// 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.
#include "media/audio/mac/audio_manager_mac.h"
#include <CoreAudio/AudioHardware.h>
#include <string>
#include "base/bind.h"
#include "base/command_line.h"
#include "base/mac/mac_logging.h"
#include "base/mac/scoped_cftyperef.h"
#include "base/power_monitor/power_monitor.h"
#include "base/power_monitor/power_observer.h"
#include "base/strings/sys_string_conversions.h"
#include "base/threading/thread_checker.h"
#include "media/audio/audio_parameters.h"
#include "media/audio/mac/audio_auhal_mac.h"
#include "media/audio/mac/audio_input_mac.h"
#include "media/audio/mac/audio_low_latency_input_mac.h"
#include "media/base/bind_to_current_loop.h"
#include "media/base/channel_layout.h"
#include "media/base/limits.h"
#include "media/base/media_switches.h"
namespace media {
// Maximum number of output streams that can be open simultaneously.
static const int kMaxOutputStreams = 50;
// Define bounds for for low-latency input and output streams.
static const int kMinimumInputOutputBufferSize = 128;
static const int kMaximumInputOutputBufferSize = 4096;
// Default sample-rate on most Apple hardware.
static const int kFallbackSampleRate = 44100;
static bool HasAudioHardware(AudioObjectPropertySelector selector) {
AudioDeviceID output_device_id = kAudioObjectUnknown;
const AudioObjectPropertyAddress property_address = {
selector,
kAudioObjectPropertyScopeGlobal, // mScope
kAudioObjectPropertyElementMaster // mElement
};
UInt32 output_device_id_size = static_cast<UInt32>(sizeof(output_device_id));
OSStatus err = AudioObjectGetPropertyData(kAudioObjectSystemObject,
&property_address,
0, // inQualifierDataSize
NULL, // inQualifierData
&output_device_id_size,
&output_device_id);
return err == kAudioHardwareNoError &&
output_device_id != kAudioObjectUnknown;
}
// Retrieves information on audio devices, and prepends the default
// device to the list if the list is non-empty.
static void GetAudioDeviceInfo(bool is_input,
media::AudioDeviceNames* device_names) {
// Query the number of total devices.
AudioObjectPropertyAddress property_address = {
kAudioHardwarePropertyDevices,
kAudioObjectPropertyScopeGlobal,
kAudioObjectPropertyElementMaster
};
UInt32 size = 0;
OSStatus result = AudioObjectGetPropertyDataSize(kAudioObjectSystemObject,
&property_address,
0,
NULL,
&size);
if (result || !size)
return;
int device_count = size / sizeof(AudioDeviceID);
// Get the array of device ids for all the devices, which includes both
// input devices and output devices.
scoped_ptr<AudioDeviceID, base::FreeDeleter>
devices(static_cast<AudioDeviceID*>(malloc(size)));
AudioDeviceID* device_ids = devices.get();
result = AudioObjectGetPropertyData(kAudioObjectSystemObject,
&property_address,
0,
NULL,
&size,
device_ids);
if (result)
return;
// Iterate over all available devices to gather information.
for (int i = 0; i < device_count; ++i) {
// Get the number of input or output channels of the device.
property_address.mScope = is_input ?
kAudioDevicePropertyScopeInput : kAudioDevicePropertyScopeOutput;
property_address.mSelector = kAudioDevicePropertyStreams;
size = 0;
result = AudioObjectGetPropertyDataSize(device_ids[i],
&property_address,
0,
NULL,
&size);
if (result || !size)
continue;
// Get device UID.
CFStringRef uid = NULL;
size = sizeof(uid);
property_address.mSelector = kAudioDevicePropertyDeviceUID;
property_address.mScope = kAudioObjectPropertyScopeGlobal;
result = AudioObjectGetPropertyData(device_ids[i],
&property_address,
0,
NULL,
&size,
&uid);
if (result)
continue;
// Get device name.
CFStringRef name = NULL;
property_address.mSelector = kAudioObjectPropertyName;
property_address.mScope = kAudioObjectPropertyScopeGlobal;
result = AudioObjectGetPropertyData(device_ids[i],
&property_address,
0,
NULL,
&size,
&name);
if (result) {
if (uid)
CFRelease(uid);
continue;
}
// Store the device name and UID.
media::AudioDeviceName device_name;
device_name.device_name = base::SysCFStringRefToUTF8(name);
device_name.unique_id = base::SysCFStringRefToUTF8(uid);
device_names->push_back(device_name);
// We are responsible for releasing the returned CFObject. See the
// comment in the AudioHardware.h for constant
// kAudioDevicePropertyDeviceUID.
if (uid)
CFRelease(uid);
if (name)
CFRelease(name);
}
if (!device_names->empty()) {
// Prepend the default device to the list since we always want it to be
// on the top of the list for all platforms. There is no duplicate
// counting here since the default device has been abstracted out before.
media::AudioDeviceName name;
name.device_name = AudioManagerBase::kDefaultDeviceName;
name.unique_id = AudioManagerBase::kDefaultDeviceId;
device_names->push_front(name);
}
}
static AudioDeviceID GetAudioDeviceIdByUId(bool is_input,
const std::string& device_id) {
AudioObjectPropertyAddress property_address = {
kAudioHardwarePropertyDevices,
kAudioObjectPropertyScopeGlobal,
kAudioObjectPropertyElementMaster
};
AudioDeviceID audio_device_id = kAudioObjectUnknown;
UInt32 device_size = sizeof(audio_device_id);
OSStatus result = -1;
if (device_id == AudioManagerBase::kDefaultDeviceId || device_id.empty()) {
// Default Device.
property_address.mSelector = is_input ?
kAudioHardwarePropertyDefaultInputDevice :
kAudioHardwarePropertyDefaultOutputDevice;
result = AudioObjectGetPropertyData(kAudioObjectSystemObject,
&property_address,
0,
0,
&device_size,
&audio_device_id);
} else {
// Non-default device.
base::ScopedCFTypeRef<CFStringRef> uid(
base::SysUTF8ToCFStringRef(device_id));
AudioValueTranslation value;
value.mInputData = &uid;
value.mInputDataSize = sizeof(CFStringRef);
value.mOutputData = &audio_device_id;
value.mOutputDataSize = device_size;
UInt32 translation_size = sizeof(AudioValueTranslation);
property_address.mSelector = kAudioHardwarePropertyDeviceForUID;
result = AudioObjectGetPropertyData(kAudioObjectSystemObject,
&property_address,
0,
0,
&translation_size,
&value);
}
if (result) {
OSSTATUS_DLOG(WARNING, result) << "Unable to query device " << device_id
<< " for AudioDeviceID";
}
return audio_device_id;
}
template <class T>
void StopStreams(std::list<T*>* streams) {
for (typename std::list<T*>::iterator it = streams->begin();
it != streams->end();
++it) {
// Stop() is safe to call multiple times, so it doesn't matter if a stream
// has already been stopped.
(*it)->Stop();
}
streams->clear();
}
class AudioManagerMac::AudioPowerObserver : public base::PowerObserver {
public:
AudioPowerObserver()
: is_suspending_(false),
is_monitoring_(base::PowerMonitor::Get()) {
// The PowerMonitor requires signifcant setup (a CFRunLoop and preallocated
// IO ports) so it's not available under unit tests. See the OSX impl of
// base::PowerMonitorDeviceSource for more details.
if (!is_monitoring_)
return;
base::PowerMonitor::Get()->AddObserver(this);
}
virtual ~AudioPowerObserver() {
DCHECK(thread_checker_.CalledOnValidThread());
if (!is_monitoring_)
return;
base::PowerMonitor::Get()->RemoveObserver(this);
}
bool ShouldDeferStreamStart() {
DCHECK(thread_checker_.CalledOnValidThread());
// Start() should be deferred if the system is in the middle of a suspend or
// has recently started the process of resuming.
return is_suspending_ || base::TimeTicks::Now() < earliest_start_time_;
}
private:
virtual void OnSuspend() OVERRIDE {
DCHECK(thread_checker_.CalledOnValidThread());
is_suspending_ = true;
}
virtual void OnResume() OVERRIDE {
DCHECK(thread_checker_.CalledOnValidThread());
is_suspending_ = false;
earliest_start_time_ = base::TimeTicks::Now() +
base::TimeDelta::FromSeconds(kStartDelayInSecsForPowerEvents);
}
bool is_suspending_;
const bool is_monitoring_;
base::TimeTicks earliest_start_time_;
base::ThreadChecker thread_checker_;
DISALLOW_COPY_AND_ASSIGN(AudioPowerObserver);
};
AudioManagerMac::AudioManagerMac(AudioLogFactory* audio_log_factory)
: AudioManagerBase(audio_log_factory),
current_sample_rate_(0),
current_output_device_(kAudioDeviceUnknown) {
SetMaxOutputStreamsAllowed(kMaxOutputStreams);
// Task must be posted last to avoid races from handing out "this" to the
// audio thread. Always PostTask even if we're on the right thread since
// AudioManager creation is on the startup path and this may be slow.
GetTaskRunner()->PostTask(FROM_HERE, base::Bind(
&AudioManagerMac::InitializeOnAudioThread, base::Unretained(this)));
}
AudioManagerMac::~AudioManagerMac() {
if (GetTaskRunner()->BelongsToCurrentThread()) {
ShutdownOnAudioThread();
} else {
// It's safe to post a task here since Shutdown() will wait for all tasks to
// complete before returning.
GetTaskRunner()->PostTask(FROM_HERE, base::Bind(
&AudioManagerMac::ShutdownOnAudioThread, base::Unretained(this)));
}
Shutdown();
}
bool AudioManagerMac::HasAudioOutputDevices() {
return HasAudioHardware(kAudioHardwarePropertyDefaultOutputDevice);
}
bool AudioManagerMac::HasAudioInputDevices() {
return HasAudioHardware(kAudioHardwarePropertyDefaultInputDevice);
}
// TODO(xians): There are several places on the OSX specific code which
// could benefit from these helper functions.
bool AudioManagerMac::GetDefaultInputDevice(AudioDeviceID* device) {
return GetDefaultDevice(device, true);
}
bool AudioManagerMac::GetDefaultOutputDevice(AudioDeviceID* device) {
return GetDefaultDevice(device, false);
}
bool AudioManagerMac::GetDefaultDevice(AudioDeviceID* device, bool input) {
CHECK(device);
// Obtain the current output device selected by the user.
AudioObjectPropertyAddress pa;
pa.mSelector = input ? kAudioHardwarePropertyDefaultInputDevice :
kAudioHardwarePropertyDefaultOutputDevice;
pa.mScope = kAudioObjectPropertyScopeGlobal;
pa.mElement = kAudioObjectPropertyElementMaster;
UInt32 size = sizeof(*device);
OSStatus result = AudioObjectGetPropertyData(kAudioObjectSystemObject,
&pa,
0,
0,
&size,
device);
if ((result != kAudioHardwareNoError) || (*device == kAudioDeviceUnknown)) {
DLOG(ERROR) << "Error getting default AudioDevice.";
return false;
}
return true;
}
bool AudioManagerMac::GetDefaultOutputChannels(int* channels) {
AudioDeviceID device;
if (!GetDefaultOutputDevice(&device))
return false;
return GetDeviceChannels(device, kAudioDevicePropertyScopeOutput, channels);
}
bool AudioManagerMac::GetDeviceChannels(AudioDeviceID device,
AudioObjectPropertyScope scope,
int* channels) {
CHECK(channels);
// Get stream configuration.
AudioObjectPropertyAddress pa;
pa.mSelector = kAudioDevicePropertyStreamConfiguration;
pa.mScope = scope;
pa.mElement = kAudioObjectPropertyElementMaster;
UInt32 size;
OSStatus result = AudioObjectGetPropertyDataSize(device, &pa, 0, 0, &size);
if (result != noErr || !size)
return false;
// Allocate storage.
scoped_ptr<uint8[]> list_storage(new uint8[size]);
AudioBufferList& buffer_list =
*reinterpret_cast<AudioBufferList*>(list_storage.get());
result = AudioObjectGetPropertyData(device, &pa, 0, 0, &size, &buffer_list);
if (result != noErr)
return false;
// Determine number of input channels.
int channels_per_frame = buffer_list.mNumberBuffers > 0 ?
buffer_list.mBuffers[0].mNumberChannels : 0;
if (channels_per_frame == 1 && buffer_list.mNumberBuffers > 1) {
// Non-interleaved.
*channels = buffer_list.mNumberBuffers;
} else {
// Interleaved.
*channels = channels_per_frame;
}
return true;
}
int AudioManagerMac::HardwareSampleRateForDevice(AudioDeviceID device_id) {
Float64 nominal_sample_rate;
UInt32 info_size = sizeof(nominal_sample_rate);
static const AudioObjectPropertyAddress kNominalSampleRateAddress = {
kAudioDevicePropertyNominalSampleRate,
kAudioObjectPropertyScopeGlobal,
kAudioObjectPropertyElementMaster
};
OSStatus result = AudioObjectGetPropertyData(device_id,
&kNominalSampleRateAddress,
0,
0,
&info_size,
&nominal_sample_rate);
if (result != noErr) {
OSSTATUS_DLOG(WARNING, result)
<< "Could not get default sample rate for device: " << device_id;
return 0;
}
return static_cast<int>(nominal_sample_rate);
}
int AudioManagerMac::HardwareSampleRate() {
// Determine the default output device's sample-rate.
AudioDeviceID device_id = kAudioObjectUnknown;
if (!GetDefaultOutputDevice(&device_id))
return kFallbackSampleRate;
return HardwareSampleRateForDevice(device_id);
}
void AudioManagerMac::GetAudioInputDeviceNames(
media::AudioDeviceNames* device_names) {
DCHECK(device_names->empty());
GetAudioDeviceInfo(true, device_names);
}
void AudioManagerMac::GetAudioOutputDeviceNames(
media::AudioDeviceNames* device_names) {
DCHECK(device_names->empty());
GetAudioDeviceInfo(false, device_names);
}
AudioParameters AudioManagerMac::GetInputStreamParameters(
const std::string& device_id) {
AudioDeviceID device = GetAudioDeviceIdByUId(true, device_id);
if (device == kAudioObjectUnknown) {
DLOG(ERROR) << "Invalid device " << device_id;
return AudioParameters(
AudioParameters::AUDIO_PCM_LOW_LATENCY, CHANNEL_LAYOUT_STEREO,
kFallbackSampleRate, 16, ChooseBufferSize(true, kFallbackSampleRate));
}
int channels = 0;
ChannelLayout channel_layout = CHANNEL_LAYOUT_STEREO;
if (GetDeviceChannels(device, kAudioDevicePropertyScopeInput, &channels) &&
channels <= 2) {
channel_layout = GuessChannelLayout(channels);
} else {
DLOG(ERROR) << "Failed to get the device channels, use stereo as default "
<< "for device " << device_id;
}
int sample_rate = HardwareSampleRateForDevice(device);
if (!sample_rate)
sample_rate = kFallbackSampleRate;
// Due to the sharing of the input and output buffer sizes, we need to choose
// the input buffer size based on the output sample rate. See
// http://crbug.com/154352.
const int buffer_size = ChooseBufferSize(true, sample_rate);
// TODO(xians): query the native channel layout for the specific device.
return AudioParameters(
AudioParameters::AUDIO_PCM_LOW_LATENCY, channel_layout,
sample_rate, 16, buffer_size);
}
std::string AudioManagerMac::GetAssociatedOutputDeviceID(
const std::string& input_device_id) {
AudioDeviceID device = GetAudioDeviceIdByUId(true, input_device_id);
if (device == kAudioObjectUnknown)
return std::string();
UInt32 size = 0;
AudioObjectPropertyAddress pa = {
kAudioDevicePropertyRelatedDevices,
kAudioDevicePropertyScopeOutput,
kAudioObjectPropertyElementMaster
};
OSStatus result = AudioObjectGetPropertyDataSize(device, &pa, 0, 0, &size);
if (result || !size)
return std::string();
int device_count = size / sizeof(AudioDeviceID);
scoped_ptr<AudioDeviceID, base::FreeDeleter>
devices(static_cast<AudioDeviceID*>(malloc(size)));
result = AudioObjectGetPropertyData(
device, &pa, 0, NULL, &size, devices.get());
if (result)
return std::string();
std::vector<std::string> associated_devices;
for (int i = 0; i < device_count; ++i) {
// Get the number of output channels of the device.
pa.mSelector = kAudioDevicePropertyStreams;
size = 0;
result = AudioObjectGetPropertyDataSize(devices.get()[i],
&pa,
0,
NULL,
&size);
if (result || !size)
continue; // Skip if there aren't any output channels.
// Get device UID.
CFStringRef uid = NULL;
size = sizeof(uid);
pa.mSelector = kAudioDevicePropertyDeviceUID;
result = AudioObjectGetPropertyData(devices.get()[i],
&pa,
0,
NULL,
&size,
&uid);
if (result || !uid)
continue;
std::string ret(base::SysCFStringRefToUTF8(uid));
CFRelease(uid);
associated_devices.push_back(ret);
}
// No matching device found.
if (associated_devices.empty())
return std::string();
// Return the device if there is only one associated device.
if (associated_devices.size() == 1)
return associated_devices[0];
// When there are multiple associated devices, we currently do not have a way
// to detect if a device (e.g. a digital output device) is actually connected
// to an endpoint, so we cannot randomly pick a device.
// We pick the device iff the associated device is the default output device.
const std::string default_device = GetDefaultOutputDeviceID();
for (std::vector<std::string>::const_iterator iter =
associated_devices.begin();
iter != associated_devices.end(); ++iter) {
if (default_device == *iter)
return *iter;
}
// Failed to figure out which is the matching device, return an emtpy string.
return std::string();
}
AudioOutputStream* AudioManagerMac::MakeLinearOutputStream(
const AudioParameters& params) {
return MakeLowLatencyOutputStream(params, std::string());
}
AudioOutputStream* AudioManagerMac::MakeLowLatencyOutputStream(
const AudioParameters& params,
const std::string& device_id) {
AudioDeviceID device = GetAudioDeviceIdByUId(false, device_id);
if (device == kAudioObjectUnknown) {
DLOG(ERROR) << "Failed to open output device: " << device_id;
return NULL;
}
// Lazily create the audio device listener on the first stream creation.
if (!output_device_listener_) {
// NOTE: Use BindToCurrentLoop() to ensure the callback is always PostTask'd
// even if OSX calls us on the right thread. Some CoreAudio drivers will
// fire the callbacks during stream creation, leading to re-entrancy issues
// otherwise. See http://crbug.com/349604
output_device_listener_.reset(
new AudioDeviceListenerMac(BindToCurrentLoop(base::Bind(
&AudioManagerMac::HandleDeviceChanges, base::Unretained(this)))));
// Only set the current output device for the default device.
if (device_id == AudioManagerBase::kDefaultDeviceId || device_id.empty())
current_output_device_ = device;
// Just use the current sample rate since we don't allow non-native sample
// rates on OSX.
current_sample_rate_ = params.sample_rate();
}
AudioOutputStream* stream = new AUHALStream(this, params, device);
output_streams_.push_back(stream);
return stream;
}
std::string AudioManagerMac::GetDefaultOutputDeviceID() {
AudioDeviceID device_id = kAudioObjectUnknown;
if (!GetDefaultOutputDevice(&device_id))
return std::string();
const AudioObjectPropertyAddress property_address = {
kAudioDevicePropertyDeviceUID,
kAudioObjectPropertyScopeGlobal,
kAudioObjectPropertyElementMaster
};
CFStringRef device_uid = NULL;
UInt32 size = sizeof(device_uid);
OSStatus status = AudioObjectGetPropertyData(device_id,
&property_address,
0,
NULL,
&size,
&device_uid);
if (status != kAudioHardwareNoError || !device_uid)
return std::string();
std::string ret(base::SysCFStringRefToUTF8(device_uid));
CFRelease(device_uid);
return ret;
}
AudioInputStream* AudioManagerMac::MakeLinearInputStream(
const AudioParameters& params, const std::string& device_id) {
DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
AudioInputStream* stream = new PCMQueueInAudioInputStream(this, params);
input_streams_.push_back(stream);
return stream;
}
AudioInputStream* AudioManagerMac::MakeLowLatencyInputStream(
const AudioParameters& params, const std::string& device_id) {
DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
// Gets the AudioDeviceID that refers to the AudioInputDevice with the device
// unique id. This AudioDeviceID is used to set the device for Audio Unit.
AudioDeviceID audio_device_id = GetAudioDeviceIdByUId(true, device_id);
AudioInputStream* stream = NULL;
if (audio_device_id != kAudioObjectUnknown) {
stream = new AUAudioInputStream(this, params, audio_device_id);
input_streams_.push_back(stream);
}
return stream;
}
AudioParameters AudioManagerMac::GetPreferredOutputStreamParameters(
const std::string& output_device_id,
const AudioParameters& input_params) {
const AudioDeviceID device = GetAudioDeviceIdByUId(false, output_device_id);
if (device == kAudioObjectUnknown) {
DLOG(ERROR) << "Invalid output device " << output_device_id;
return input_params.IsValid() ? input_params : AudioParameters(
AudioParameters::AUDIO_PCM_LOW_LATENCY, CHANNEL_LAYOUT_STEREO,
kFallbackSampleRate, 16, ChooseBufferSize(false, kFallbackSampleRate));
}
const bool has_valid_input_params = input_params.IsValid();
const int hardware_sample_rate = HardwareSampleRateForDevice(device);
// Allow pass through buffer sizes. If concurrent input and output streams
// exist, they will use the smallest buffer size amongst them. As such, each
// stream must be able to FIFO requests appropriately when this happens.
int buffer_size = ChooseBufferSize(false, hardware_sample_rate);
if (has_valid_input_params) {
buffer_size =
std::min(kMaximumInputOutputBufferSize,
std::max(input_params.frames_per_buffer(), buffer_size));
}
int hardware_channels;
if (!GetDeviceChannels(device, kAudioDevicePropertyScopeOutput,
&hardware_channels)) {
hardware_channels = 2;
}
// Use the input channel count and channel layout if possible. Let OSX take
// care of remapping the channels; this lets user specified channel layouts
// work correctly.
int output_channels = input_params.channels();
ChannelLayout channel_layout = input_params.channel_layout();
if (!has_valid_input_params || output_channels > hardware_channels) {
output_channels = hardware_channels;
channel_layout = GuessChannelLayout(output_channels);
if (channel_layout == CHANNEL_LAYOUT_UNSUPPORTED)
channel_layout = CHANNEL_LAYOUT_DISCRETE;
}
return AudioParameters(
AudioParameters::AUDIO_PCM_LOW_LATENCY, channel_layout, output_channels,
hardware_sample_rate, 16, buffer_size, AudioParameters::NO_EFFECTS);
}
void AudioManagerMac::InitializeOnAudioThread() {
DCHECK(GetTaskRunner()->BelongsToCurrentThread());
power_observer_.reset(new AudioPowerObserver());
}
void AudioManagerMac::ShutdownOnAudioThread() {
DCHECK(GetTaskRunner()->BelongsToCurrentThread());
output_device_listener_.reset();
power_observer_.reset();
// Since CoreAudio calls have to run on the UI thread and browser shutdown
// doesn't wait for outstanding tasks to complete, we may have input/output
// streams still running at shutdown.
//
// To avoid calls into destructed classes, we need to stop the OS callbacks
// by stopping the streams. Note: The streams are leaked since process
// destruction is imminent.
//
// See http://crbug.com/354139 for crash details.
StopStreams(&input_streams_);
StopStreams(&output_streams_);
}
void AudioManagerMac::HandleDeviceChanges() {
DCHECK(GetTaskRunner()->BelongsToCurrentThread());
const int new_sample_rate = HardwareSampleRate();
AudioDeviceID new_output_device;
GetDefaultOutputDevice(&new_output_device);
if (current_sample_rate_ == new_sample_rate &&
current_output_device_ == new_output_device)
return;
current_sample_rate_ = new_sample_rate;
current_output_device_ = new_output_device;
NotifyAllOutputDeviceChangeListeners();
}
int AudioManagerMac::ChooseBufferSize(bool is_input, int sample_rate) {
// kMinimumInputOutputBufferSize is too small for the output side because
// CoreAudio can get into under-run if the renderer fails delivering data
// to the browser within the allowed time by the OS. The workaround is to
// use 256 samples as the default output buffer size for sample rates
// smaller than 96KHz.
// TODO(xians): Remove this workaround after WebAudio supports user defined
// buffer size. See https://github.com/WebAudio/web-audio-api/issues/348
// for details.
int buffer_size = is_input ?
kMinimumInputOutputBufferSize : 2 * kMinimumInputOutputBufferSize;
const int user_buffer_size = GetUserBufferSize();
if (user_buffer_size) {
buffer_size = user_buffer_size;
} else if (sample_rate > 48000) {
// The default buffer size is too small for higher sample rates and may lead
// to glitching. Adjust upwards by multiples of the default size.
if (sample_rate <= 96000)
buffer_size = 2 * kMinimumInputOutputBufferSize;
else if (sample_rate <= 192000)
buffer_size = 4 * kMinimumInputOutputBufferSize;
}
return buffer_size;
}
bool AudioManagerMac::ShouldDeferStreamStart() {
DCHECK(GetTaskRunner()->BelongsToCurrentThread());
return power_observer_->ShouldDeferStreamStart();
}
void AudioManagerMac::ReleaseOutputStream(AudioOutputStream* stream) {
output_streams_.remove(stream);
AudioManagerBase::ReleaseOutputStream(stream);
}
void AudioManagerMac::ReleaseInputStream(AudioInputStream* stream) {
input_streams_.remove(stream);
AudioManagerBase::ReleaseInputStream(stream);
}
AudioManager* CreateAudioManager(AudioLogFactory* audio_log_factory) {
return new AudioManagerMac(audio_log_factory);
}
} // namespace media