// Copyright (c) 2012 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_AUDIO_AUDIO_MANAGER_H_
#define MEDIA_AUDIO_AUDIO_MANAGER_H_
#include <string>
#include "base/basictypes.h"
#include "base/memory/ref_counted.h"
#include "base/strings/string16.h"
#include "media/audio/audio_device_name.h"
#include "media/audio/audio_logging.h"
#include "media/audio/audio_parameters.h"
namespace base {
class SingleThreadTaskRunner;
}
namespace media {
class AudioInputStream;
class AudioOutputStream;
// Manages all audio resources. Provides some convenience functions that avoid
// the need to provide iterators over the existing streams.
class MEDIA_EXPORT AudioManager {
public:
virtual ~AudioManager();
// Construct the audio manager; only one instance is allowed. The manager
// will forward CreateAudioLog() calls to the provided AudioLogFactory; as
// such |audio_log_factory| must outlive the AudioManager.
static AudioManager* Create(AudioLogFactory* audio_log_factory);
// Similar to Create() except uses a FakeAudioLogFactory for testing.
static AudioManager* CreateForTesting();
// Returns the pointer to the last created instance, or NULL if not yet
// created. This is a utility method for the code outside of media directory,
// like src/chrome.
static AudioManager* Get();
// Returns true if the OS reports existence of audio devices. This does not
// guarantee that the existing devices support all formats and sample rates.
virtual bool HasAudioOutputDevices() = 0;
// Returns true if the OS reports existence of audio recording devices. This
// does not guarantee that the existing devices support all formats and
// sample rates.
virtual bool HasAudioInputDevices() = 0;
// Returns a human readable string for the model/make of the active audio
// input device for this computer.
virtual base::string16 GetAudioInputDeviceModel() = 0;
// Opens the platform default audio input settings UI.
// Note: This could invoke an external application/preferences pane, so
// ideally must not be called from the UI thread or other time sensitive
// threads to avoid blocking the rest of the application.
virtual void ShowAudioInputSettings() = 0;
// Appends a list of available input devices to |device_names|,
// which must initially be empty. It is not guaranteed that all the
// devices in the list support all formats and sample rates for
// recording.
//
// Not threadsafe; in production this should only be called from the
// Audio IO thread (see GetTaskRunner()).
virtual void GetAudioInputDeviceNames(AudioDeviceNames* device_names) = 0;
// Appends a list of available output devices to |device_names|,
// which must initially be empty.
//
// Not threadsafe; in production this should only be called from the
// Audio IO thread (see GetTaskRunner()).
virtual void GetAudioOutputDeviceNames(AudioDeviceNames* device_names) = 0;
// Factory for all the supported stream formats. |params| defines parameters
// of the audio stream to be created.
//
// |params.sample_per_packet| is the requested buffer allocation which the
// audio source thinks it can usually fill without blocking. Internally two
// or three buffers are created, one will be locked for playback and one will
// be ready to be filled in the call to AudioSourceCallback::OnMoreData().
//
// To create a stream for the default output device, pass an empty string
// for |device_id|, otherwise the specified audio device will be opened.
//
// Returns NULL if the combination of the parameters is not supported, or if
// we have reached some other platform specific limit.
//
// |params.format| can be set to AUDIO_PCM_LOW_LATENCY and that has two
// effects:
// 1- Instead of triple buffered the audio will be double buffered.
// 2- A low latency driver or alternative audio subsystem will be used when
// available.
//
// Do not free the returned AudioOutputStream. It is owned by AudioManager.
virtual AudioOutputStream* MakeAudioOutputStream(
const AudioParameters& params,
const std::string& device_id) = 0;
// Creates new audio output proxy. A proxy implements
// AudioOutputStream interface, but unlike regular output stream
// created with MakeAudioOutputStream() it opens device only when a
// sound is actually playing.
virtual AudioOutputStream* MakeAudioOutputStreamProxy(
const AudioParameters& params,
const std::string& device_id) = 0;
// Factory to create audio recording streams.
// |channels| can be 1 or 2.
// |sample_rate| is in hertz and can be any value supported by the platform.
// |bits_per_sample| can be any value supported by the platform.
// |samples_per_packet| is in hertz as well and can be 0 to |sample_rate|,
// with 0 suggesting that the implementation use a default value for that
// platform.
// Returns NULL if the combination of the parameters is not supported, or if
// we have reached some other platform specific limit.
//
// Do not free the returned AudioInputStream. It is owned by AudioManager.
// When you are done with it, call |Stop()| and |Close()| to release it.
virtual AudioInputStream* MakeAudioInputStream(
const AudioParameters& params, const std::string& device_id) = 0;
// Returns the task runner used for audio IO.
virtual scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() = 0;
// Heavyweight tasks should use GetWorkerTaskRunner() instead of
// GetTaskRunner(). On most platforms they are the same, but some share the
// UI loop with the audio IO loop.
virtual scoped_refptr<base::SingleThreadTaskRunner> GetWorkerTaskRunner() = 0;
// Allows clients to listen for device state changes; e.g. preferred sample
// rate or channel layout changes. The typical response to receiving this
// callback is to recreate the stream.
class AudioDeviceListener {
public:
virtual void OnDeviceChange() = 0;
};
virtual void AddOutputDeviceChangeListener(AudioDeviceListener* listener) = 0;
virtual void RemoveOutputDeviceChangeListener(
AudioDeviceListener* listener) = 0;
// Returns the default output hardware audio parameters for opening output
// streams. It is a convenience interface to
// AudioManagerBase::GetPreferredOutputStreamParameters and each AudioManager
// does not need their own implementation to this interface.
// TODO(tommi): Remove this method and use GetOutputStreamParameteres instead.
virtual AudioParameters GetDefaultOutputStreamParameters() = 0;
// Returns the output hardware audio parameters for a specific output device.
virtual AudioParameters GetOutputStreamParameters(
const std::string& device_id) = 0;
// Returns the input hardware audio parameters of the specific device
// for opening input streams. Each AudioManager needs to implement their own
// version of this interface.
virtual AudioParameters GetInputStreamParameters(
const std::string& device_id) = 0;
// Returns the device id of an output device that belongs to the same hardware
// as the specified input device.
// If the hardware has only an input device (e.g. a webcam), the return value
// will be empty (which the caller can then interpret to be the default output
// device). Implementations that don't yet support this feature, must return
// an empty string.
virtual std::string GetAssociatedOutputDeviceID(
const std::string& input_device_id) = 0;
// Create a new AudioLog object for tracking the behavior for one or more
// instances of the given component. See AudioLogFactory for more details.
virtual scoped_ptr<AudioLog> CreateAudioLog(
AudioLogFactory::AudioComponent component) = 0;
// Called when a component has detected a OS level audio wedge. Shuts down
// all active audio streams and then restarts them transparently. See
// http://crbug.com/160920
virtual void FixWedgedAudio() = 0;
protected:
AudioManager();
private:
DISALLOW_COPY_AND_ASSIGN(AudioManager);
};
} // namespace media
#endif // MEDIA_AUDIO_AUDIO_MANAGER_H_