Expose functionality to convert TextureBuffer to I420.

Bug: webrtc:8392
Change-Id: I79682efbef3aecbba904aa5047b229833fae25e8
Reviewed-on: https://webrtc-review.googlesource.com/8940
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20313}

sdk/android/BUILD.gn

@@ -436,6 +436,7 @@ android_library("libjingle_peerconnection_java") {
     "api/org/webrtc/VideoSink.java",
     "api/org/webrtc/VideoSource.java",
     "api/org/webrtc/VideoTrack.java",
+    "api/org/webrtc/YuvConverter.java",
     "src/java/org/webrtc/AndroidVideoTrackSourceObserver.java",
     "src/java/org/webrtc/BaseBitrateAdjuster.java",
     "src/java/org/webrtc/BitrateAdjuster.java",
@@ -461,7 +462,6 @@ android_library("libjingle_peerconnection_java") {
     "src/java/org/webrtc/VideoDecoderWrapperCallback.java",
     "src/java/org/webrtc/VideoEncoderWrapperCallback.java",
     "src/java/org/webrtc/WrappedNativeI420Buffer.java",
-    "src/java/org/webrtc/YuvConverter.java",
   ]
 
   deps = [

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

@@ -231,8 +231,11 @@ public class SurfaceTextureHelper {
     });
   }
 
-  public void textureToYUV(final ByteBuffer buf, final int width, final int height,
-      final int stride, final int textureId, final float[] transformMatrix) {
+  /** Deprecated, use textureToYuv. */
+  @Deprecated
+  @SuppressWarnings("deprecation") // yuvConverter.convert is deprecated
+  void textureToYUV(final ByteBuffer buf, final int width, final int height, final int stride,
+      final int textureId, final float[] transformMatrix) {
     if (textureId != oesTextureId) {
       throw new IllegalStateException("textureToByteBuffer called with unexpected textureId");
     }
@@ -248,6 +251,25 @@ public class SurfaceTextureHelper {
     });
   }
 
+  /**
+   * Posts to the correct thread to convert |textureBuffer| to I420. Must only be called with
+   * textures generated by this SurfaceTextureHelper.
+   */
+  public VideoFrame.I420Buffer textureToYuv(final TextureBuffer textureBuffer) {
+    if (textureBuffer.getTextureId() != oesTextureId) {
+      throw new IllegalStateException("textureToByteBuffer called with unexpected textureId");
+    }
+
+    final VideoFrame.I420Buffer[] result = new VideoFrame.I420Buffer[1];
+    ThreadUtils.invokeAtFrontUninterruptibly(handler, () -> {
+      if (yuvConverter == null) {
+        yuvConverter = new YuvConverter();
+      }
+      result[0] = yuvConverter.convert(textureBuffer);
+    });
+    return result[0];
+  }
+
   private void updateTexImage() {
     // SurfaceTexture.updateTexImage apparently can compete and deadlock with eglSwapBuffers,
     // as observed on Nexus 5. Therefore, synchronize it with the EGL functions.

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

@@ -15,8 +15,8 @@ import android.os.HandlerThread;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.nio.ByteBuffer;
-import java.util.concurrent.CountDownLatch;
 import java.util.ArrayList;
+import java.util.concurrent.CountDownLatch;
 
 /**
  * Can be used to save the video frames to file.
@@ -94,7 +94,7 @@ public class VideoFileRenderer implements VideoRenderer.Callbacks {
     final float[] texMatrix = RendererCommon.multiplyMatrices(rotatedSamplingMatrix, layoutMatrix);
 
     try {
-      ByteBuffer buffer = nativeCreateNativeByteBuffer(outputFrameSize);
+      ByteBuffer buffer = JniCommon.allocateNativeByteBuffer(outputFrameSize);
       if (!frame.yuvFrame) {
         yuvConverter.convert(outputFrameBuffer, outputFileWidth, outputFileHeight, outputFileWidth,
             frame.textureId, texMatrix);
@@ -153,7 +153,7 @@ public class VideoFileRenderer implements VideoRenderer.Callbacks {
 
         videoOutFile.write(data);
 
-        nativeFreeNativeByteBuffer(buffer);
+        JniCommon.freeNativeByteBuffer(buffer);
       }
       videoOutFile.close();
       Logging.d(TAG, "Video written to disk as " + outputFileName + ". Number frames are "
@@ -167,8 +167,4 @@ public class VideoFileRenderer implements VideoRenderer.Callbacks {
   public static native void nativeI420Scale(ByteBuffer srcY, int strideY, ByteBuffer srcU,
       int strideU, ByteBuffer srcV, int strideV, int width, int height, ByteBuffer dst,
       int dstWidth, int dstHeight);
-
-  public static native ByteBuffer nativeCreateNativeByteBuffer(int size);
-
-  public static native void nativeFreeNativeByteBuffer(ByteBuffer buffer);
 }

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

@@ -11,6 +11,8 @@
 package org.webrtc;
 
 import android.graphics.Matrix;
+import android.opengl.GLES11Ext;
+import android.opengl.GLES20;
 import java.nio.ByteBuffer;
 
 /**
@@ -88,7 +90,20 @@ public class VideoFrame {
    * Interface for buffers that are stored as a single texture, either in OES or RGB format.
    */
   public interface TextureBuffer extends Buffer {
-    enum Type { OES, RGB }
+    enum Type {
+      OES(GLES11Ext.GL_TEXTURE_EXTERNAL_OES),
+      RGB(GLES20.GL_TEXTURE_2D);
+
+      private final int glTarget;
+
+      private Type(final int glTarget) {
+        this.glTarget = glTarget;
+      }
+
+      public int getGlTarget() {
+        return glTarget;
+      }
+    }
 
     Type getType();
     int getTextureId();

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

@@ -14,6 +14,8 @@ import android.opengl.GLES11Ext;
 import android.opengl.GLES20;
 import java.nio.ByteBuffer;
 import java.nio.FloatBuffer;
+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
@@ -50,12 +52,12 @@ class YuvConverter {
       + "    interp_tc = (texMatrix * in_tc).xy;\n"
       + "}\n";
 
-  private static final String FRAGMENT_SHADER =
+  private static final String OES_FRAGMENT_SHADER =
         "#extension GL_OES_EGL_image_external : require\n"
       + "precision mediump float;\n"
       + "varying vec2 interp_tc;\n"
       + "\n"
-      + "uniform samplerExternalOES oesTex;\n"
+      + "uniform samplerExternalOES tex;\n"
       // Difference in texture coordinate corresponding to one
       // sub-pixel in the x direction.
       + "uniform vec2 xUnit;\n"
@@ -70,22 +72,51 @@ class YuvConverter {
       // try to do it as a vec3 x mat3x4, followed by an add in of a
       // constant vector.
       + "  gl_FragColor.r = coeffs.a + dot(coeffs.rgb,\n"
-      + "      texture2D(oesTex, interp_tc - 1.5 * xUnit).rgb);\n"
+      + "      texture2D(tex, interp_tc - 1.5 * xUnit).rgb);\n"
       + "  gl_FragColor.g = coeffs.a + dot(coeffs.rgb,\n"
-      + "      texture2D(oesTex, interp_tc - 0.5 * xUnit).rgb);\n"
+      + "      texture2D(tex, interp_tc - 0.5 * xUnit).rgb);\n"
       + "  gl_FragColor.b = coeffs.a + dot(coeffs.rgb,\n"
-      + "      texture2D(oesTex, interp_tc + 0.5 * xUnit).rgb);\n"
+      + "      texture2D(tex, interp_tc + 0.5 * xUnit).rgb);\n"
       + "  gl_FragColor.a = coeffs.a + dot(coeffs.rgb,\n"
-      + "      texture2D(oesTex, interp_tc + 1.5 * xUnit).rgb);\n"
+      + "      texture2D(tex, interp_tc + 1.5 * xUnit).rgb);\n"
+      + "}\n";
+
+  private static final String RGB_FRAGMENT_SHADER =
+        "precision mediump float;\n"
+      + "varying vec2 interp_tc;\n"
+      + "\n"
+      + "uniform sample2D tex;\n"
+      // Difference in texture coordinate corresponding to one
+      // sub-pixel in the x direction.
+      + "uniform vec2 xUnit;\n"
+      // Color conversion coefficients, including constant term
+      + "uniform vec4 coeffs;\n"
+      + "\n"
+      + "void main() {\n"
+      // Since the alpha read from the texture is always 1, this could
+      // be written as a mat4 x vec4 multiply. However, that seems to
+      // give a worse framerate, possibly because the additional
+      // multiplies by 1.0 consume resources. TODO(nisse): Could also
+      // try to do it as a vec3 x mat3x4, followed by an add in of a
+      // constant vector.
+      + "  gl_FragColor.r = coeffs.a + dot(coeffs.rgb,\n"
+      + "      texture2D(tex, interp_tc - 1.5 * xUnit).rgb);\n"
+      + "  gl_FragColor.g = coeffs.a + dot(coeffs.rgb,\n"
+      + "      texture2D(tex, interp_tc - 0.5 * xUnit).rgb);\n"
+      + "  gl_FragColor.b = coeffs.a + dot(coeffs.rgb,\n"
+      + "      texture2D(tex, interp_tc + 0.5 * xUnit).rgb);\n"
+      + "  gl_FragColor.a = coeffs.a + dot(coeffs.rgb,\n"
+      + "      texture2D(tex, interp_tc + 1.5 * xUnit).rgb);\n"
       + "}\n";
   // clang-format on
 
-  private final GlTextureFrameBuffer textureFrameBuffer;
-  private final GlShader shader;
-  private final int texMatrixLoc;
-  private final int xUnitLoc;
-  private final int coeffsLoc;
   private final ThreadUtils.ThreadChecker threadChecker = new ThreadUtils.ThreadChecker();
+  private final GlTextureFrameBuffer textureFrameBuffer;
+  private TextureBuffer.Type shaderTextureType;
+  private GlShader shader;
+  private int texMatrixLoc;
+  private int xUnitLoc;
+  private int coeffsLoc;
   private boolean released = false;
 
   /**
@@ -94,12 +125,80 @@ class YuvConverter {
   public YuvConverter() {
     threadChecker.checkIsOnValidThread();
     textureFrameBuffer = new GlTextureFrameBuffer(GLES20.GL_RGBA);
-    shader = new GlShader(VERTEX_SHADER, FRAGMENT_SHADER);
+  }
+
+  /** Converts the texture buffer to I420. */
+  public I420Buffer convert(TextureBuffer textureBuffer) {
+    final int width = textureBuffer.getWidth();
+    final int height = textureBuffer.getHeight();
+
+    // SurfaceTextureHelper requires a stride that is divisible by 8.  Round width up.
+    // See SurfaceTextureHelper for details on the size and format.
+    final int stride = ((width + 7) / 8) * 8;
+    final int uvHeight = (height + 1) / 2;
+    // Due to the layout used by SurfaceTextureHelper, vPos + stride * uvHeight would overrun the
+    // buffer.  Add one row at the bottom to compensate for this.  There will never be data in the
+    // extra row, but now other code does not have to deal with v stride * v height exceeding the
+    // buffer's capacity.
+    final int size = stride * (height + uvHeight + 1);
+    ByteBuffer buffer = JniCommon.allocateNativeByteBuffer(size);
+    convert(buffer, width, height, stride, textureBuffer.getTextureId(),
+        RendererCommon.convertMatrixFromAndroidGraphicsMatrix(textureBuffer.getTransformMatrix()),
+        textureBuffer.getType());
+
+    final int yPos = 0;
+    final int uPos = yPos + stride * height;
+    // Rows of U and V alternate in the buffer, so V data starts after the first row of U.
+    final int vPos = uPos + stride / 2;
+
+    buffer.position(yPos);
+    buffer.limit(yPos + stride * height);
+    ByteBuffer dataY = buffer.slice();
+
+    buffer.position(uPos);
+    buffer.limit(uPos + stride * uvHeight);
+    ByteBuffer dataU = buffer.slice();
+
+    buffer.position(vPos);
+    buffer.limit(vPos + stride * uvHeight);
+    ByteBuffer dataV = buffer.slice();
+
+    // SurfaceTextureHelper uses the same stride for Y, U, and V data.
+    return JavaI420Buffer.wrap(width, height, dataY, stride, dataU, stride, dataV, stride,
+        () -> { JniCommon.freeNativeByteBuffer(buffer); });
+  }
+
+  /** Deprecated, use convert(TextureBuffer). */
+  @Deprecated
+  void convert(ByteBuffer buf, int width, int height, int stride, int srcTextureId,
+      float[] transformMatrix) {
+    convert(buf, width, height, stride, srcTextureId, transformMatrix, TextureBuffer.Type.OES);
+  }
+
+  private void initShader(TextureBuffer.Type textureType) {
+    if (shader != null) {
+      shader.release();
+    }
+
+    final String fragmentShader;
+    switch (textureType) {
+      case OES:
+        fragmentShader = OES_FRAGMENT_SHADER;
+        break;
+      case RGB:
+        fragmentShader = RGB_FRAGMENT_SHADER;
+        break;
+      default:
+        throw new IllegalArgumentException("Unsupported texture type.");
+    }
+
+    shaderTextureType = textureType;
+    shader = new GlShader(VERTEX_SHADER, fragmentShader);
     shader.useProgram();
     texMatrixLoc = shader.getUniformLocation("texMatrix");
     xUnitLoc = shader.getUniformLocation("xUnit");
     coeffsLoc = shader.getUniformLocation("coeffs");
-    GLES20.glUniform1i(shader.getUniformLocation("oesTex"), 0);
+    GLES20.glUniform1i(shader.getUniformLocation("tex"), 0);
     GlUtil.checkNoGLES2Error("Initialize fragment shader uniform values.");
     // Initialize vertex shader attributes.
     shader.setVertexAttribArray("in_pos", 2, DEVICE_RECTANGLE);
@@ -108,12 +207,15 @@ class YuvConverter {
     shader.setVertexAttribArray("in_tc", 2, TEXTURE_RECTANGLE);
   }
 
-  public void convert(ByteBuffer buf, int width, int height, int stride, int srcTextureId,
-      float[] transformMatrix) {
+  private void convert(ByteBuffer buf, int width, int height, int stride, int srcTextureId,
+      float[] transformMatrix, TextureBuffer.Type textureType) {
     threadChecker.checkIsOnValidThread();
     if (released) {
       throw new IllegalStateException("YuvConverter.convert called on released object");
     }
+    if (textureType != shaderTextureType) {
+      initShader(textureType);
+    }
 
     // We draw into a buffer laid out like
     //
@@ -174,7 +276,7 @@ class YuvConverter {
     GlUtil.checkNoGLES2Error("glBindFramebuffer");
 
     GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
-    GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, srcTextureId);
+    GLES20.glBindTexture(textureType.getGlTarget(), srcTextureId);
     GLES20.glUniformMatrix4fv(texMatrixLoc, 1, false, transformMatrix, 0);
 
     // Draw Y
@@ -211,13 +313,15 @@ class YuvConverter {
 
     // Unbind texture. Reportedly needed on some devices to get
     // the texture updated from the camera.
-    GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 0);
+    GLES20.glBindTexture(textureType.getGlTarget(), 0);
   }
 
   public void release() {
     threadChecker.checkIsOnValidThread();
     released = true;
+    if (shader != null) {
       shader.release();
+    }
     textureFrameBuffer.release();
   }
 }

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

@@ -22,6 +22,7 @@ import android.support.test.filters.SmallTest;
 import java.nio.ByteBuffer;
 import java.util.concurrent.CountDownLatch;
 import org.chromium.base.test.BaseJUnit4ClassRunner;
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -95,6 +96,12 @@ public class SurfaceTextureHelperTest {
         + actual);
   }
 
+  @Before
+  public void setUp() {
+    // Load the JNI library for textureToYuv.
+    NativeLibrary.initialize(new NativeLibrary.DefaultLoader());
+  }
+
   /**
    * Test normal use by receiving three uniform texture frames. Texture frames are returned as early
    * as possible. The texture pixel values are inspected by drawing the texture frame to a pixel
@@ -428,7 +435,7 @@ public class SurfaceTextureHelperTest {
 
   @Test
   @MediumTest
-  public void testTexturetoYUV() throws InterruptedException {
+  public void testTexturetoYuv() throws InterruptedException {
     final int width = 16;
     final int height = 16;
 
@@ -482,21 +489,33 @@ public class SurfaceTextureHelperTest {
       //    ...
       //    368 UUUUUUUU VVVVVVVV
       //    384 buffer end
-      ByteBuffer buffer = ByteBuffer.allocateDirect(width * height * 3 / 2);
-      surfaceTextureHelper.textureToYUV(
-          buffer, width, height, width, listener.oesTextureId, listener.transformMatrix);
+      final VideoFrame.I420Buffer i420 =
+          surfaceTextureHelper.textureToYuv(surfaceTextureHelper.createTextureBuffer(width, height,
+              RendererCommon.convertMatrixToAndroidGraphicsMatrix(listener.transformMatrix)));
 
       surfaceTextureHelper.returnTextureFrame();
 
       // Allow off-by-one differences due to different rounding.
-      while (buffer.position() < width * height) {
-        assertClose(1, buffer.get() & 0xff, ref_y[i]);
+      final ByteBuffer dataY = i420.getDataY();
+      final int strideY = i420.getStrideY();
+      for (int y = 0; y < height; y++) {
+        for (int x = 0; x < width; x++) {
+          assertClose(1, ref_y[i], dataY.get(y * strideY + x) & 0xFF);
+        }
+      }
+
+      final int chromaWidth = width / 2;
+      final int chromaHeight = height / 2;
+
+      final ByteBuffer dataU = i420.getDataU();
+      final ByteBuffer dataV = i420.getDataV();
+      final int strideU = i420.getStrideU();
+      final int strideV = i420.getStrideV();
+      for (int y = 0; y < chromaHeight; y++) {
+        for (int x = 0; x < chromaWidth; x++) {
+          assertClose(1, ref_u[i], dataU.get(y * strideU + x) & 0xFF);
+          assertClose(1, ref_v[i], dataV.get(y * strideV + x) & 0xFF);
         }
-      while (buffer.hasRemaining()) {
-        if (buffer.position() % width < width / 2)
-          assertClose(1, buffer.get() & 0xff, ref_u[i]);
-        else
-          assertClose(1, buffer.get() & 0xff, ref_v[i]);
       }
     }
 

sdk/android/src/java/org/webrtc/JniCommon.java

@@ -10,9 +10,14 @@
 
 package org.webrtc;
 
+import java.nio.ByteBuffer;
+
 /** Class with static JNI helper functions that are used in many places. */
 class JniCommon {
   /** Functions to increment/decrement an rtc::RefCountInterface pointer. */
   static native void nativeAddRef(long nativeRefCountedPointer);
   static native void nativeReleaseRef(long nativeRefCountedPointer);
+
+  public static native ByteBuffer allocateNativeByteBuffer(int size);
+  public static native void freeNativeByteBuffer(ByteBuffer buffer);
 }

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

@@ -67,41 +67,7 @@ class TextureBufferImpl implements VideoFrame.TextureBuffer {
 
   @Override
   public VideoFrame.I420Buffer toI420() {
-    if (type == Type.RGB) {
-      throw new RuntimeException("toI420 for RGB frames not implemented yet");
-    }
-    // SurfaceTextureHelper requires a stride that is divisible by 8.  Round width up.
-    // See SurfaceTextureHelper for details on the size and format.
-    int stride = ((width + 7) / 8) * 8;
-    int uvHeight = (height + 1) / 2;
-    // Due to the layout used by SurfaceTextureHelper, vPos + stride * uvHeight would overrun the
-    // buffer.  Add one row at the bottom to compensate for this.  There will never be data in the
-    // extra row, but now other code does not have to deal with v stride * v height exceeding the
-    // buffer's capacity.
-    int size = stride * (height + uvHeight + 1);
-    ByteBuffer buffer = ByteBuffer.allocateDirect(size);
-    surfaceTextureHelper.textureToYUV(buffer, width, height, stride, id,
-        RendererCommon.convertMatrixFromAndroidGraphicsMatrix(transformMatrix));
-
-    int yPos = 0;
-    int uPos = yPos + stride * height;
-    // Rows of U and V alternate in the buffer, so V data starts after the first row of U.
-    int vPos = uPos + stride / 2;
-
-    buffer.position(yPos);
-    buffer.limit(yPos + stride * height);
-    ByteBuffer dataY = buffer.slice();
-
-    buffer.position(uPos);
-    buffer.limit(uPos + stride * uvHeight);
-    ByteBuffer dataU = buffer.slice();
-
-    buffer.position(vPos);
-    buffer.limit(vPos + stride * uvHeight);
-    ByteBuffer dataV = buffer.slice();
-
-    // SurfaceTextureHelper uses the same stride for Y, U, and V data.
-    return JavaI420Buffer.wrap(width, height, dataY, stride, dataU, stride, dataV, stride, null);
+    return surfaceTextureHelper.textureToYuv(this);
   }
 
   @Override

sdk/android/src/jni/jni_common.cc

@@ -11,7 +11,8 @@
 #include "rtc_base/refcount.h"
 #include "sdk/android/src/jni/jni_helpers.h"
 
-namespace webrtc_jni {
+namespace webrtc {
+namespace jni {
 
 JNI_FUNCTION_DECLARATION(void,
                          JniCommon_nativeAddRef,
@@ -31,4 +32,24 @@ JNI_FUNCTION_DECLARATION(void,
       ->Release();
 }
 
-}  // namespace webrtc_jni
+JNI_FUNCTION_DECLARATION(jobject,
+                         JniCommon_allocateNativeByteBuffer,
+                         JNIEnv* jni,
+                         jclass,
+                         jint size) {
+  void* new_data = ::operator new(size);
+  jobject byte_buffer = jni->NewDirectByteBuffer(new_data, size);
+  return byte_buffer;
+}
+
+JNI_FUNCTION_DECLARATION(void,
+                         JniCommon_freeNativeByteBuffer,
+                         JNIEnv* jni,
+                         jclass,
+                         jobject byte_buffer) {
+  void* data = jni->GetDirectBufferAddress(byte_buffer);
+  ::operator delete(data);
+}
+
+}  // namespace jni
+}  // namespace webrtc

sdk/android/src/jni/native_handle_impl.cc

@@ -306,6 +306,8 @@ rtc::scoped_refptr<I420BufferInterface> AndroidTextureBuffer::ToI420() {
   JNIEnv* jni = AttachCurrentThreadIfNeeded();
   ScopedLocalRefFrame local_ref_frame(jni);
 
+  // TODO(sakal): This call to a deperecated method will be removed when
+  // AndroidTextureBuffer is removed.
   jmethodID transform_mid = GetMethodID(
       jni,
       GetObjectClass(jni, surface_texture_helper_),

sdk/android/src/jni/videofilerenderer_jni.cc

@@ -65,23 +65,5 @@ Java_org_webrtc_VideoFileRenderer_nativeI420Scale(JNIEnv* jni,
   }
 }
 
-extern "C" JNIEXPORT jobject JNICALL
-Java_org_webrtc_VideoFileRenderer_nativeCreateNativeByteBuffer(JNIEnv* jni,
-                                                               jclass,
-                                                               jint size) {
-  void* new_data = ::operator new(size);
-  jobject byte_buffer = jni->NewDirectByteBuffer(new_data, size);
-  return byte_buffer;
-}
-
-extern "C" JNIEXPORT void JNICALL
-Java_org_webrtc_VideoFileRenderer_nativeFreeNativeByteBuffer(
-    JNIEnv* jni,
-    jclass,
-    jobject byte_buffer) {
-  void* data = jni->GetDirectBufferAddress(byte_buffer);
-  ::operator delete(data);
-}
-
 }  // namespace jni
 }  // namespace webrtc