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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 // This file contains interfaces for MediaStream, MediaTrack and MediaSource.
29 // These interfaces are used for implementing MediaStream and MediaTrack as
30 // defined in http://dev.w3.org/2011/webrtc/editor/webrtc.html#stream-api. These
31 // interfaces must be used only with PeerConnection. PeerConnectionManager
32 // interface provides the factory methods to create MediaStream and MediaTracks.
33 
34 #ifndef TALK_APP_WEBRTC_MEDIASTREAMINTERFACE_H_
35 #define TALK_APP_WEBRTC_MEDIASTREAMINTERFACE_H_
36 
37 #include <string>
38 #include <vector>
39 
40 #include "talk/base/basictypes.h"
41 #include "talk/base/refcount.h"
42 #include "talk/base/scoped_ref_ptr.h"
43 
44 namespace cricket {
45 
46 class AudioRenderer;
47 class VideoCapturer;
48 class VideoRenderer;
49 class VideoFrame;
50 
51 }  // namespace cricket
52 
53 namespace webrtc {
54 
55 // Generic observer interface.
56 class ObserverInterface {
57  public:
58   virtual void OnChanged() = 0;
59 
60  protected:
~ObserverInterface()61   virtual ~ObserverInterface() {}
62 };
63 
64 class NotifierInterface {
65  public:
66   virtual void RegisterObserver(ObserverInterface* observer) = 0;
67   virtual void UnregisterObserver(ObserverInterface* observer) = 0;
68 
~NotifierInterface()69   virtual ~NotifierInterface() {}
70 };
71 
72 // Base class for sources. A MediaStreamTrack have an underlying source that
73 // provide media. A source can be shared with multiple tracks.
74 // TODO(perkj): Implement sources for local and remote audio tracks and
75 // remote video tracks.
76 class MediaSourceInterface : public talk_base::RefCountInterface,
77                              public NotifierInterface {
78  public:
79   enum SourceState {
80     kInitializing,
81     kLive,
82     kEnded,
83     kMuted
84   };
85 
86   virtual SourceState state() const = 0;
87 
88  protected:
~MediaSourceInterface()89   virtual ~MediaSourceInterface() {}
90 };
91 
92 // Information about a track.
93 class MediaStreamTrackInterface : public talk_base::RefCountInterface,
94                                   public NotifierInterface {
95  public:
96   enum TrackState {
97     kInitializing,  // Track is beeing negotiated.
98     kLive = 1,  // Track alive
99     kEnded = 2,  // Track have ended
100     kFailed = 3,  // Track negotiation failed.
101   };
102 
103   virtual std::string kind() const = 0;
104   virtual std::string id() const = 0;
105   virtual bool enabled() const = 0;
106   virtual TrackState state() const = 0;
107   virtual bool set_enabled(bool enable) = 0;
108   // These methods should be called by implementation only.
109   virtual bool set_state(TrackState new_state) = 0;
110 
111  protected:
~MediaStreamTrackInterface()112   virtual ~MediaStreamTrackInterface() {}
113 };
114 
115 // Interface for rendering VideoFrames from a VideoTrack
116 class VideoRendererInterface {
117  public:
118   virtual void SetSize(int width, int height) = 0;
119   virtual void RenderFrame(const cricket::VideoFrame* frame) = 0;
120 
121  protected:
122   // The destructor is protected to prevent deletion via the interface.
123   // This is so that we allow reference counted classes, where the destructor
124   // should never be public, to implement the interface.
~VideoRendererInterface()125   virtual ~VideoRendererInterface() {}
126 };
127 
128 class VideoSourceInterface;
129 
130 class VideoTrackInterface : public MediaStreamTrackInterface {
131  public:
132   // Register a renderer that will render all frames received on this track.
133   virtual void AddRenderer(VideoRendererInterface* renderer) = 0;
134   // Deregister a renderer.
135   virtual void RemoveRenderer(VideoRendererInterface* renderer) = 0;
136 
137   virtual VideoSourceInterface* GetSource() const = 0;
138 
139  protected:
~VideoTrackInterface()140   virtual ~VideoTrackInterface() {}
141 };
142 
143 // AudioSourceInterface is a reference counted source used for AudioTracks.
144 // The same source can be used in multiple AudioTracks.
145 // TODO(perkj): Extend this class with necessary methods to allow separate
146 // sources for each audio track.
147 class AudioSourceInterface : public MediaSourceInterface {
148 };
149 
150 class AudioTrackInterface : public MediaStreamTrackInterface {
151  public:
152   // TODO(xians): Figure out if the following interface should be const or not.
153   virtual AudioSourceInterface* GetSource() const =  0;
154 
155   // Gets a pointer to the audio renderer of this AudioTrack.
156   // The pointer is valid for the lifetime of this AudioTrack.
157   // TODO(xians): Make the following interface pure virtual once Chrome has its
158   // implementation.
GetRenderer()159   virtual cricket::AudioRenderer* GetRenderer() { return NULL; }
160 
161  protected:
~AudioTrackInterface()162   virtual ~AudioTrackInterface() {}
163 };
164 
165 typedef std::vector<talk_base::scoped_refptr<AudioTrackInterface> >
166     AudioTrackVector;
167 typedef std::vector<talk_base::scoped_refptr<VideoTrackInterface> >
168     VideoTrackVector;
169 
170 class MediaStreamInterface : public talk_base::RefCountInterface,
171                              public NotifierInterface {
172  public:
173   virtual std::string label() const = 0;
174 
175   virtual AudioTrackVector GetAudioTracks() = 0;
176   virtual VideoTrackVector GetVideoTracks() = 0;
177   virtual talk_base::scoped_refptr<AudioTrackInterface>
178       FindAudioTrack(const std::string& track_id) = 0;
179   virtual talk_base::scoped_refptr<VideoTrackInterface>
180       FindVideoTrack(const std::string& track_id) = 0;
181 
182   virtual bool AddTrack(AudioTrackInterface* track) = 0;
183   virtual bool AddTrack(VideoTrackInterface* track) = 0;
184   virtual bool RemoveTrack(AudioTrackInterface* track) = 0;
185   virtual bool RemoveTrack(VideoTrackInterface* track) = 0;
186 
187  protected:
~MediaStreamInterface()188   virtual ~MediaStreamInterface() {}
189 };
190 
191 }  // namespace webrtc
192 
193 #endif  // TALK_APP_WEBRTC_MEDIASTREAMINTERFACE_H_
194