如何判断相机是否正在被其他进程使用? [英] How can I tell if the camera is in use by another process?

问题描述

在OS X中，如何确定其他应用程序或进程正在使用相机或麦克风?除非其他应用程序已锁定该设备，否则以下内容似乎不起作用.

In OS X, how can I tell if the camera or microphone is in use by another application or process? The following doesn't seem to work unless the other application has locked the device.

NSArray *devices = [AVCaptureDevice devices];

for (AVCaptureDevice *device in devices) {
    NSLog(@"In use by other application %hhd", [device isInUseByAnotherApplication]);
}

推荐答案

您可以使用CoreAudio来检查是否正在使用麦克风.

You can use CoreAudio to check if microphone is in use or not.

AudioObjectPropertyAddress propertyAddress = {kAudioHardwarePropertyDevices，kAudioObjectPropertyScopeGlobal，kAudioObjectPropertyElementMaster};

UInt32 dataSize = 0;
OSStatus status = AudioObjectGetPropertyDataSize(kAudioObjectSystemObject, &propertyAddress, 0, NULL, &dataSize);
if(kAudioHardwareNoError != status) {
    fprintf(stderr, "AudioObjectGetPropertyDataSize (kAudioHardwarePropertyDevices) failed: %i\n", status);
    //return NULL;
    return;
}

UInt32 deviceCount = (UInt32)(dataSize / sizeof(AudioDeviceID));

AudioDeviceID *audioDevices = (AudioDeviceID*)(malloc(dataSize));
if(NULL == audioDevices) {
    fputs("Unable to allocate memory", stderr);
    return;
}

status = AudioObjectGetPropertyData(kAudioObjectSystemObject, &propertyAddress, 0, NULL, &dataSize, audioDevices);
if(kAudioHardwareNoError != status) {
    fprintf(stderr, "AudioObjectGetPropertyData (kAudioHardwarePropertyDevices) failed: %i\n", status);
    free(audioDevices), audioDevices = NULL;
    return ;
}

CFMutableArrayRef inputDeviceArray = CFArrayCreateMutable(kCFAllocatorDefault, deviceCount, &kCFTypeArrayCallBacks);
if(NULL == inputDeviceArray) {
    fputs("CFArrayCreateMutable failed", stderr);
    free(audioDevices), audioDevices = NULL;
    return ;
}`

现在遍历所有设备并获取属性数据 kAudioDevicePropertyDeviceIsRunningSomewhere

Now Iterate through all the devices and fetch property data kAudioDevicePropertyDeviceIsRunningSomewhere

CFBooleanRef deviceIsRunning = NULL;dataSize = sizeof(deviceIsRunning);propertyAddress.mSelector = kAudioDevicePropertyDeviceIsRunningSomewhere;状态= AudioObjectGetPropertyData(audioDevices [i]，& propertyAddress，0，NULL，& dataSize，& deviceIsRunning);

检查deviceIsRunning变量.

Check deviceIsRunning variable.

我对视频设备一无所知.但是，如果我找到解决办法，我将更新我的答案.

I don't have idea about video device. But i will update my answer if i find some solution.

希望获得帮助.

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