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      1 // Copyright 2013 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 CHROME_RENDERER_MEDIA_CAST_RTP_STREAM_H_
      6 #define CHROME_RENDERER_MEDIA_CAST_RTP_STREAM_H_
      7 
      8 #include <string>
      9 #include <vector>
     10 
     11 #include "base/basictypes.h"
     12 #include "base/memory/ref_counted.h"
     13 #include "base/memory/scoped_ptr.h"
     14 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
     15 
     16 class CastAudioSink;
     17 class CastSession;
     18 class CastVideoSink;
     19 
     20 // A key value pair structure for codec specific parameters.
     21 struct CastCodecSpecificParams {
     22   std::string key;
     23   std::string value;
     24 
     25   CastCodecSpecificParams();
     26   ~CastCodecSpecificParams();
     27 };
     28 
     29 // Defines the basic properties of a payload supported by cast transport.
     30 struct CastRtpPayloadParams {
     31   // RTP specific field that identifies the content type.
     32   int payload_type;
     33 
     34   // RTP specific field to identify a stream.
     35   int ssrc;
     36 
     37   // Update frequency of payload sample.
     38   int clock_rate;
     39 
     40   // Maximum bitrate.
     41   int max_bitrate;
     42 
     43   // Minimum bitrate.
     44   int min_bitrate;
     45 
     46   // Number of audio channels.
     47   int channels;
     48 
     49   // Width and height of the video content.
     50   int width;
     51   int height;
     52 
     53   // Name of the codec used.
     54   std::string codec_name;
     55 
     56   // List of codec specific parameters.
     57   std::vector<CastCodecSpecificParams> codec_specific_params;
     58 
     59   CastRtpPayloadParams();
     60   ~CastRtpPayloadParams();
     61 };
     62 
     63 // Defines the capabilities of the transport.
     64 struct CastRtpCaps {
     65   // Defines a list of supported payloads.
     66   std::vector<CastRtpPayloadParams> payloads;
     67 
     68   // Names of supported RTCP features.
     69   std::vector<std::string> rtcp_features;
     70 
     71   // Names of supported FEC (Forward Error Correction) mechanisms.
     72   std::vector<std::string> fec_mechanisms;
     73 
     74   CastRtpCaps();
     75   ~CastRtpCaps();
     76 };
     77 
     78 typedef CastRtpCaps CastRtpParams;
     79 
     80 // This object represents a RTP stream that encodes and optionally
     81 // encrypt audio or video data from a WebMediaStreamTrack.
     82 // Note that this object does not actually output packets. It allows
     83 // configuration of encoding and RTP parameters and control such a logical
     84 // stream.
     85 class CastRtpStream {
     86  public:
     87   CastRtpStream(const blink::WebMediaStreamTrack& track,
     88                 const scoped_refptr<CastSession>& session);
     89   ~CastRtpStream();
     90 
     91   // Return capabilities currently supported by this transport.
     92   CastRtpCaps GetCaps();
     93 
     94   // Return parameters set to this transport.
     95   CastRtpParams GetParams();
     96 
     97   // Begin encoding of media stream and then submit the encoded streams
     98   // to underlying transport.
     99   void Start(const CastRtpParams& params);
    100 
    101   // Stop encoding.
    102   void Stop();
    103 
    104  private:
    105   // Return true if this track is an audio track. Return false if this
    106   // track is a video track.
    107   bool IsAudio() const;
    108 
    109   blink::WebMediaStreamTrack track_;
    110   const scoped_refptr<CastSession> cast_session_;
    111   scoped_ptr<CastAudioSink> audio_sink_;
    112   scoped_ptr<CastVideoSink> video_sink_;
    113   CastRtpParams params_;
    114 
    115   DISALLOW_COPY_AND_ASSIGN(CastRtpStream);
    116 };
    117 
    118 #endif  // CHROME_RENDERER_MEDIA_CAST_RTP_STREAM_H_
    119