Use I420Buffer rather than VideoFrameBuffer when writing pixels.

webrtc/sdk/objc/Framework/Classes/avfoundationvideocapturer.mm

 /*
  *  Copyright 2015 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.
  */
 
@@ skipping 722 matching lines @@
     // TODO(magjed): Avoid converting to I420.
     rtc::scoped_refptr<webrtc::I420Buffer> scaled_buffer(
         _buffer_pool.CreateBuffer(adapted_width, adapted_height));
     scaled_buffer->CropAndScaleFrom(buffer->NativeToI420Buffer(), crop_x,
                                     crop_y, crop_width, crop_height);
     if (!apply_rotation() || rotation == webrtc::kVideoRotation_0) {
       buffer = scaled_buffer;
     } else {
       // Applying rotation is only supported for legacy reasons and performance
       // is not critical here.
-      buffer = (rotation == webrtc::kVideoRotation_180)
-          ? I420Buffer::Create(adapted_width, adapted_height)
-          : I420Buffer::Create(adapted_height, adapted_width);
-      libyuv::I420Rotate(scaled_buffer->DataY(), scaled_buffer->StrideY(),
-                         scaled_buffer->DataU(), scaled_buffer->StrideU(),
-                         scaled_buffer->DataV(), scaled_buffer->StrideV(),
-                         buffer->MutableDataY(), buffer->StrideY(),
-                         buffer->MutableDataU(), buffer->StrideU(),
-                         buffer->MutableDataV(), buffer->StrideV(),
-                         crop_width, crop_height,
-                         static_cast<libyuv::RotationMode>(rotation));
+      rtc::scoped_refptr<webrtc::I420Buffer> rotated_buffer(
+          (rotation == webrtc::kVideoRotation_180)
+              ? I420Buffer::Create(adapted_width, adapted_height)
+              : I420Buffer::Create(adapted_height, adapted_width));
+      libyuv::I420Rotate(
+          scaled_buffer->DataY(), scaled_buffer->StrideY(),
+          scaled_buffer->DataU(), scaled_buffer->StrideU(),
+          scaled_buffer->DataV(), scaled_buffer->StrideV(),
+          rotated_buffer->MutableDataY(), rotated_buffer->StrideY(),
+          rotated_buffer->MutableDataU(), rotated_buffer->StrideU(),
+          rotated_buffer->MutableDataV(), rotated_buffer->StrideV(),
+          crop_width, crop_height,
+          static_cast<libyuv::RotationMode>(rotation));
+      buffer = rotated_buffer;
     }
   }
 
   OnFrame(cricket::WebRtcVideoFrame(buffer, rotation,
                                     translated_camera_time_us, 0),
           captured_width, captured_height);
 }
 
 }  // namespace webrtc