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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:
     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 
     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:
     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:
    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.
    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:
    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.
    159   virtual cricket::AudioRenderer* GetRenderer() { return NULL; }
    160 
    161  protected:
    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:
    188   virtual ~MediaStreamInterface() {}
    189 };
    190 
    191 }  // namespace webrtc
    192 
    193 #endif  // TALK_APP_WEBRTC_MEDIASTREAMINTERFACE_H_
    194