基于Qt和Media Foundation 框架获取或设置UVC相机属性

获取和设置UVC相机属性可以使用Qt和Media Foundation框架。以下是一些步骤：

1. 首先，需要使用Media Foundation框架来获取UVC相机的属性。在此之前，需要确保已经正确安装了Media Foundation SDK和UVC相机驱动程序。

2. 使用Media Foundation框架中的IMFActivate接口来获取UVC相机设备的属性。可以使用以下代码：

IMFAttributes* pAttributes = NULL;
IMFActivate** ppDevices = NULL;

// Create an attribute store to specify the enumeration parameters.
HRESULT hr = MFCreateAttributes(&pAttributes, 1);

if (SUCCEEDED(hr))
{
    // Specify the enumeration parameter.
    hr = pAttributes->SetGUID(
        MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE,
        MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_GUID
    );
}

if (SUCCEEDED(hr))
{
    // Enumerate the devices.
    UINT32 count;
    hr = MFEnumDeviceSources(pAttributes, &ppDevices, &count);
}

if (SUCCEEDED(hr))
{
    // Iterate through the devices and get the properties.
    for (UINT32 i = 0; i < count; i++)
    {
        IMFAttributes* pDeviceAttributes = NULL;
        hr = ppDevices[i]->GetAttributes(&pDeviceAttributes);

        if (SUCCEEDED(hr))
        {
            // Get the device name.
            WCHAR* pName = NULL;
            UINT32 cchName;
            hr = ppDevices[i]->GetAllocatedString(MF_DEVSOURCE_ATTRIBUTE_FRIENDLY_NAME, &pName, &cchName);

            if (SUCCEEDED(hr))
            {
                wprintf(L"Device name: %s\n", pName);
                CoTaskMemFree(pName);
            }

            // Get the device ID.
            WCHAR* pId = NULL;
            UINT32 cchId;
            hr = ppDevices[i]->GetAllocatedString(MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_SYMBOLIC_LINK, &pId, &cchId);

            if (SUCCEEDED(hr))
            {
                wprintf(L"Device ID: %s\n", pId);
                CoTaskMemFree(pId);
            }

            // Get the device attributes.
            GUID subtype;
            UINT32 width, height, fps;
            hr = pDeviceAttributes->GetGUID(MF_MT_SUBTYPE, &subtype);

            if (SUCCEEDED(hr))
            {
                hr = MFGetAttributeSize(pDeviceAttributes, MF_MT_FRAME_SIZE, &width, &height);
            }

            if (SUCCEEDED(hr))
            {
                hr = MFGetAttributeRatio(pDeviceAttributes, MF_MT_FRAME_RATE, &fps, 1);
            }

            if (SUCCEEDED(hr))
            {
                wprintf(L"Video format: %s, %dx%d, %dfps\n", GetSubtypeName(subtype), width, height, fps);
            }

            pDeviceAttributes->Release();
        }

        ppDevices[i]->Release();
    }

    CoTaskMemFree(ppDevices);
}

pAttributes->Release();

3. 上面的代码将枚举UVC相机设备并获取它们的属性，包括设备名称、设备ID和视频格式。可以根据需要设置其他属性，例如曝光时间、增益等。可以使用以下代码设置相机属性：

IMFMediaSource* pSource = NULL;
IMFAttributes* pAttributes = NULL;

// Create the media source from the device ID.
hr = MFCreateDeviceSource(pId, &pAttributes, &pSource);

if (SUCCEEDED(hr))
{
    // Set the exposure time.
    hr = pAttributes->SetUINT64(MF_VIDCAP_CAMERACONTROL_EXPOSURE, exposureTime);
}

if (SUCCEEDED(hr))
{
    // Set the gain.
    hr = pAttributes->SetUINT64(MF_VIDCAP_CAMERACONTROL_GAIN, gainValue);
}

if (SUCCEEDED(hr))
{
    // Set the white balance.
    hr = pAttributes->SetUINT32(MF_VIDCAP_CAMERACONTROL_WHITEBALANCE, whiteBalanceValue);
}

// Release the media source and attributes.
pSource->Release();
pAttributes->Release();

4. 上面的代码将设置UVC相机的曝光时间、增益和白平衡。可以根据需要设置其他属性。

希望这些代码可以帮助你获取和设置UVC相机属性。