Android: Generalize and make TextureBufferImpl public

This CL generalizes TextureBufferImpl so it's useful from other contexts than
from a SurfaceTextureHelper, and fixes a bug in cropAndScale(). It also exposes
the class in the api so that clients don't have to duplicate the logic.

Bug: None
Change-Id: Ib82aa8bee025ec14de74a7be9d91fd4e5298a248
Reviewed-on: https://webrtc-review.googlesource.com/69819
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22875}

sdk/android/BUILD.gn

@@ -766,11 +766,11 @@ rtc_android_library("video_api_java") {
     "api/org/webrtc/JavaI420Buffer.java",
     "api/org/webrtc/RendererCommon.java",
     "api/org/webrtc/SurfaceTextureHelper.java",
+    "api/org/webrtc/TextureBufferImpl.java",
     "api/org/webrtc/YuvConverter.java",
     "api/org/webrtc/YuvHelper.java",
     "src/java/org/webrtc/EglBase10.java",
     "src/java/org/webrtc/EglBase14.java",
-    "src/java/org/webrtc/TextureBufferImpl.java",
   ]
 
   deps = [

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

@@ -320,12 +320,7 @@ public class SurfaceTextureHelper {
    * buffer calls returnTextureFrame() when it is released.
    */
   public TextureBuffer createTextureBuffer(int width, int height, Matrix transformMatrix) {
-    return new TextureBufferImpl(
-        width, height, TextureBuffer.Type.OES, oesTextureId, transformMatrix, this, new Runnable() {
-          @Override
-          public void run() {
-            returnTextureFrame();
-          }
-        });
+    return new TextureBufferImpl(width, height, TextureBuffer.Type.OES, oesTextureId,
+        transformMatrix, handler, yuvConverter, this ::returnTextureFrame);
   }
 }

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

@@ -11,31 +11,32 @@
 package org.webrtc;
 
 import android.graphics.Matrix;
-import java.nio.ByteBuffer;
-import java.util.concurrent.atomic.AtomicInteger;
 import javax.annotation.Nullable;
+import android.os.Handler;
 
 /**
- * Android texture buffer backed by a SurfaceTextureHelper's texture. The buffer calls
- * |releaseCallback| when it is released.
+ * Android texture buffer that glues together the necessary information together with a generic
+ * release callback. ToI420() is implemented by providing a Handler and a YuvConverter.
  */
-class TextureBufferImpl implements VideoFrame.TextureBuffer {
+public class TextureBufferImpl implements VideoFrame.TextureBuffer {
   private final int width;
   private final int height;
   private final Type type;
   private final int id;
   private final Matrix transformMatrix;
-  private final SurfaceTextureHelper surfaceTextureHelper;
+  private final Handler toI420Handler;
+  private final YuvConverter yuvConverter;
   private final RefCountDelegate refCountDelegate;
 
   public TextureBufferImpl(int width, int height, Type type, int id, Matrix transformMatrix,
-      SurfaceTextureHelper surfaceTextureHelper, @Nullable Runnable releaseCallback) {
+      Handler toI420Handler, YuvConverter yuvConverter, @Nullable Runnable releaseCallback) {
     this.width = width;
     this.height = height;
     this.type = type;
     this.id = id;
     this.transformMatrix = transformMatrix;
-    this.surfaceTextureHelper = surfaceTextureHelper;
+    this.toI420Handler = toI420Handler;
+    this.yuvConverter = yuvConverter;
     this.refCountDelegate = new RefCountDelegate(releaseCallback);
   }
 
@@ -66,7 +67,8 @@ class TextureBufferImpl implements VideoFrame.TextureBuffer {
 
   @Override
   public VideoFrame.I420Buffer toI420() {
-    return surfaceTextureHelper.textureToYuv(this);
+    return ThreadUtils.invokeAtFrontUninterruptibly(
+        toI420Handler, () -> yuvConverter.convert(this));
   }
 
   @Override
@@ -82,17 +84,12 @@ class TextureBufferImpl implements VideoFrame.TextureBuffer {
   @Override
   public VideoFrame.Buffer cropAndScale(
       int cropX, int cropY, int cropWidth, int cropHeight, int scaleWidth, int scaleHeight) {
-    retain();
-    Matrix newMatrix = new Matrix(transformMatrix);
-    newMatrix.postScale(cropWidth / (float) width, cropHeight / (float) height);
-    newMatrix.postTranslate(cropX / (float) width, cropY / (float) height);
+    final Matrix newMatrix = new Matrix(transformMatrix);
+    newMatrix.preTranslate(cropX / (float) width, cropY / (float) height);
+    newMatrix.preScale(cropWidth / (float) width, cropHeight / (float) height);
 
+    retain();
     return new TextureBufferImpl(
-        scaleWidth, scaleHeight, type, id, newMatrix, surfaceTextureHelper, new Runnable() {
-          @Override
-          public void run() {
-            release();
-          }
-        });
+        scaleWidth, scaleHeight, type, id, newMatrix, toI420Handler, yuvConverter, this ::release);
   }
 }

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

@@ -171,10 +171,10 @@ public class VideoRenderer {
             yuvStrides[1], yuvPlanes[2], yuvStrides[2],
             () -> { VideoRenderer.renderFrameDone(this); });
       } else {
-        // Note: surfaceTextureHelper being null means calling toI420 will crash.
+        // Note: No Handler or YuvConverter means calling toI420 will crash.
         buffer = new TextureBufferImpl(width, height, VideoFrame.TextureBuffer.Type.OES, textureId,
-            RendererCommon.convertMatrixToAndroidGraphicsMatrix(samplingMatrix),
-            null /* surfaceTextureHelper */, () -> { VideoRenderer.renderFrameDone(this); });
+            RendererCommon.convertMatrixToAndroidGraphicsMatrix(samplingMatrix), null /* handler */,
+            null /* yuvConverter */, () -> VideoRenderer.renderFrameDone(this));
       }
       return new VideoFrame(buffer, rotationDegree, 0 /* timestampNs */);
     }

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

@@ -18,8 +18,8 @@ import org.webrtc.VideoFrame.I420Buffer;
 import org.webrtc.VideoFrame.TextureBuffer;
 
 /**
- * Class for converting OES textures to a YUV ByteBuffer. It should be constructed on a thread with
- * an active EGL context, and only be used from that thread.
+ * Class for converting OES textures to a YUV ByteBuffer. It can be constructed on any thread, but
+ * should only be operated from a single thread with an active EGL context.
  */
 public class YuvConverter {
   // Vertex coordinates in Normalized Device Coordinates, i.e.
@@ -111,7 +111,7 @@ public class YuvConverter {
   // clang-format on
 
   private final ThreadUtils.ThreadChecker threadChecker = new ThreadUtils.ThreadChecker();
-  private final GlTextureFrameBuffer textureFrameBuffer;
+  private final GlTextureFrameBuffer textureFrameBuffer = new GlTextureFrameBuffer(GLES20.GL_RGBA);
   private TextureBuffer.Type shaderTextureType;
   private GlShader shader;
   private int texMatrixLoc;
@@ -123,8 +123,7 @@ public class YuvConverter {
    * This class should be constructed on a thread that has an active EGL context.
    */
   public YuvConverter() {
-    threadChecker.checkIsOnValidThread();
-    textureFrameBuffer = new GlTextureFrameBuffer(GLES20.GL_RGBA);
+    threadChecker.detachThread();
   }
 
   /** Converts the texture buffer to I420. */