Cast:Transport: Dividing A/V Initialization pipeline

media/cast/transport/cast_transport_sender.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This is the main interface for the cast transport sender. The cast sender
 // handles the cast pipeline from encoded frames (both audio and video), to
 // encryption, packetization and transport.
-// All configurations are done at creation.
 
 // Construction of the Cast Sender and the Cast Transport Sender should be done
 // in the following order:
 // 1. Create CastTransportSender.
 // 2. Create CastSender (accepts CastTransportSender as an input).
 // 3. Call CastTransportSender::SetPacketReceiver to ensure that the packets
 //    received by the CastTransportSender will be sent to the CastSender.
+// 4. Initialize audio and/or video.
+// Steps 3 & 4 can be done interchangeably.
 
 // Destruction: The CastTransportSender is assumed to be valid as long as the
 // CastSender is alive. Therefore the CastSender should be destructed before the
 // CastTransportSender.
 // This also works when the CastSender acts as a receiver for the RTCP packets
 // due to the weak pointers in the ReceivedPacket method in cast_sender_impl.cc.
 
 #ifndef MEDIA_CAST_TRANSPORT_CAST_TRANSPORT_SENDER_H_
 #define MEDIA_CAST_TRANSPORT_CAST_TRANSPORT_SENDER_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time/tick_clock.h"
 #include "media/cast/transport/cast_transport_config.h"
 #include "media/cast/transport/cast_transport_defines.h"
 
 namespace net {
 class NetLog;
 }  // namespace net
 
 namespace media {
 namespace cast {
 namespace transport {
 
+// Following the initialization of either audio or video an initialization
+// status will be sent via this callback.
 typedef base::Callback<void(CastTransportStatus status)>
     CastTransportStatusCallback;
 
 typedef base::Callback<void(const RtcpSenderInfo& sender_info,
                             base::TimeTicks time_sent,
                             uint32 rtp_timestamp)> CastTransportRtpStatistics;
 
 // The application should only trigger this class from the transport thread.
 class CastTransportSender : public base::NonThreadSafe {
  public:
-  static CastTransportSender* CreateCastTransportSender(
+  static scoped_ptr<CastTransportSender> Create(
       net::NetLog* net_log,
       base::TickClock* clock,
-      const CastTransportConfig& config,
+      const net::IPEndPoint& local_end_point,
+      const net::IPEndPoint& remote_end_point,
       const CastTransportStatusCallback& status_callback,
       const scoped_refptr<base::SingleThreadTaskRunner>& transport_task_runner);
 
   virtual ~CastTransportSender() {}
 
+  // Audio/Video initialization.
+  // Encoded frames cannot be transmitted until the relevant initialize method
+  // is called.
+  virtual void InitializeAudio(const CastTransportAudioConfig& config) = 0;
+
+  virtual void InitializeVideo(const CastTransportVideoConfig& config) = 0;
+
   // Sets the Cast packet receiver. Should be called after creation on the
   // Cast sender. Packets won't be received until this function is called.
   virtual void SetPacketReceiver(
       const PacketReceiverCallback& packet_receiver) = 0;
 
   // The following two functions handle the encoded media frames (audio and
   // video) to be processed.
   // Frames will be encrypted, packetized and transmitted to the network.
   virtual void InsertCodedAudioFrame(const EncodedAudioFrame* audio_frame,
                                      const base::TimeTicks& recorded_time) = 0;
 
   virtual void InsertCodedVideoFrame(const EncodedVideoFrame* video_frame,
                                      const base::TimeTicks& capture_time) = 0;
 
   // Builds an RTCP packet and sends it to the network.
   virtual void SendRtcpFromRtpSender(uint32 packet_type_flags,
                                      const RtcpSenderInfo& sender_info,
                                      const RtcpDlrrReportBlock& dlrr,
                                      const RtcpSenderLogMessage& sender_log,
                                      uint32 sending_ssrc,
                                      const std::string& c_name) = 0;
 
   // Retransmission request.
   virtual void ResendPackets(
       bool is_audio,
       const MissingFramesAndPacketsMap& missing_packets) = 0;
 
-  // Audio/Video RTP statistics.
   // RTP statistics will be returned on a regular interval on the designated
   // callback.
+  // Must be called after initialization of the corresponding A/V pipeline.
   virtual void SubscribeAudioRtpStatsCallback(
       const CastTransportRtpStatistics& callback) = 0;
 
   virtual void SubscribeVideoRtpStatsCallback(
       const CastTransportRtpStatistics& callback) = 0;
 };
 
 }  // namespace transport
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_TRANSPORT_CAST_TRANSPORT_SENDER_H_