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      1 /*
      2  * libjingle
      3  * Copyright 2012 Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 // The CaptureManager class manages VideoCapturers to make it possible to share
     29 // the same VideoCapturers across multiple instances. E.g. if two instances of
     30 // some class want to listen to same VideoCapturer they can't individually stop
     31 // and start capturing as doing so will affect the other instance.
     32 // The class employs reference counting on starting and stopping of capturing of
     33 // frames such that if anyone is still listening it will not be stopped. The
     34 // class also provides APIs for attaching VideoRenderers to a specific capturer
     35 // such that the VideoRenderers are fed frames directly from the capturer.
     36 // CaptureManager is Thread-unsafe. This means that none of its APIs may be
     37 // called concurrently. Note that callbacks are called by the VideoCapturer's
     38 // thread which is normally a separate unmarshalled thread and thus normally
     39 // require lock protection.
     40 
     41 #ifndef TALK_MEDIA_BASE_CAPTUREMANAGER_H_
     42 #define TALK_MEDIA_BASE_CAPTUREMANAGER_H_
     43 
     44 #include <map>
     45 #include <vector>
     46 
     47 #include "talk/media/base/capturerenderadapter.h"
     48 #include "talk/media/base/videocommon.h"
     49 #include "webrtc/base/sigslotrepeater.h"
     50 #include "webrtc/base/thread_checker.h"
     51 
     52 namespace cricket {
     53 
     54 class VideoCapturer;
     55 class VideoRenderer;
     56 class VideoCapturerState;
     57 
     58 class CaptureManager : public sigslot::has_slots<> {
     59  public:
     60   enum RestartOptions {
     61     kRequestRestart,
     62     kForceRestart
     63   };
     64 
     65   CaptureManager();
     66   virtual ~CaptureManager();
     67 
     68   virtual bool StartVideoCapture(VideoCapturer* video_capturer,
     69                                  const VideoFormat& desired_format);
     70   virtual bool StopVideoCapture(VideoCapturer* video_capturer,
     71                                 const VideoFormat& format);
     72 
     73   // Possibly restarts the capturer. If |options| is set to kRequestRestart,
     74   // the CaptureManager chooses whether this request can be handled with the
     75   // current state or if a restart is actually needed. If |options| is set to
     76   // kForceRestart, the capturer is restarted.
     77   virtual bool RestartVideoCapture(VideoCapturer* video_capturer,
     78                                    const VideoFormat& previous_format,
     79                                    const VideoFormat& desired_format,
     80                                    RestartOptions options);
     81 
     82   virtual bool AddVideoRenderer(VideoCapturer* video_capturer,
     83                                 VideoRenderer* video_renderer);
     84   virtual bool RemoveVideoRenderer(VideoCapturer* video_capturer,
     85                                    VideoRenderer* video_renderer);
     86 
     87   sigslot::repeater2<VideoCapturer*, CaptureState> SignalCapturerStateChange;
     88 
     89  private:
     90   typedef std::map<VideoCapturer*, VideoCapturerState*> CaptureStates;
     91 
     92   bool IsCapturerRegistered(VideoCapturer* video_capturer) const;
     93   bool RegisterVideoCapturer(VideoCapturer* video_capturer);
     94   void UnregisterVideoCapturer(VideoCapturerState* capture_state);
     95 
     96   bool StartWithBestCaptureFormat(VideoCapturerState* capture_info,
     97                                   VideoCapturer* video_capturer);
     98 
     99   VideoCapturerState* GetCaptureState(VideoCapturer* video_capturer) const;
    100   CaptureRenderAdapter* GetAdapter(VideoCapturer* video_capturer) const;
    101 
    102   rtc::ThreadChecker thread_checker_;
    103   CaptureStates capture_states_;
    104 };
    105 
    106 }  // namespace cricket
    107 
    108 #endif  // TALK_MEDIA_BASE_CAPTUREMANAGER_H_
    109