media/cast/sender/video_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_VIDEO_SENDER_H_
#define MEDIA_CAST_SENDER_VIDEO_SENDER_H_

#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/threading/non_thread_safe.h"
#include "base/time/tick_clock.h"
#include "base/time/time.h"
#include "media/cast/cast_config.h"
#include "media/cast/sender/congestion_control.h"
#include "media/cast/sender/frame_sender.h"

namespace media {

class VideoFrame;

namespace cast {

class CastTransportSender;
class VideoEncoder;

typedef base::Callback<void(base::TimeDelta)> PlayoutDelayChangeCB;

// Not thread safe. Only called from the main cast thread.
// This class owns all objects related to sending video, objects that create RTP
// packets, congestion control, video encoder, parsing and sending of
// RTCP packets.
// Additionally it posts a bunch of delayed tasks to the main thread for various
// timeouts.
class VideoSender : public FrameSender,
                    public base::NonThreadSafe,
                    public base::SupportsWeakPtr<VideoSender> {
 public:
  VideoSender(scoped_refptr<CastEnvironment> cast_environment,
              const VideoSenderConfig& video_config,
              const CastInitializationCallback& initialization_cb,
              const CreateVideoEncodeAcceleratorCallback& create_vea_cb,
              const CreateVideoEncodeMemoryCallback& create_video_encode_mem_cb,
              CastTransportSender* const transport_sender,
              const PlayoutDelayChangeCB& playout_delay_change_cb);

  virtual ~VideoSender();

  // Note: It is not guaranteed that |video_frame| will actually be encoded and
  // sent, if VideoSender detects too many frames in flight.  Therefore, clients
  // should be careful about the rate at which this method is called.
  //
  // Note: It is invalid to call this method if InitializationResult() returns
  // anything but STATUS_VIDEO_INITIALIZED.
  void InsertRawVideoFrame(const scoped_refptr<media::VideoFrame>& video_frame,
                           const base::TimeTicks& capture_time);

 protected:
  virtual int GetNumberOfFramesInEncoder() const OVERRIDE;
  virtual base::TimeDelta GetInFlightMediaDuration() const OVERRIDE;
  virtual void OnAck(uint32 frame_id) OVERRIDE;

 private:
  // Called when the encoder is initialized or has failed to initialize.
  void OnEncoderInitialized(
      const CastInitializationCallback& initialization_cb,
      CastInitializationStatus status);

  // Called by the |video_encoder_| with the next EncodedFrame to send.
  void OnEncodedVideoFrame(int encoder_bitrate,
                           scoped_ptr<EncodedFrame> encoded_frame);

  // Encodes media::VideoFrame images into EncodedFrames.  Per configuration,
  // this will point to either the internal software-based encoder or a proxy to
  // a hardware-based encoder.
  scoped_ptr<VideoEncoder> video_encoder_;

  // The number of frames queued for encoding, but not yet sent.
  int frames_in_encoder_;

  // The duration of video queued for encoding, but not yet sent.
  base::TimeDelta duration_in_encoder_;

  // The timestamp of the frame that was last enqueued in |video_encoder_|.
  base::TimeTicks last_enqueued_frame_reference_time_;

  // Remember what we set the bitrate to before, no need to set it again if
  // we get the same value.
  uint32 last_bitrate_;

  PlayoutDelayChangeCB playout_delay_change_cb_;

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

  DISALLOW_COPY_AND_ASSIGN(VideoSender);
};

}  // namespace cast
}  // namespace media

#endif  // MEDIA_CAST_SENDER_VIDEO_SENDER_H_