audio_input_device.h | Explore in Territory

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Low-latency audio capturing class utilizing audio input stream provided
// by a server process by use of an IPC interface.
//
// Relationship of classes:
//
//  AudioInputController                 AudioInputDevice
//           ^                                  ^
//           |                                  |
//           v                  IPC             v
// MojoAudioInputStream    <----------->  AudioInputIPC
//           ^                            (MojoAudioInputIPC)
//           |
//           v
// AudioInputDeviceManager
//
// Transportation of audio samples from the browser to the render process
// is done by using shared memory in combination with a SyncSocket.
// The AudioInputDevice user registers an AudioInputDevice::CaptureCallback by
// calling Initialize().  The callback will be called with recorded audio from
// the underlying audio layers.
// The session ID is used by the RenderFrameAudioInputStreamFactory to start
// the device referenced by this ID.
//
// State sequences:
//
// Start -> CreateStream ->
//       <- OnStreamCreated <-
//       -> RecordStream ->
//
// AudioInputDevice::Capture => low latency audio transport on audio thread =>
//
// Stop ->  CloseStream -> Close
//
// This class depends on the audio transport thread. That thread is responsible
// for calling the CaptureCallback and feeding it audio samples from the server
// side audio layer using a socket and shared memory.
//
// Implementation notes:
// - The user must call Stop() before deleting the class instance.

#ifndef MEDIA_AUDIO_AUDIO_INPUT_DEVICE_H_
#define MEDIA_AUDIO_AUDIO_INPUT_DEVICE_H_

#include <memory>
#include <optional>
#include <string>

#include "base/compiler_specific.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/read_only_shared_memory_region.h"
#include "base/sequence_checker.h"
#include "base/threading/platform_thread.h"
#include "media/audio/alive_checker.h"
#include "media/audio/audio_device_thread.h"
#include "media/audio/audio_input_ipc.h"
#include "media/base/audio_capturer_source.h"
#include "media/base/audio_parameters.h"
#include "media/base/media_export.h"

namespace media {

class MEDIA_EXPORT AudioInputDevice : public AudioCapturerSource,
                                      public AudioInputIPCDelegate { … };

}  // namespace media

#endif  // MEDIA_AUDIO_AUDIO_INPUT_DEVICE_H_
chromium/media/audio/audio_input_device.h
