remoting/host/cast_video_capturer_adapter.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef REMOTING_HOST_CAST_VIDEO_CAPTURER_ADAPTER_H_
   6 #define REMOTING_HOST_CAST_VIDEO_CAPTURER_ADAPTER_H_
   7
   8 #include <vector>
   9
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/threading/thread_checker.h"
  12 #include "base/timer/timer.h"
  13 #include "third_party/libjingle/source/talk/media/base/videocapturer.h"
  14 #include "third_party/webrtc/modules/desktop_capture/screen_capturer.h"
  15
  16 namespace base {
  17 class SingleThreadTaskRunner;
  18 }  // namespace base
  19
  20 namespace webrtc {
  21 class DesktopFrame;
  22 }  // namespace webrtc
  23
  24 namespace remoting {
  25
  26 // This class controls the capture of video frames from the desktop and is used
  27 // to construct a VideoSource as part of the webrtc PeerConnection API.
  28 // CastVideoCapturerAdapter acts as an adapter between webrtc::DesktopCapturer
  29 // and the cricket::VideoCapturer interface, which it implements. It is used
  30 // to construct a cricket::VideoSource for a PeerConnection, to capture frames
  31 // of the desktop. As indicated in the base implementation, Start() and Stop()
  32 // should be called on the same thread.
  33 class CastVideoCapturerAdapter : public cricket::VideoCapturer,
  34                                  public webrtc::DesktopCapturer::Callback {
  35  public:
  36   explicit CastVideoCapturerAdapter(
  37       scoped_ptr<webrtc::DesktopCapturer> capturer);
  38
  39   ~CastVideoCapturerAdapter() override;
  40
  41   // webrtc::DesktopCapturer::Callback implementation.
  42   webrtc::SharedMemory* CreateSharedMemory(size_t size) override;
  43   // Converts |frame| to a cricket::CapturedFrame and emits that via
  44   // SignalFrameCaptured for the base::VideoCapturer implementation to process.
  45   void OnCaptureCompleted(webrtc::DesktopFrame* frame) override;
  46
  47   // cricket::VideoCapturer implementation.
  48   bool GetBestCaptureFormat(const cricket::VideoFormat& desired,
  49                             cricket::VideoFormat* best_format) override;
  50   cricket::CaptureState Start(
  51       const cricket::VideoFormat& capture_format) override;
  52   bool Pause(bool pause) override;
  53   void Stop() override;
  54   bool IsRunning() override;
  55   bool IsScreencast() const override;
  56   bool GetPreferredFourccs(std::vector<uint32>* fourccs) override;
  57
  58  private:
  59   // Kicks off the next frame capture using |desktop_capturer_|.
  60   // The captured frame will be passed to OnCaptureCompleted().
  61   void CaptureNextFrame();
  62
  63   // |thread_checker_| is bound to the peer connection worker thread.
  64   base::ThreadChecker thread_checker_;
  65
  66   // Used to capture frames.
  67   scoped_ptr<webrtc::DesktopCapturer> desktop_capturer_;
  68
  69   // Used to schedule periodic screen captures.
  70   scoped_ptr<base::RepeatingTimer<CastVideoCapturerAdapter> > capture_timer_;
  71
  72   // Used to set the elapsed_time attribute of captured frames.
  73   base::TimeTicks start_time_;
  74
  75   DISALLOW_COPY_AND_ASSIGN(CastVideoCapturerAdapter);
  76 };
  77
  78 }  // namespace remoting
  79
  80 #endif  // REMOTING_HOST_CAST_VIDEO_CAPTURER_ADAPTER_H_
  81