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