content/renderer/media_recorder/audio_track_encoder.h

// Copyright 2017 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 CONTENT_RENDERER_MEDIA_RECORDER_AUDIO_TRACK_ENCODER_H_
#define CONTENT_RENDERER_MEDIA_RECORDER_AUDIO_TRACK_ENCODER_H_

#include <memory>

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/threading/thread.h"
#include "base/threading/thread_checker.h"
#include "base/time/time.h"
#include "media/base/audio_bus.h"
#include "media/base/audio_parameters.h"

namespace content {

// Base interface for an AudioTrackEncoder. This class and its subclasses are
// used by AudioTrackRecorder to encode audio before output. These are private
// classes and should not be used outside of AudioTrackRecorder.
//
// AudioTrackEncoder is created and destroyed on ATR's main thread (usually the
// main render thread) but otherwise should operate entirely on
// |encoder_thread_|, which is owned by AudioTrackRecorder. Be sure to delete
// |encoder_thread_| before deleting the AudioTrackEncoder using it.
class AudioTrackEncoder : public base::RefCountedThreadSafe<AudioTrackEncoder> {
 public:
  using OnEncodedAudioCB =
      base::Callback<void(const media::AudioParameters& params,
                          std::unique_ptr<std::string> encoded_data,
                          base::TimeTicks capture_time)>;

  explicit AudioTrackEncoder(OnEncodedAudioCB on_encoded_audio_cb);

  virtual void OnSetFormat(const media::AudioParameters& params) = 0;
  virtual void EncodeAudio(std::unique_ptr<media::AudioBus> audio_bus,
                           base::TimeTicks capture_time) = 0;

  void set_paused(bool paused) { paused_ = paused; }

 protected:
  friend class base::RefCountedThreadSafe<AudioTrackEncoder>;

  virtual ~AudioTrackEncoder();

  bool paused_;

  const OnEncodedAudioCB on_encoded_audio_cb_;

  THREAD_CHECKER(encoder_thread_checker_);

  // The original input audio parameters.
  media::AudioParameters input_params_;

  DISALLOW_COPY_AND_ASSIGN(AudioTrackEncoder);
};

}  // namespace content

#endif  // CONTENT_RENDERER_MEDIA_RECORDER_AUDIO_TRACK_ENCODER_H_