AVFoundationVideoCapturer: Fix apply_rotation() logic

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 113 matching lines @@
       !CMSampleBufferIsValid(sample_buffer) ||
       !CMSampleBufferDataIsReady(sample_buffer)) {
     return;
   }
 
   CVImageBufferRef image_buffer = CMSampleBufferGetImageBuffer(sample_buffer);
   if (image_buffer == NULL) {
     return;
   }
 
-  const int captured_width = CVPixelBufferGetWidth(image_buffer);
-  const int captured_height = CVPixelBufferGetHeight(image_buffer);
+  int captured_width = CVPixelBufferGetWidth(image_buffer);
+  int captured_height = CVPixelBufferGetHeight(image_buffer);
 
   int adapted_width;
   int adapted_height;
   int crop_width;
   int crop_height;
   int crop_x;
   int crop_y;
   int64_t translated_camera_time_us;
 
   if (!AdaptFrame(captured_width, captured_height,
                   rtc::TimeNanos() / rtc::kNumNanosecsPerMicrosec,
                   rtc::TimeMicros(), &adapted_width, &adapted_height,
                   &crop_width, &crop_height, &crop_x, &crop_y,
                   &translated_camera_time_us)) {
     return;
   }
 
   rtc::scoped_refptr<VideoFrameBuffer> buffer =
       new rtc::RefCountedObject<CoreVideoFrameBuffer>(
           image_buffer,
           adapted_width, adapted_height,
           crop_width, crop_height,
           crop_x, crop_y);
 
   // Applying rotation is only supported for legacy reasons and performance is
   // not critical here.
   if (apply_rotation() && rotation != kVideoRotation_0) {
     buffer = buffer->NativeToI420Buffer();
-    rtc::scoped_refptr<I420Buffer> rotated_buffer =
-        (rotation == kVideoRotation_180)
-            ? I420Buffer::Create(adapted_width, adapted_height)
-            : I420Buffer::Create(adapted_height, adapted_width);
+    rtc::scoped_refptr<I420Buffer> rotated_buffer;
+    if (rotation == kVideoRotation_0 || rotation == kVideoRotation_180) {

[kthelgason, 2017/01/09 08:18:28]

The first case can never happen due to the outer conditional

[magjed_webrtc, 2017/01/09 09:31:14]

Right, and the previous code just did (rotation == kVideoRotation_180), but I
think it's slightly clearer and more future proof to include the
kVideoRotation_0 case.

+      rotated_buffer = I420Buffer::Create(adapted_width, adapted_height);
+    } else {
+      // Swap width and height.
+      rotated_buffer = I420Buffer::Create(adapted_height, adapted_width);
+      std::swap(captured_width, captured_height);
+    }
     libyuv::I420Rotate(
         buffer->DataY(), buffer->StrideY(),
         buffer->DataU(), buffer->StrideU(),
         buffer->DataV(), buffer->StrideV(),
         rotated_buffer->MutableDataY(), rotated_buffer->StrideY(),
         rotated_buffer->MutableDataU(), rotated_buffer->StrideU(),
         rotated_buffer->MutableDataV(), rotated_buffer->StrideV(),
         buffer->width(), buffer->height(),
         static_cast<libyuv::RotationMode>(rotation));
     buffer = rotated_buffer;
+    rotation = kVideoRotation_0;
   }
 
   OnFrame(webrtc::VideoFrame(buffer, rotation, translated_camera_time_us),
           captured_width, captured_height);
 }
 
 }  // namespace webrtc