420Buffer.java

@@ -39,6 +39,15 @@ public class JavaI420Buffer implements VideoFrame.I420Buffer {
     this.refCountDelegate = new RefCountDelegate(releaseCallback);
   }
 
+  private static void checkCapacity(ByteBuffer data, int width, int height, int stride) {
+    // The last row does not necessarily need padding.
+    final int minCapacity = stride * (height - 1) + width;
+    if (data.capacity() < minCapacity) {
+      throw new IllegalArgumentException(
+          "Buffer must be at least " + minCapacity + " bytes, but was " + data.capacity());
+    }
+  }
+
   /** Wraps existing ByteBuffers into JavaI420Buffer object without copying the contents. */
   public static JavaI420Buffer wrap(int width, int height, ByteBuffer dataY, int strideY,
       ByteBuffer dataU, int strideU, ByteBuffer dataV, int strideV, Runnable releaseCallback) {
@@ -55,19 +64,11 @@ public class JavaI420Buffer implements VideoFrame.I420Buffer {
     dataU = dataU.slice();
     dataV = dataV.slice();
 
+    final int chromaWidth = (width + 1) / 2;
     final int chromaHeight = (height + 1) / 2;
-    final int minCapacityY = strideY * height;
-    final int minCapacityU = strideU * chromaHeight;
-    final int minCapacityV = strideV * chromaHeight;
-    if (dataY.capacity() < minCapacityY) {
-      throw new IllegalArgumentException("Y-buffer must be at least " + minCapacityY + " bytes.");
-    }
-    if (dataU.capacity() < minCapacityU) {
-      throw new IllegalArgumentException("U-buffer must be at least " + minCapacityU + " bytes.");
-    }
-    if (dataV.capacity() < minCapacityV) {
-      throw new IllegalArgumentException("V-buffer must be at least " + minCapacityV + " bytes.");
-    }
+    checkCapacity(dataY, width, height, strideY);
+    checkCapacity(dataU, chromaWidth, chromaHeight, strideU);
+    checkCapacity(dataV, chromaWidth, chromaHeight, strideV);
 
     return new JavaI420Buffer(
         width, height, dataY, strideY, dataU, strideU, dataV, strideV, releaseCallback);

sdk/android/api/org/webrtc/TextureBufferImpl.java

@@ -85,7 +85,10 @@ public class TextureBufferImpl implements VideoFrame.TextureBuffer {
   public VideoFrame.Buffer cropAndScale(
       int cropX, int cropY, int cropWidth, int cropHeight, int scaleWidth, int scaleHeight) {
     final Matrix newMatrix = new Matrix(transformMatrix);
-    newMatrix.preTranslate(cropX / (float) width, cropY / (float) height);
+    // In WebRTC, Y=0 is the top row, while in OpenGL Y=0 is the bottom row. This means that the Y
+    // direction is effectively reversed.
+    final int cropYFromBottom = height - (cropY + cropHeight);
+    newMatrix.preTranslate(cropX / (float) width, cropYFromBottom / (float) height);
     newMatrix.preScale(cropWidth / (float) width, cropHeight / (float) height);
 
     retain();

sdk/android/api/org/webrtc/VideoFrame.java

@@ -204,9 +204,8 @@ public class VideoFrame implements RefCounted {
       dataV.position(cropX / 2 + cropY / 2 * buffer.getStrideV());
 
       buffer.retain();
-      return JavaI420Buffer.wrap(buffer.getWidth(), buffer.getHeight(), dataY.slice(),
-          buffer.getStrideY(), dataU.slice(), buffer.getStrideU(), dataV.slice(),
-          buffer.getStrideV(), buffer::release);
+      return JavaI420Buffer.wrap(scaleWidth, scaleHeight, dataY.slice(), buffer.getStrideY(),
+          dataU.slice(), buffer.getStrideU(), dataV.slice(), buffer.getStrideV(), buffer::release);
     }
 
     JavaI420Buffer newBuffer = JavaI420Buffer.allocate(scaleWidth, scaleHeight);

sdk/android/api/org/webrtc/YuvConverter.java

@@ -286,7 +286,7 @@ public class YuvConverter {
     // Y'UV444 to RGB888, see
     // https://en.wikipedia.org/wiki/YUV#Y.27UV444_to_RGB888_conversion.
     // We use the ITU-R coefficients for U and V */
-    GLES20.glUniform4f(coeffsLoc, 0.299f, 0.587f, 0.114f, 0.0f);
+    GLES20.glUniform4f(coeffsLoc, 0.2987856f, 0.5871095f, 0.1141049f, 0.0f);
     GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
 
     // Draw U
@@ -294,12 +294,12 @@ public class YuvConverter {
     // Matrix * (1;0;0;0) / (width / 2). Note that opengl uses column major order.
     GLES20.glUniform2f(
         xUnitLoc, 2.0f * transformMatrix[0] / width, 2.0f * transformMatrix[1] / width);
-    GLES20.glUniform4f(coeffsLoc, -0.169f, -0.331f, 0.499f, 0.5f);
+    GLES20.glUniform4f(coeffsLoc, -0.168805420f, -0.3317003f, 0.5005057f, 0.5f);
     GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
 
     // Draw V
     GLES20.glViewport(stride / 8, height, uv_width, uv_height);
-    GLES20.glUniform4f(coeffsLoc, 0.499f, -0.418f, -0.0813f, 0.5f);
+    GLES20.glUniform4f(coeffsLoc, 0.4997964f, -0.4184672f, -0.0813292f, 0.5f);
     GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
 
     GLES20.glReadPixels(

sdk/android/instrumentationtests/src/org/webrtc/VideoFrameBufferTest.java

@@ -0,0 +1,562 @@
+/*
+ *  Copyright 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.
+ */
+
+package org.webrtc;
+
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+
+import android.graphics.Matrix;
+import android.graphics.SurfaceTexture;
+import android.opengl.GLES20;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.filters.SmallTest;
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import org.chromium.base.test.params.BaseJUnit4RunnerDelegate;
+import org.chromium.base.test.params.ParameterAnnotations.ClassParameter;
+import org.chromium.base.test.params.ParameterAnnotations.UseRunnerDelegate;
+import org.chromium.base.test.params.ParameterSet;
+import org.chromium.base.test.params.ParameterizedRunner;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * Test VideoFrame buffers of different kind of formats: I420, RGB, OES, NV12, NV21, and verify
+ * toI420() and cropAndScale() behavior. Creating RGB/OES textures involves VideoFrameDrawer and
+ * GlRectDrawer and we are testing the full chain I420 -> OES/RGB texture -> I420, with and without
+ * cropping in the middle. Reading textures back to I420 also exercises the YuvConverter code.
+ */
+@RunWith(ParameterizedRunner.class)
+@UseRunnerDelegate(BaseJUnit4RunnerDelegate.class)
+public class VideoFrameBufferTest {
+  /**
+   * These tests are parameterized on this enum which represents the different VideoFrame.Buffers.
+   */
+  private static enum BufferType { I420, RGB_TEXTURE, OES_TEXTURE, NV21, NV12 }
+
+  @ClassParameter private static List<ParameterSet> CLASS_PARAMS = new ArrayList<>();
+
+  static {
+    for (BufferType bufferType : BufferType.values()) {
+      // The parameterization framework can not send Enums, so we pass it as a string instead.
+      CLASS_PARAMS.add(new ParameterSet().value(bufferType.name()).name(bufferType.name()));
+    }
+  }
+
+  @BeforeClass
+  public static void setUp() {
+    // Needed for JniCommon.nativeAllocateByteBuffer() to work, which is used from JavaI420Buffer.
+    System.loadLibrary("jingle_peerconnection_so");
+  }
+
+  private final BufferType bufferType;
+
+  public VideoFrameBufferTest(String bufferTypeName) {
+    // Parse the string back to an enum.
+    bufferType = BufferType.valueOf(bufferTypeName);
+  }
+
+  /**
+   * Create a VideoFrame.Buffer of the given type with the same pixel content as the given I420
+   * buffer.
+   */
+  private static VideoFrame.Buffer createBufferWithType(
+      BufferType bufferType, VideoFrame.I420Buffer i420Buffer) {
+    switch (bufferType) {
+      case I420:
+        return i420Buffer.toI420();
+      case RGB_TEXTURE:
+        return createRgbTextureBuffer(/* eglContext= */ null, i420Buffer);
+      case OES_TEXTURE:
+        return createOesTextureBuffer(/* eglContext= */ null, i420Buffer);
+      case NV21:
+        return createNV21Buffer(i420Buffer);
+      case NV12:
+        return createNV12Buffer(i420Buffer);
+      default:
+        throw new IllegalArgumentException("Unknown buffer type: " + bufferType);
+    }
+  }
+
+  private VideoFrame.Buffer createBufferToTest(VideoFrame.I420Buffer i420Buffer) {
+    return createBufferWithType(this.bufferType, i420Buffer);
+  }
+
+  /**
+   * Creates a 16x16 I420 buffer that varies smoothly and spans all RGB values.
+   */
+  public static VideoFrame.I420Buffer createTestI420Buffer() {
+    final int width = 16;
+    final int height = 16;
+    final int[] yData = new int[] {164, 170, 176, 182, 188, 194, 200, 206, 213, 218, 225, 231, 237,
+        243, 249, 255, 153, 159, 165, 171, 177, 183, 189, 195, 201, 207, 213, 220, 226, 232, 238,
+        244, 142, 148, 154, 160, 166, 172, 178, 184, 191, 196, 203, 209, 215, 221, 227, 233, 131,
+        137, 143, 149, 155, 161, 167, 174, 180, 186, 192, 198, 204, 210, 216, 222, 120, 126, 132,
+        138, 145, 151, 157, 163, 169, 175, 181, 187, 193, 199, 205, 211, 109, 115, 121, 128, 133,
+        140, 146, 152, 158, 164, 170, 176, 182, 188, 194, 200, 99, 104, 111, 117, 123, 129, 135,
+        141, 147, 153, 159, 165, 171, 177, 183, 189, 87, 94, 100, 106, 112, 118, 124, 130, 136, 142,
+        148, 154, 160, 166, 172, 178, 77, 83, 89, 95, 101, 107, 113, 119, 125, 131, 137, 143, 149,
+        155, 161, 167, 66, 72, 78, 84, 90, 96, 102, 108, 114, 120, 126, 132, 138, 144, 150, 156, 55,
+        61, 67, 73, 79, 85, 91, 97, 103, 109, 115, 121, 127, 133, 139, 145, 44, 50, 56, 62, 68, 74,
+        80, 86, 92, 98, 104, 110, 116, 122, 128, 134, 33, 39, 45, 51, 57, 63, 69, 75, 81, 87, 93,
+        99, 105, 111, 117, 123, 22, 28, 34, 40, 46, 52, 58, 64, 70, 76, 82, 88, 94, 100, 106, 113,
+        11, 17, 23, 29, 35, 41, 47, 53, 59, 65, 71, 77, 83, 89, 96, 102, 0, 6, 12, 18, 24, 30, 36,
+        42, 48, 54, 60, 66, 72, 79, 85, 91};
+    final int[] uData = new int[] {108, 111, 114, 117, 119, 122, 125, 128, 111, 114, 117, 119, 122,
+        125, 128, 130, 114, 117, 119, 122, 125, 128, 130, 133, 117, 119, 122, 125, 128, 130, 133,
+        136, 119, 122, 125, 128, 130, 133, 136, 139, 122, 125, 128, 130, 133, 136, 139, 141, 125,
+        128, 130, 133, 136, 139, 141, 144, 128, 130, 133, 136, 139, 141, 144, 147};
+    final int[] vData = new int[] {18, 34, 49, 65, 81, 96, 112, 127, 34, 49, 65, 81, 96, 112, 128,
+        143, 49, 65, 81, 96, 112, 127, 143, 159, 65, 81, 96, 112, 127, 143, 159, 174, 81, 96, 112,
+        128, 143, 159, 174, 190, 96, 112, 128, 143, 159, 174, 190, 206, 112, 127, 143, 159, 174,
+        190, 205, 221, 127, 143, 159, 174, 190, 205, 221, 237};
+    return JavaI420Buffer.wrap(width, height, toByteBuffer(yData),
+        /* strideY= */ width, toByteBuffer(uData), /* strideU= */ width / 2, toByteBuffer(vData),
+        /* strideV= */ width / 2,
+        /* releaseCallback= */ null);
+  }
+
+  /**
+   * Create an RGB texture buffer available in |eglContext| with the same pixel content as the given
+   * I420 buffer.
+   */
+  public static VideoFrame.TextureBuffer createRgbTextureBuffer(
+      EglBase.Context eglContext, VideoFrame.I420Buffer i420Buffer) {
+    final int width = i420Buffer.getWidth();
+    final int height = i420Buffer.getHeight();
+
+    final HandlerThread renderThread = new HandlerThread("RGB texture thread");
+    renderThread.start();
+    final Handler renderThreadHandler = new Handler(renderThread.getLooper());
+    return ThreadUtils.invokeAtFrontUninterruptibly(renderThreadHandler, () -> {
+      // Create EGL base with a pixel buffer as display output.
+      final EglBase eglBase = EglBase.create(eglContext, EglBase.CONFIG_PIXEL_BUFFER);
+      eglBase.createDummyPbufferSurface();
+      eglBase.makeCurrent();
+
+      final GlTextureFrameBuffer textureFrameBuffer = new GlTextureFrameBuffer(GLES20.GL_RGBA);
+      textureFrameBuffer.setSize(width, height);
+
+      GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, textureFrameBuffer.getFrameBufferId());
+      drawI420Buffer(i420Buffer);
+      GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
+
+      final YuvConverter yuvConverter = new YuvConverter();
+      return new TextureBufferImpl(width, height, VideoFrame.TextureBuffer.Type.RGB,
+          textureFrameBuffer.getTextureId(),
+          /* transformMatrix= */ new Matrix(), renderThreadHandler, yuvConverter,
+          /* releaseCallback= */ () -> renderThreadHandler.post(() -> {
+            textureFrameBuffer.release();
+            yuvConverter.release();
+            eglBase.release();
+            renderThread.quit();
+          }));
+    });
+  }
+
+  /**
+   * Create an OES texture buffer available in |eglContext| with the same pixel content as the given
+   * I420 buffer.
+   */
+  public static VideoFrame.TextureBuffer createOesTextureBuffer(
+      EglBase.Context eglContext, VideoFrame.I420Buffer i420Buffer) {
+    final int width = i420Buffer.getWidth();
+    final int height = i420Buffer.getHeight();
+
+    // Create resources for generating OES textures.
+    final SurfaceTextureHelper surfaceTextureHelper =
+        SurfaceTextureHelper.create("SurfaceTextureHelper test", eglContext);
+    final SurfaceTexture surfaceTexture = surfaceTextureHelper.getSurfaceTexture();
+    surfaceTexture.setDefaultBufferSize(width, height);
+
+    final HandlerThread renderThread = new HandlerThread("OES texture thread");
+    renderThread.start();
+    final Handler renderThreadHandler = new Handler(renderThread.getLooper());
+    final VideoFrame.TextureBuffer oesBuffer =
+        ThreadUtils.invokeAtFrontUninterruptibly(renderThreadHandler, () -> {
+          // Create EGL base with the SurfaceTexture as display output.
+          final EglBase eglBase = EglBase.create(eglContext, EglBase.CONFIG_PLAIN);
+          eglBase.createSurface(surfaceTexture);
+          eglBase.makeCurrent();
+          assertEquals(width, eglBase.surfaceWidth());
+          assertEquals(height, eglBase.surfaceHeight());
+
+          final SurfaceTextureHelperTest.MockTextureListener listener =
+              new SurfaceTextureHelperTest.MockTextureListener();
+          surfaceTextureHelper.startListening(listener);
+
+          // Draw the frame and block until an OES texture is delivered.
+          drawI420Buffer(i420Buffer);
+          eglBase.swapBuffers();
+          listener.waitForNewFrame();
+          surfaceTextureHelper.stopListening();
+          surfaceTextureHelper.dispose();
+
+          return surfaceTextureHelper.createTextureBuffer(width, height,
+              RendererCommon.convertMatrixToAndroidGraphicsMatrix(listener.transformMatrix));
+        });
+
+    // Wrap |oesBuffer| to quit |renderThread| once |oesBuffer| is released.
+    return new VideoFrame.TextureBuffer() {
+      private final RefCountDelegate refCountDelegate = new RefCountDelegate(() -> {
+        oesBuffer.release();
+        renderThread.quit();
+      });
+
+      @Override
+      public void retain() {
+        refCountDelegate.retain();
+      }
+
+      @Override
+      public void release() {
+        refCountDelegate.release();
+      }
+
+      @Override
+      public VideoFrame.TextureBuffer.Type getType() {
+        return oesBuffer.getType();
+      }
+
+      @Override
+      public int getTextureId() {
+        return oesBuffer.getTextureId();
+      }
+
+      @Override
+      public Matrix getTransformMatrix() {
+        return oesBuffer.getTransformMatrix();
+      }
+
+      @Override
+      public int getWidth() {
+        return oesBuffer.getWidth();
+      }
+
+      @Override
+      public int getHeight() {
+        return oesBuffer.getHeight();
+      }
+
+      @Override
+      public VideoFrame.I420Buffer toI420() {
+        return oesBuffer.toI420();
+      }
+
+      @Override
+      public VideoFrame.Buffer cropAndScale(
+          int cropX, int cropY, int cropWidth, int cropHeight, int scaleWidth, int scaleHeight) {
+        return oesBuffer.cropAndScale(cropX, cropY, cropWidth, cropHeight, scaleWidth, scaleHeight);
+      }
+    };
+  }
+
+  /** Create an NV21Buffer with the same pixel content as the given I420 buffer. */
+  public static NV21Buffer createNV21Buffer(VideoFrame.I420Buffer i420Buffer) {
+    final int width = i420Buffer.getWidth();
+    final int height = i420Buffer.getHeight();
+    final int chromaStride = width;
+    final int chromaWidth = (width + 1) / 2;
+    final int chromaHeight = (height + 1) / 2;
+    final int ySize = width * height;
+
+    final ByteBuffer nv21Buffer = ByteBuffer.allocateDirect(ySize + chromaStride * chromaHeight);
+    // We don't care what the array offset is since we only want an array that is direct.
+    @SuppressWarnings("ByteBufferBackingArray") final byte[] nv21Data = nv21Buffer.array();
+
+    for (int y = 0; y < height; ++y) {
+      for (int x = 0; x < width; ++x) {
+        final byte yValue = i420Buffer.getDataY().get(y * i420Buffer.getStrideY() + x);
+        nv21Data[y * width + x] = yValue;
+      }
+    }
+    for (int y = 0; y < chromaHeight; ++y) {
+      for (int x = 0; x < chromaWidth; ++x) {
+        final byte uValue = i420Buffer.getDataU().get(y * i420Buffer.getStrideU() + x);
+        final byte vValue = i420Buffer.getDataV().get(y * i420Buffer.getStrideV() + x);
+        nv21Data[ySize + y * chromaStride + 2 * x + 0] = vValue;
+        nv21Data[ySize + y * chromaStride + 2 * x + 1] = uValue;
+      }
+    }
+    return new NV21Buffer(nv21Data, width, height, /* releaseCallback= */ null);
+  }
+
+  /** Create an NV12Buffer with the same pixel content as the given I420 buffer. */
+  public static NV12Buffer createNV12Buffer(VideoFrame.I420Buffer i420Buffer) {
+    final int width = i420Buffer.getWidth();
+    final int height = i420Buffer.getHeight();
+    final int chromaStride = width;
+    final int chromaWidth = (width + 1) / 2;
+    final int chromaHeight = (height + 1) / 2;
+    final int ySize = width * height;
+
+    final ByteBuffer nv12Buffer = ByteBuffer.allocateDirect(ySize + chromaStride * chromaHeight);
+
+    for (int y = 0; y < height; ++y) {
+      for (int x = 0; x < width; ++x) {
+        final byte yValue = i420Buffer.getDataY().get(y * i420Buffer.getStrideY() + x);
+        nv12Buffer.put(y * width + x, yValue);
+      }
+    }
+    for (int y = 0; y < chromaHeight; ++y) {
+      for (int x = 0; x < chromaWidth; ++x) {
+        final byte uValue = i420Buffer.getDataU().get(y * i420Buffer.getStrideU() + x);
+        final byte vValue = i420Buffer.getDataV().get(y * i420Buffer.getStrideV() + x);
+        nv12Buffer.put(ySize + y * chromaStride + 2 * x + 0, uValue);
+        nv12Buffer.put(ySize + y * chromaStride + 2 * x + 1, vValue);
+      }
+    }
+    return new NV12Buffer(width, height, /* stride= */ width, /* sliceHeight= */ height, nv12Buffer,
+        /* releaseCallback */ null);
+  }
+
+  /** Print the ByteBuffer plane to the StringBuilder. */
+  private static void printPlane(
+      StringBuilder stringBuilder, int width, int height, ByteBuffer plane, int stride) {
+    for (int y = 0; y < height; ++y) {
+      for (int x = 0; x < width; ++x) {
+        final int value = plane.get(y * stride + x) & 0xFF;
+        if (x != 0) {
+          stringBuilder.append(", ");
+        }
+        stringBuilder.append(value);
+      }
+      stringBuilder.append("\n");
+    }
+  }
+
+  /** Convert the pixel content of an I420 buffer to a string representation. */
+  private static String i420BufferToString(VideoFrame.I420Buffer buffer) {
+    final StringBuilder stringBuilder = new StringBuilder();
+    stringBuilder.append(
+        "I420 buffer with size: " + buffer.getWidth() + "x" + buffer.getHeight() + ".\n");
+    stringBuilder.append("Y-plane:\n");
+    printPlane(stringBuilder, buffer.getWidth(), buffer.getHeight(), buffer.getDataY(),
+        buffer.getStrideY());
+    final int chromaWidth = (buffer.getWidth() + 1) / 2;
+    final int chromaHeight = (buffer.getHeight() + 1) / 2;
+    stringBuilder.append("U-plane:\n");
+    printPlane(stringBuilder, chromaWidth, chromaHeight, buffer.getDataU(), buffer.getStrideU());
+    stringBuilder.append("V-plane:\n");
+    printPlane(stringBuilder, chromaWidth, chromaHeight, buffer.getDataV(), buffer.getStrideV());
+    return stringBuilder.toString();
+  }
+
+  /**
+   * Assert that the given I420 buffers are almost identical, allowing for some difference due to
+   * numerical errors. It has limits for both overall PSNR and maximum individual pixel difference.
+   */
+  public static void assertAlmostEqualI420Buffers(
+      VideoFrame.I420Buffer bufferA, VideoFrame.I420Buffer bufferB) {
+    final int diff = maxDiff(bufferA, bufferB);
+    assertThat("Pixel difference too high: " + diff + "."
+            + "\nBuffer A: " + i420BufferToString(bufferA)
+            + "Buffer B: " + i420BufferToString(bufferB),
+        diff, lessThanOrEqualTo(4));
+    final double psnr = calculatePsnr(bufferA, bufferB);
+    assertThat("PSNR too low: " + psnr + "."
+            + "\nBuffer A: " + i420BufferToString(bufferA)
+            + "Buffer B: " + i420BufferToString(bufferB),
+        psnr, greaterThanOrEqualTo(50.0));
+  }
+
+  /** Returns a flattened list of pixel differences for two ByteBuffer planes. */
+  private static List<Integer> getPixelDiffs(
+      int width, int height, ByteBuffer planeA, int strideA, ByteBuffer planeB, int strideB) {
+    List<Integer> res = new ArrayList<>();
+    for (int y = 0; y < height; ++y) {
+      for (int x = 0; x < width; ++x) {
+        final int valueA = planeA.get(y * strideA + x) & 0xFF;
+        final int valueB = planeB.get(y * strideB + x) & 0xFF;
+        res.add(Math.abs(valueA - valueB));
+      }
+    }
+    return res;
+  }
+
+  /** Returns a flattened list of pixel differences for two I420 buffers. */
+  private static List<Integer> getPixelDiffs(
+      VideoFrame.I420Buffer bufferA, VideoFrame.I420Buffer bufferB) {
+    assertEquals(bufferA.getWidth(), bufferB.getWidth());
+    assertEquals(bufferA.getHeight(), bufferB.getHeight());
+    final int width = bufferA.getWidth();
+    final int height = bufferA.getHeight();
+    final int chromaWidth = (width + 1) / 2;
+    final int chromaHeight = (height + 1) / 2;
+    final List<Integer> diffs = getPixelDiffs(width, height, bufferA.getDataY(),
+        bufferA.getStrideY(), bufferB.getDataY(), bufferB.getStrideY());
+    diffs.addAll(getPixelDiffs(chromaWidth, chromaHeight, bufferA.getDataU(), bufferA.getStrideU(),
+        bufferB.getDataU(), bufferB.getStrideU()));
+    diffs.addAll(getPixelDiffs(chromaWidth, chromaHeight, bufferA.getDataV(), bufferA.getStrideV(),
+        bufferB.getDataV(), bufferB.getStrideV()));
+    return diffs;
+  }
+
+  /** Returns the maximum pixel difference from any of the Y/U/V planes in the given buffers. */
+  private static int maxDiff(VideoFrame.I420Buffer bufferA, VideoFrame.I420Buffer bufferB) {
+    return Collections.max(getPixelDiffs(bufferA, bufferB));
+  }
+
+  /**
+   * Returns the PSNR given a sum of squared error and the number of measurements that were added.
+   */
+  private static double sseToPsnr(long sse, int count) {
+    if (sse == 0) {
+      return Double.POSITIVE_INFINITY;
+    }
+    final double meanSquaredError = (double) sse / (double) count;
+    final double maxPixelValue = 255.0;
+    return 10.0 * Math.log10(maxPixelValue * maxPixelValue / meanSquaredError);
+  }
+
+  /** Returns the PSNR of the given I420 buffers. */
+  private static double calculatePsnr(
+      VideoFrame.I420Buffer bufferA, VideoFrame.I420Buffer bufferB) {
+    final List<Integer> pixelDiffs = getPixelDiffs(bufferA, bufferB);
+    long sse = 0;
+    for (int pixelDiff : pixelDiffs) {
+      sse += pixelDiff * pixelDiff;
+    }
+    return sseToPsnr(sse, pixelDiffs.size());
+  }
+
+  /**
+   * Convert an int array to a byte array and make sure the values are within the range [0, 255].
+   */
+  private static byte[] toByteArray(int[] array) {
+    final byte[] res = new byte[array.length];
+    for (int i = 0; i < array.length; ++i) {
+      final int value = array[i];
+      assertThat(value, greaterThanOrEqualTo(0));
+      assertThat(value, lessThanOrEqualTo(255));
+      res[i] = (byte) value;
+    }
+    return res;
+  }
+
+  /** Convert a byte array to a direct ByteBuffer. */
+  private static ByteBuffer toByteBuffer(int[] array) {
+    final ByteBuffer buffer = ByteBuffer.allocateDirect(array.length);
+    buffer.put(toByteArray(array));
+    buffer.rewind();
+    return buffer;
+  }
+
+  /**
+   * Draw an I420 buffer on the currently bound frame buffer, allocating and releasing any
+   * resources necessary.
+   */
+  private static void drawI420Buffer(VideoFrame.I420Buffer i420Buffer) {
+    final GlRectDrawer drawer = new GlRectDrawer();
+    final VideoFrameDrawer videoFrameDrawer = new VideoFrameDrawer();
+    videoFrameDrawer.drawFrame(
+        new VideoFrame(i420Buffer, /* rotation= */ 0, /* timestampNs= */ 0), drawer);
+    videoFrameDrawer.release();
+    drawer.release();
+  }
+
+  /**
+   * Helper function that tests cropAndScale() with the given cropping and scaling parameters, and
+   * compares the pixel content against a reference I420 buffer.
+   */
+  private void testCropAndScale(
+      int cropX, int cropY, int cropWidth, int cropHeight, int scaleWidth, int scaleHeight) {
+    final VideoFrame.I420Buffer referenceI420Buffer = createTestI420Buffer();
+    final VideoFrame.Buffer bufferToTest = createBufferToTest(referenceI420Buffer);
+
+    final VideoFrame.Buffer croppedReferenceBuffer = referenceI420Buffer.cropAndScale(
+        cropX, cropY, cropWidth, cropHeight, scaleWidth, scaleHeight);
+    referenceI420Buffer.release();
+    final VideoFrame.I420Buffer croppedReferenceI420Buffer = croppedReferenceBuffer.toI420();
+    croppedReferenceBuffer.release();
+
+    final VideoFrame.Buffer croppedBufferToTest =
+        bufferToTest.cropAndScale(cropX, cropY, cropWidth, cropHeight, scaleWidth, scaleHeight);
+    bufferToTest.release();
+
+    final VideoFrame.I420Buffer croppedOutputI420Buffer = croppedBufferToTest.toI420();
+    croppedBufferToTest.release();
+
+    assertAlmostEqualI420Buffers(croppedReferenceI420Buffer, croppedOutputI420Buffer);
+    croppedReferenceI420Buffer.release();
+    croppedOutputI420Buffer.release();
+  }
+
+  @Test
+  @SmallTest
+  /** Test calling toI420() and comparing pixel content against I420 reference. */
+  public void testToI420() {
+    final VideoFrame.I420Buffer referenceI420Buffer = createTestI420Buffer();
+    final VideoFrame.Buffer bufferToTest = createBufferToTest(referenceI420Buffer);
+
+    final VideoFrame.I420Buffer outputI420Buffer = bufferToTest.toI420();
+    bufferToTest.release();
+
+    assertAlmostEqualI420Buffers(referenceI420Buffer, outputI420Buffer);
+    referenceI420Buffer.release();
+    outputI420Buffer.release();
+  }
+
+  @Test
+  @SmallTest
+  /** Pure 2x scaling with no cropping. */
+  public void testScale2x() {
+    testCropAndScale(0 /* cropX= */, 0 /* cropY= */, /* cropWidth= */ 16, /* cropHeight= */ 16,
+        /* scaleWidth= */ 8, /* scaleHeight= */ 8);
+  }
+
+  @Test
+  @SmallTest
+  /** Test cropping only X direction, with no scaling. */
+  public void testCropX() {
+    testCropAndScale(8 /* cropX= */, 0 /* cropY= */, /* cropWidth= */ 8, /* cropHeight= */ 16,
+        /* scaleWidth= */ 8, /* scaleHeight= */ 16);
+  }
+
+  @Test
+  @SmallTest
+  /** Test cropping only Y direction, with no scaling. */
+  public void testCropY() {
+    testCropAndScale(0 /* cropX= */, 8 /* cropY= */, /* cropWidth= */ 16, /* cropHeight= */ 8,
+        /* scaleWidth= */ 16, /* scaleHeight= */ 8);
+  }
+
+  @Test
+  @SmallTest
+  /** Test center crop, with no scaling. */
+  public void testCenterCrop() {
+    testCropAndScale(4 /* cropX= */, 4 /* cropY= */, /* cropWidth= */ 8, /* cropHeight= */ 8,
+        /* scaleWidth= */ 8, /* scaleHeight= */ 8);
+  }
+
+  @Test
+  @SmallTest
+  /** Test non-center crop for right bottom corner, with no scaling. */
+  public void testRightBottomCornerCrop() {
+    testCropAndScale(8 /* cropX= */, 8 /* cropY= */, /* cropWidth= */ 8, /* cropHeight= */ 8,
+        /* scaleWidth= */ 8, /* scaleHeight= */ 8);
+  }
+
+  @Test
+  @SmallTest
+  /** Test combined cropping and scaling. */
+  public void testCropAndScale() {
+    testCropAndScale(4 /* cropX= */, 4 /* cropY= */, /* cropWidth= */ 12, /* cropHeight= */ 12,
+        /* scaleWidth= */ 8, /* scaleHeight= */ 8);
+  }
+}

sdk/android/native_unittests/org/webrtc/JavaVideoSourceTestHelper.java

@@ -24,12 +24,9 @@ public class JavaVideoSourceTestHelper {
   }
 
   @CalledByNative
-  public static void deliverFrame(VideoCapturer.CapturerObserver observer) {
-    final int FRAME_WIDTH = 2;
-    final int FRAME_HEIGHT = 3;
-    final int FRAME_ROTATION = 180;
-
-    observer.onFrameCaptured(new VideoFrame(
-        JavaI420Buffer.allocate(FRAME_WIDTH, FRAME_HEIGHT), FRAME_ROTATION, 0 /* timestampNs */));
+  public static void deliverFrame(
+      int width, int height, int rotation, VideoCapturer.CapturerObserver observer) {
+    observer.onFrameCaptured(
+        new VideoFrame(JavaI420Buffer.allocate(width, height), rotation, 0 /* timestampNs= */));
   }
 }

sdk/android/native_unittests/video/videosource_unittest.cc

@@ -65,15 +65,19 @@ TEST(JavaVideoSourceTest, OnFrameCapturedFrameIsDeliveredToSink) {
   jni::Java_JavaVideoSourceTestHelper_startCapture(
       env, video_track_source->GetJavaVideoCapturerObserver(env),
       true /* success */);
+  const int width = 20;
+  const int height = 32;
+  const int rotation = 180;
   jni::Java_JavaVideoSourceTestHelper_deliverFrame(
-      env, video_track_source->GetJavaVideoCapturerObserver(env));
+      env, width, height, rotation,
+      video_track_source->GetJavaVideoCapturerObserver(env));
 
   std::vector<VideoFrame> frames = test_video_sink.GetFrames();
   ASSERT_EQ(1u, frames.size());
   webrtc::VideoFrame frame = frames[0];
-  EXPECT_EQ(2, frame.width());
-  EXPECT_EQ(3, frame.height());
-  EXPECT_EQ(180, frame.rotation());
+  EXPECT_EQ(width, frame.width());
+  EXPECT_EQ(height, frame.height());
+  EXPECT_EQ(rotation, frame.rotation());
 }
 
 TEST(JavaVideoSourceTest, CapturerStartedSuccessStateBecomesLive) {