zqz/platform-external-webrtc
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

After an audio interruption the audio unit no longer invokes its render callback, which results in a loss of audio. Restarting the audio unit post interruption fixes the issue.

Browse Source 
CL also replaces deprecated AudioSession calls with equivalent AVAudioSession ones.

BUG=3487
R=glaznev@webrtc.org, noahric@chromium.org

Review URL: https://webrtc-codereview.appspot.com/21769004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6697 4adac7df-926f-26a2-2b94-8c16560cd09d
This commit is contained in:
tkchin@webrtc.org
2014-07-15 20:20:47 +00:00
parent 47218956fc
commit 122caa51b1
8 changed files with 491 additions and 438 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
webrtc/modules/audio_device/audio_device.gypi
View File

@ -98,7 +98,7 @@
'linux/audio_mixer_manager_alsa_linux.h',
'linux/latebindingsymboltable_linux.cc',
'linux/latebindingsymboltable_linux.h',
'ios/audio_device_ios.cc',
'ios/audio_device_ios.mm',
'ios/audio_device_ios.h',
'ios/audio_device_utility_ios.cc',
'ios/audio_device_utility_ios.h',
@ -175,7 +175,7 @@
}],
],
}],
['OS=="mac" or OS=="ios"', {
['OS=="mac"', {
'link_settings': {
'libraries': [
'$(SDKROOT)/System/Library/Frameworks/AudioToolbox.framework',
@ -183,6 +183,19 @@
],
},
}],
['OS=="ios"', {
'xcode_settings': {
'CLANG_ENABLE_OBJC_ARC': 'YES',
},
'link_settings': {
'xcode_settings': {
'OTHER_LDFLAGS': [
'-framework AudioToolbox',
'-framework AVFoundation',
],
},
},
}],
['OS=="win"', {
'link_settings': {
'libraries': [

8
webrtc/modules/audio_device/audio_device_impl.cc
View File

@ -349,15 +349,15 @@ int32_t AudioDeviceModuleImpl::CreatePlatformSpecificObjects()
#if defined(WEBRTC_IOS)
if (audioLayer == kPlatformDefaultAudio)
{
// Create *iPhone Audio* implementation
ptrAudioDevice = new AudioDeviceIPhone(Id());
// Create iOS Audio Device implementation.
ptrAudioDevice = new AudioDeviceIOS(Id());
WEBRTC_TRACE(kTraceInfo, kTraceAudioDevice, _id, "iPhone Audio APIs will be utilized");
}
if (ptrAudioDevice != NULL)
{
// Create the Mac implementation of the Device Utility.
ptrAudioDeviceUtility = new AudioDeviceUtilityIPhone(Id());
// Create iOS Device Utility implementation.
ptrAudioDeviceUtility = new AudioDeviceUtilityIOS(Id());
}
// END #if defined(WEBRTC_IOS)

16
webrtc/modules/audio_device/audio_device_utility.h
View File

@ -18,15 +18,15 @@ namespace webrtc
class AudioDeviceUtility
{
public:
static uint32_t GetTimeInMS();
static void WaitForKey();
static bool StringCompare(const char* str1,
const char* str2,
const uint32_t length);
virtual int32_t Init() = 0;
public:
static uint32_t GetTimeInMS();
static void WaitForKey();
static bool StringCompare(const char* str1,
const char* str2,
const uint32_t length);
virtual int32_t Init() = 0;
virtual ~AudioDeviceUtility() {}
virtual ~AudioDeviceUtility() {}
};
} // namespace webrtc

385
webrtc/modules/audio_device/ios/audio_device_ios.h
View File

@ -8,8 +8,8 @@
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_IPHONE_H
#define WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_IPHONE_H
#ifndef WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_IOS_H
#define WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_IOS_H
#include <AudioUnit/AudioUnit.h>
@ -32,244 +32,241 @@ const uint32_t ENGINE_PLAY_BUF_SIZE_IN_SAMPLES = (N_PLAY_SAMPLES_PER_SEC / 100);
// Number of 10 ms recording blocks in recording buffer
const uint16_t N_REC_BUFFERS = 20;
class AudioDeviceIPhone : public AudioDeviceGeneric {
public:
AudioDeviceIPhone(const int32_t id);
~AudioDeviceIPhone();
class AudioDeviceIOS : public AudioDeviceGeneric {
public:
AudioDeviceIOS(const int32_t id);
~AudioDeviceIOS();
// Retrieve the currently utilized audio layer
virtual int32_t
ActiveAudioLayer(AudioDeviceModule::AudioLayer& audioLayer) const;
// Retrieve the currently utilized audio layer
virtual int32_t ActiveAudioLayer(
AudioDeviceModule::AudioLayer& audioLayer) const;
// Main initializaton and termination
virtual int32_t Init();
virtual int32_t Terminate();
virtual bool Initialized() const;
// Main initializaton and termination
virtual int32_t Init();
virtual int32_t Terminate();
virtual bool Initialized() const;
// Device enumeration
virtual int16_t PlayoutDevices();
virtual int16_t RecordingDevices();
virtual int32_t PlayoutDeviceName(uint16_t index,
// Device enumeration
virtual int16_t PlayoutDevices();
virtual int16_t RecordingDevices();
virtual int32_t PlayoutDeviceName(uint16_t index,
char name[kAdmMaxDeviceNameSize],
char guid[kAdmMaxGuidSize]);
virtual int32_t RecordingDeviceName(uint16_t index,
char name[kAdmMaxDeviceNameSize],
char guid[kAdmMaxGuidSize]);
virtual int32_t RecordingDeviceName(uint16_t index,
char name[kAdmMaxDeviceNameSize],
char guid[kAdmMaxGuidSize]);
// Device selection
virtual int32_t SetPlayoutDevice(uint16_t index);
virtual int32_t
SetPlayoutDevice(AudioDeviceModule::WindowsDeviceType device);
virtual int32_t SetRecordingDevice(uint16_t index);
virtual int32_t SetRecordingDevice(
AudioDeviceModule::WindowsDeviceType device);
// Device selection
virtual int32_t SetPlayoutDevice(uint16_t index);
virtual int32_t SetPlayoutDevice(AudioDeviceModule::WindowsDeviceType device);
virtual int32_t SetRecordingDevice(uint16_t index);
virtual int32_t SetRecordingDevice(
AudioDeviceModule::WindowsDeviceType device);
// Audio transport initialization
virtual int32_t PlayoutIsAvailable(bool& available);
virtual int32_t InitPlayout();
virtual bool PlayoutIsInitialized() const;
virtual int32_t RecordingIsAvailable(bool& available);
virtual int32_t InitRecording();
virtual bool RecordingIsInitialized() const;
// Audio transport initialization
virtual int32_t PlayoutIsAvailable(bool& available);
virtual int32_t InitPlayout();
virtual bool PlayoutIsInitialized() const;
virtual int32_t RecordingIsAvailable(bool& available);
virtual int32_t InitRecording();
virtual bool RecordingIsInitialized() const;
// Audio transport control
virtual int32_t StartPlayout();
virtual int32_t StopPlayout();
virtual bool Playing() const;
virtual int32_t StartRecording();
virtual int32_t StopRecording();
virtual bool Recording() const;
// Audio transport control
virtual int32_t StartPlayout();
virtual int32_t StopPlayout();
virtual bool Playing() const;
virtual int32_t StartRecording();
virtual int32_t StopRecording();
virtual bool Recording() const;
// Microphone Automatic Gain Control (AGC)
virtual int32_t SetAGC(bool enable);
virtual bool AGC() const;
// Microphone Automatic Gain Control (AGC)
virtual int32_t SetAGC(bool enable);
virtual bool AGC() const;
// Volume control based on the Windows Wave API (Windows only)
virtual int32_t SetWaveOutVolume(uint16_t volumeLeft, uint16_t volumeRight);
virtual int32_t WaveOutVolume(uint16_t& volumeLeft,
uint16_t& volumeRight) const;
// Volume control based on the Windows Wave API (Windows only)
virtual int32_t SetWaveOutVolume(uint16_t volumeLeft, uint16_t volumeRight);
virtual int32_t WaveOutVolume(uint16_t& volumeLeft,
uint16_t& volumeRight) const;
// Audio mixer initialization
virtual int32_t InitSpeaker();
virtual bool SpeakerIsInitialized() const;
virtual int32_t InitMicrophone();
virtual bool MicrophoneIsInitialized() const;
// Audio mixer initialization
virtual int32_t InitSpeaker();
virtual bool SpeakerIsInitialized() const;
virtual int32_t InitMicrophone();
virtual bool MicrophoneIsInitialized() const;
// Speaker volume controls
virtual int32_t SpeakerVolumeIsAvailable(bool& available);
virtual int32_t SetSpeakerVolume(uint32_t volume);
virtual int32_t SpeakerVolume(uint32_t& volume) const;
virtual int32_t MaxSpeakerVolume(uint32_t& maxVolume) const;
virtual int32_t MinSpeakerVolume(uint32_t& minVolume) const;
virtual int32_t SpeakerVolumeStepSize(uint16_t& stepSize) const;
// Speaker volume controls
virtual int32_t SpeakerVolumeIsAvailable(bool& available);
virtual int32_t SetSpeakerVolume(uint32_t volume);
virtual int32_t SpeakerVolume(uint32_t& volume) const;
virtual int32_t MaxSpeakerVolume(uint32_t& maxVolume) const;
virtual int32_t MinSpeakerVolume(uint32_t& minVolume) const;
virtual int32_t SpeakerVolumeStepSize(uint16_t& stepSize) const;
// Microphone volume controls
virtual int32_t MicrophoneVolumeIsAvailable(bool& available);
virtual int32_t SetMicrophoneVolume(uint32_t volume);
virtual int32_t MicrophoneVolume(uint32_t& volume) const;
virtual int32_t MaxMicrophoneVolume(uint32_t& maxVolume) const;
virtual int32_t MinMicrophoneVolume(uint32_t& minVolume) const;
virtual int32_t
MicrophoneVolumeStepSize(uint16_t& stepSize) const;
// Microphone volume controls
virtual int32_t MicrophoneVolumeIsAvailable(bool& available);
virtual int32_t SetMicrophoneVolume(uint32_t volume);
virtual int32_t MicrophoneVolume(uint32_t& volume) const;
virtual int32_t MaxMicrophoneVolume(uint32_t& maxVolume) const;
virtual int32_t MinMicrophoneVolume(uint32_t& minVolume) const;
virtual int32_t MicrophoneVolumeStepSize(uint16_t& stepSize) const;
// Microphone mute control
virtual int32_t MicrophoneMuteIsAvailable(bool& available);
virtual int32_t SetMicrophoneMute(bool enable);
virtual int32_t MicrophoneMute(bool& enabled) const;
// Microphone mute control
virtual int32_t MicrophoneMuteIsAvailable(bool& available);
virtual int32_t SetMicrophoneMute(bool enable);
virtual int32_t MicrophoneMute(bool& enabled) const;
// Speaker mute control
virtual int32_t SpeakerMuteIsAvailable(bool& available);
virtual int32_t SetSpeakerMute(bool enable);
virtual int32_t SpeakerMute(bool& enabled) const;
// Speaker mute control
virtual int32_t SpeakerMuteIsAvailable(bool& available);
virtual int32_t SetSpeakerMute(bool enable);
virtual int32_t SpeakerMute(bool& enabled) const;
// Microphone boost control
virtual int32_t MicrophoneBoostIsAvailable(bool& available);
virtual int32_t SetMicrophoneBoost(bool enable);
virtual int32_t MicrophoneBoost(bool& enabled) const;
// Microphone boost control
virtual int32_t MicrophoneBoostIsAvailable(bool& available);
virtual int32_t SetMicrophoneBoost(bool enable);
virtual int32_t MicrophoneBoost(bool& enabled) const;
// Stereo support
virtual int32_t StereoPlayoutIsAvailable(bool& available);
virtual int32_t SetStereoPlayout(bool enable);
virtual int32_t StereoPlayout(bool& enabled) const;
virtual int32_t StereoRecordingIsAvailable(bool& available);
virtual int32_t SetStereoRecording(bool enable);
virtual int32_t StereoRecording(bool& enabled) const;
// Stereo support
virtual int32_t StereoPlayoutIsAvailable(bool& available);
virtual int32_t SetStereoPlayout(bool enable);
virtual int32_t StereoPlayout(bool& enabled) const;
virtual int32_t StereoRecordingIsAvailable(bool& available);
virtual int32_t SetStereoRecording(bool enable);
virtual int32_t StereoRecording(bool& enabled) const;
// Delay information and control
virtual int32_t
SetPlayoutBuffer(const AudioDeviceModule::BufferType type,
uint16_t sizeMS);
virtual int32_t PlayoutBuffer(AudioDeviceModule::BufferType& type,
uint16_t& sizeMS) const;
virtual int32_t PlayoutDelay(uint16_t& delayMS) const;
virtual int32_t RecordingDelay(uint16_t& delayMS) const;
// Delay information and control
virtual int32_t SetPlayoutBuffer(const AudioDeviceModule::BufferType type,
uint16_t sizeMS);
virtual int32_t PlayoutBuffer(AudioDeviceModule::BufferType& type,
uint16_t& sizeMS) const;
virtual int32_t PlayoutDelay(uint16_t& delayMS) const;
virtual int32_t RecordingDelay(uint16_t& delayMS) const;
// CPU load
virtual int32_t CPULoad(uint16_t& load) const;
// CPU load
virtual int32_t CPULoad(uint16_t& load) const;
public:
virtual bool PlayoutWarning() const;
virtual bool PlayoutError() const;
virtual bool RecordingWarning() const;
virtual bool RecordingError() const;
virtual void ClearPlayoutWarning();
virtual void ClearPlayoutError();
virtual void ClearRecordingWarning();
virtual void ClearRecordingError();
public:
virtual bool PlayoutWarning() const;
virtual bool PlayoutError() const;
virtual bool RecordingWarning() const;
virtual bool RecordingError() const;
virtual void ClearPlayoutWarning();
virtual void ClearPlayoutError();
virtual void ClearRecordingWarning();
virtual void ClearRecordingError();
public:
virtual void AttachAudioBuffer(AudioDeviceBuffer* audioBuffer);
public:
virtual void AttachAudioBuffer(AudioDeviceBuffer* audioBuffer);
// Reset Audio Deivce (for mobile devices only)
virtual int32_t ResetAudioDevice();
// Reset Audio Device (for mobile devices only)
virtual int32_t ResetAudioDevice();
// enable or disable loud speaker (for iphone only)
virtual int32_t SetLoudspeakerStatus(bool enable);
virtual int32_t GetLoudspeakerStatus(bool& enabled) const;
// enable or disable loud speaker (for iphone only)
virtual int32_t SetLoudspeakerStatus(bool enable);
virtual int32_t GetLoudspeakerStatus(bool& enabled) const;
private:
void Lock() {
_critSect.Enter();
}
private:
void Lock() {
_critSect.Enter();
}
void UnLock() {
_critSect.Leave();
}
void UnLock() {
_critSect.Leave();
}
int32_t Id() {
return _id;
}
int32_t Id() {
return _id;
}
// Init and shutdown
int32_t InitPlayOrRecord();
int32_t ShutdownPlayOrRecord();
// Init and shutdown
int32_t InitPlayOrRecord();
int32_t ShutdownPlayOrRecord();
void UpdateRecordingDelay();
void UpdatePlayoutDelay();
void UpdateRecordingDelay();
void UpdatePlayoutDelay();
static OSStatus RecordProcess(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *timeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData);
static OSStatus PlayoutProcess(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *timeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData);
OSStatus RecordProcessImpl(AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *timeStamp,
uint32_t inBusNumber,
uint32_t inNumberFrames);
OSStatus PlayoutProcessImpl(uint32_t inNumberFrames,
static OSStatus RecordProcess(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *timeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData);
static bool RunCapture(void* ptrThis);
bool CaptureWorkerThread();
static OSStatus PlayoutProcess(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *timeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData);
private:
AudioDeviceBuffer* _ptrAudioBuffer;
OSStatus RecordProcessImpl(AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *timeStamp,
uint32_t inBusNumber,
uint32_t inNumberFrames);
CriticalSectionWrapper& _critSect;
OSStatus PlayoutProcessImpl(uint32_t inNumberFrames,
AudioBufferList *ioData);
ThreadWrapper* _captureWorkerThread;
uint32_t _captureWorkerThreadId;
static bool RunCapture(void* ptrThis);
bool CaptureWorkerThread();
int32_t _id;
private:
AudioDeviceBuffer* _ptrAudioBuffer;
AudioUnit _auVoiceProcessing;
CriticalSectionWrapper& _critSect;
private:
bool _initialized;
bool _isShutDown;
bool _recording;
bool _playing;
bool _recIsInitialized;
bool _playIsInitialized;
ThreadWrapper* _captureWorkerThread;
uint32_t _captureWorkerThreadId;
bool _recordingDeviceIsSpecified;
bool _playoutDeviceIsSpecified;
bool _micIsInitialized;
bool _speakerIsInitialized;
int32_t _id;
bool _AGC;
AudioUnit _auVoiceProcessing;
void* _audioInterruptionObserver;
// The sampling rate to use with Audio Device Buffer
uint32_t _adbSampFreq;
private:
bool _initialized;
bool _isShutDown;
bool _recording;
bool _playing;
bool _recIsInitialized;
bool _playIsInitialized;
// Delay calculation
uint32_t _recordingDelay;
uint32_t _playoutDelay;
uint32_t _playoutDelayMeasurementCounter;
uint32_t _recordingDelayHWAndOS;
uint32_t _recordingDelayMeasurementCounter;
bool _recordingDeviceIsSpecified;
bool _playoutDeviceIsSpecified;
bool _micIsInitialized;
bool _speakerIsInitialized;
// Errors and warnings count
uint16_t _playWarning;
uint16_t _playError;
uint16_t _recWarning;
uint16_t _recError;
bool _AGC;
// Playout buffer, needed for 44.0 / 44.1 kHz mismatch
int16_t _playoutBuffer[ENGINE_PLAY_BUF_SIZE_IN_SAMPLES];
uint32_t _playoutBufferUsed; // How much is filled
// The sampling rate to use with Audio Device Buffer
uint32_t _adbSampFreq;
// Recording buffers
int16_t
_recordingBuffer[N_REC_BUFFERS][ENGINE_REC_BUF_SIZE_IN_SAMPLES];
uint32_t _recordingLength[N_REC_BUFFERS];
uint32_t _recordingSeqNumber[N_REC_BUFFERS];
uint32_t _recordingCurrentSeq;
// Delay calculation
uint32_t _recordingDelay;
uint32_t _playoutDelay;
uint32_t _playoutDelayMeasurementCounter;
uint32_t _recordingDelayHWAndOS;
uint32_t _recordingDelayMeasurementCounter;
// Current total size all data in buffers, used for delay estimate
uint32_t _recordingBufferTotalSize;
// Errors and warnings count
uint16_t _playWarning;
uint16_t _playError;
uint16_t _recWarning;
uint16_t _recError;
// Playout buffer, needed for 44.0 / 44.1 kHz mismatch
int16_t _playoutBuffer[ENGINE_PLAY_BUF_SIZE_IN_SAMPLES];
uint32_t _playoutBufferUsed; // How much is filled
// Recording buffers
int16_t _recordingBuffer[N_REC_BUFFERS][ENGINE_REC_BUF_SIZE_IN_SAMPLES];
uint32_t _recordingLength[N_REC_BUFFERS];
uint32_t _recordingSeqNumber[N_REC_BUFFERS];
uint32_t _recordingCurrentSeq;
// Current total size all data in buffers, used for delay estimate
uint32_t _recordingBufferTotalSize;
};
} // namespace webrtc
#endif // MODULES_AUDIO_DEVICE_MAIN_SOURCE_MAC_AUDIO_DEVICE_IPHONE_H_
#endif // WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_IOS_H

478
webrtc/modules/audio_device/ios/audio_device_ios.cc → webrtc/modules/audio_device/ios/audio_device_ios.mm
View File

File diff suppressed because it is too large Load Diff

6
webrtc/modules/audio_device/ios/audio_device_utility_ios.cc
View File

@ -15,7 +15,7 @@
#include "webrtc/system_wrappers/interface/trace.h"
namespace webrtc {
AudioDeviceUtilityIPhone::AudioDeviceUtilityIPhone(const int32_t id)
AudioDeviceUtilityIOS::AudioDeviceUtilityIOS(const int32_t id)
:
_critSect(*CriticalSectionWrapper::CreateCriticalSection()),
_id(id),
@ -24,7 +24,7 @@ AudioDeviceUtilityIPhone::AudioDeviceUtilityIPhone(const int32_t id)
"%s created", __FUNCTION__);
}
AudioDeviceUtilityIPhone::~AudioDeviceUtilityIPhone() {
AudioDeviceUtilityIOS::~AudioDeviceUtilityIOS() {
WEBRTC_TRACE(kTraceMemory, kTraceAudioDevice, _id,
"%s destroyed", __FUNCTION__);
CriticalSectionScoped lock(&_critSect);
@ -32,7 +32,7 @@ AudioDeviceUtilityIPhone::~AudioDeviceUtilityIPhone() {
delete &_critSect;
}
int32_t AudioDeviceUtilityIPhone::Init() {
int32_t AudioDeviceUtilityIOS::Init() {
WEBRTC_TRACE(kTraceModuleCall, kTraceAudioDevice, _id,
"%s", __FUNCTION__);

18
webrtc/modules/audio_device/ios/audio_device_utility_ios.h
View File

@ -8,8 +8,8 @@
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_UTILITY_IPHONE_H
#define WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_UTILITY_IPHONE_H
#ifndef WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_UTILITY_IOS_H
#define WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_UTILITY_IOS_H
#include "webrtc/modules/audio_device/audio_device_utility.h"
#include "webrtc/modules/audio_device/include/audio_device.h"
@ -17,15 +17,15 @@
namespace webrtc {
class CriticalSectionWrapper;
class AudioDeviceUtilityIPhone: public AudioDeviceUtility {
public:
AudioDeviceUtilityIPhone(const int32_t id);
AudioDeviceUtilityIPhone();
virtual ~AudioDeviceUtilityIPhone();
class AudioDeviceUtilityIOS: public AudioDeviceUtility {
public:
AudioDeviceUtilityIOS(const int32_t id);
AudioDeviceUtilityIOS();
virtual ~AudioDeviceUtilityIOS();
virtual int32_t Init();
private:
private:
CriticalSectionWrapper& _critSect;
int32_t _id;
AudioDeviceModule::ErrorCode _lastError;
@ -33,4 +33,4 @@ private:
} // namespace webrtc
#endif // WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_UTILITY_IPHONE_H
#endif // WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_UTILITY_IOS_H

1
webrtc/modules/video_capture/ios/rtc_video_capture_ios_objc.mm
View File

@ -43,6 +43,7 @@ using namespace webrtc::videocapturemodule;
_owner = owner;
_captureId = captureId;
_captureSession = [[AVCaptureSession alloc] init];
_captureSession.usesApplicationAudioSession = NO;
_captureChanging = NO;
_captureChangingCondition = [[NSCondition alloc] init];