c++ - 如何在 Mac OS 上获取视频捕获设备(网络摄像头)列表？ (C++)

Question

所以我只需要一个简单的列表——当前可用的视频捕获设备(网络摄像头)的列表。我在简单或 C++ 控制台应用程序中需要它。通过列表，我的意思是像这样的控制台输出:

1) Asus Web Camera
2) Sony Web Camera

所以这看起来很简单，但我有一个要求 - 尽可能多地使用 native 操作系统 api - 没有外部库 - 毕竟 - 我们想要的只是打印出一个列表 - 而不是飞上月球!)(和请不要使用 Objective-C - 纯 C/C++)

如何做这样的事情？

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同样来自这个系列:

• How to get a list of video capture devices on linux?和 special details on getting cameras NAMES有正确的、经过测试的答案
• How to get a list of video capture devices on Mac OS?正确，尚未通过我的答案进行测试
• How to get a list of video capture devices on windows?有正确的、经过测试的答案
• How to get a list video capture devices NAMES using Qt (crossplatform)?

Answer 1

您需要使用 SGGetChannelDeviceList，它是 QuickTime C API 的一部分。每个设备可以有多个输入。正确的解析方式是这样的:

    // first get a video channel from the sequence grabber

   ComponentDescription    theDesc;
   Component               sgCompID;
   ComponentResult         result;
   theDesc.componentType           = SeqGrabComponentType;
   theDesc.componentSubType        = 0L;
   theDesc.componentManufacturer   = 'appl';
   theDesc.componentFlags          = 0L;
   theDesc.componentFlagsMask      = 0L;   
   sgCompID = FindNextComponent (NULL, &theDesc);
   seqGrabber = OpenComponent (sgCompID);
   result = SGInitialize (seqGrabber);
   result = SGNewChannel (seqGrabber, VideoMediaType, &videoChannel);
   SGDeviceList  theDevices;
   SGGetChannelDeviceList(videoChannel, sgDeviceListDontCheckAvailability | sgDeviceListIncludeInputs, &theDevices);

    if (theDevices)
    {
        int theDeviceIndex;
        for (theDeviceIndex = 0; theDeviceIndex != (*theDevices)->count; ++theDeviceIndex)
        {
            SGDeviceName theDeviceEntry = (*theDevices)->entry[theDeviceIndex];
            // name of device is a pstring in theDeviceEntry.name

        SGDeviceInputList theInputs = theDeviceEntry.inputs;
            if (theInputs != NULL)
            {
                int theInputIndex;
                for ( theInputIndex = 0; theInputIndex != (*theInputs)->count; ++theInputIndex)
                {
                    SGDeviceInputName theInput = (*theInputs)->entry[theInputIndex];
                    // name of input is a pstring in theInput.name
                }
            }
        }       
    }