Rotate frames correctly for back camera

media/capture/video/video_capture_device_client.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/capture/video/video_capture_device_client.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 62 matching lines @@
 };
 
 VideoCaptureDeviceClient::VideoCaptureDeviceClient(
     std::unique_ptr<VideoFrameReceiver> receiver,
     const scoped_refptr<VideoCaptureBufferPool>& buffer_pool,
     const VideoCaptureJpegDecoderFactoryCB& jpeg_decoder_factory)
     : receiver_(std::move(receiver)),
       jpeg_decoder_factory_callback_(jpeg_decoder_factory),
       external_jpeg_decoder_initialized_(false),
       buffer_pool_(buffer_pool),
+      is_back_camera_(false),
       last_captured_pixel_format_(media::PIXEL_FORMAT_UNKNOWN) {}
 
 VideoCaptureDeviceClient::~VideoCaptureDeviceClient() {
   // This should be on the platform auxiliary thread since
   // |external_jpeg_decoder_| need to be destructed on the same thread as
   // OnIncomingCapturedData.
 }
 
 void VideoCaptureDeviceClient::OnIncomingCapturedData(
     const uint8_t* data,
@@ skipping 33 matching lines @@
   const int new_unrotated_width = frame_format.frame_size.width() & ~1;
   const int new_unrotated_height = frame_format.frame_size.height() & ~1;
 
   int destination_width = new_unrotated_width;
   int destination_height = new_unrotated_height;
   if (rotation == 90 || rotation == 270)
     std::swap(destination_width, destination_height);
 
   DCHECK_EQ(0, rotation % 90) << " Rotation must be a multiple of 90, now: "
                               << rotation;
+
+  if (is_back_camera_) {
+    // For back camera, we need to rotate (360 - screen_rotation).
+    // Ex: when screen rotation is 90, we have to rotate the frame by 270
+    // clockwise.
+    rotation = (360 - rotation) % 360;

[wuchengli, 2016/11/16 12:15:19]

Can we calculate the right rotation in VideoCaptureDeviceLinux and pass it to
VideoCaptureDeviceClient::OnIncomingCapturedData?

[shenghao, 2016/11/17 08:41:45]

Done.

+  }
+
   libyuv::RotationMode rotation_mode = libyuv::kRotate0;
   if (rotation == 90)
     rotation_mode = libyuv::kRotate90;
   else if (rotation == 180)
     rotation_mode = libyuv::kRotate180;
   else if (rotation == 270)
     rotation_mode = libyuv::kRotate270;
 
   const gfx::Size dimensions(destination_width, destination_height);
   uint8_t *y_plane_data, *u_plane_data, *v_plane_data;
@@ skipping 202 matching lines @@
 }
 
 void VideoCaptureDeviceClient::OnLog(const std::string& message) {
   receiver_->OnLog(message);
 }
 
 double VideoCaptureDeviceClient::GetBufferPoolUtilization() const {
   return buffer_pool_->GetBufferPoolUtilization();
 }
 
+void VideoCaptureDeviceClient::SetCameraFacing(bool is_back_camera) {
+  is_back_camera_ = is_back_camera;
+}
+
 std::unique_ptr<media::VideoCaptureDevice::Client::Buffer>
 VideoCaptureDeviceClient::ReserveI420OutputBuffer(
     const gfx::Size& dimensions,
     media::VideoPixelStorage storage,
     uint8_t** y_plane_data,
     uint8_t** u_plane_data,
     uint8_t** v_plane_data) {
   DCHECK(storage == media::PIXEL_STORAGE_CPU);
   DCHECK(dimensions.height());
   DCHECK(dimensions.width());
@@ skipping 37 matching lines @@
     return;
   memcpy(buffer->data(), data, length);
   const VideoCaptureFormat output_format =
       VideoCaptureFormat(frame_format.frame_size, frame_format.frame_rate,
                          media::PIXEL_FORMAT_Y16, media::PIXEL_STORAGE_CPU);
   OnIncomingCapturedBuffer(std::move(buffer), output_format, reference_time,
                            timestamp);
 }
 
 }  // namespace media