media/cast/sender/audio_sender.h

// Copyright 2014 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.

#ifndef MEDIA_CAST_SENDER_AUDIO_SENDER_H_
#define MEDIA_CAST_SENDER_AUDIO_SENDER_H_

#include <memory>

#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/time/tick_clock.h"
#include "base/time/time.h"
#include "media/base/audio_bus.h"
#include "media/cast/cast_config.h"
#include "media/cast/cast_sender.h"
#include "media/cast/sender/frame_sender.h"

namespace media {
namespace cast {

class AudioEncoder;

// Not thread safe. Only called from the main cast thread.
// This class owns all objects related to sending audio, objects that create RTP
// packets, congestion control, audio encoder, parsing and sending of
// RTCP packets.
// Additionally it posts a bunch of delayed tasks to the main thread for various
// timeouts.
class AudioSender : public FrameSender {
 public:
  AudioSender(scoped_refptr<CastEnvironment> cast_environment,
              const FrameSenderConfig& audio_config,
              const StatusChangeCallback& status_change_cb,
              CastTransport* const transport_sender);

  ~AudioSender() final;

  // Note: It is not guaranteed that |audio_frame| will actually be encoded and
  // sent, if AudioSender detects too many frames in flight.  Therefore, clients
  // should be careful about the rate at which this method is called.
  void InsertAudio(std::unique_ptr<AudioBus> audio_bus,
                   const base::TimeTicks& recorded_time);

  base::WeakPtr<AudioSender> AsWeakPtr();

 protected:
  int GetNumberOfFramesInEncoder() const final;
  base::TimeDelta GetInFlightMediaDuration() const final;

 private:
  // Called by the |audio_encoder_| with the next EncodedFrame to send.
  void OnEncodedAudioFrame(int encoder_bitrate,
                           std::unique_ptr<SenderEncodedFrame> encoded_frame,
                           int samples_skipped);

  // Encodes AudioBuses into EncodedFrames.
  std::unique_ptr<AudioEncoder> audio_encoder_;

  // The number of audio samples enqueued in |audio_encoder_|.
  int samples_in_encoder_;

  // NOTE: Weak pointers must be invalidated before all other member variables.
  base::WeakPtrFactory<AudioSender> weak_factory_;

  DISALLOW_COPY_AND_ASSIGN(AudioSender);
};

}  // namespace cast
}  // namespace media

#endif  // MEDIA_CAST_SENDER_AUDIO_SENDER_H_