C# MediaCapture UnuthorizedAccessException or no supported formats after Windows Update

Question

Every since I did an update on my Windows machine, I can no longer use the camera in my UWP application that uses the MediaCapture class.

Origninally, I was getting an UnuthorizedAccessException when trying to call the InitializeAsync() function but, I managed to fix this by adding the EnableFrameServerMode to my register (via this link: https://www.macecraft.com/fix-webcam-issues-windows-10-anniversary-update/)

However, since doing this, the MediaFrameSource.SupportedFormats property is empty (MediaFrameSource.SupportedFormats.Count is 0).

This is only occurring on my machine, colleagues with identical machines (same hardware and software), and different machines, are not experiencing this issue.

I'm currently running:

Windows 10 Home edition
Version 10.0.17134 Build 17134

I'm building the app with Xamarin.Forms using Visual Studio version 15.9.4. The Target Version for the app is Windows 10.0 Build 16299 (Min Version is the same).

Here is my code from my ViewRenderer:

var frameSourceGroups = await MediaFrameSourceGroup.FindAllAsync();

MediaFrameSourceGroup selectedGroup = null;
MediaFrameSourceInfo colorSourceInfo = null;

foreach (var sourceGroup in frameSourceGroups)
{
    foreach (var sourceInfo in sourceGroup.SourceInfos)
    {
        if (sourceInfo.MediaStreamType == MediaStreamType.VideoRecord
            && sourceInfo.SourceKind == MediaFrameSourceKind.Color
            && sourceInfo.DeviceInformation.EnclosureLocation != null
            && sourceInfo.DeviceInformation.EnclosureLocation.Panel == Windows.Devices.Enumeration.Panel.Front)
        {
            colorSourceInfo = sourceInfo;
            break;
        }
        colorSourceInfo = sourceInfo;
    }
    if (colorSourceInfo != null)
    {
        selectedGroup = sourceGroup;
        break;
    }
    selectedGroup = sourceGroup;
}

if (selectedGroup == null || colorSourceInfo == null) return;
_mediaCapture = new MediaCapture();
var settings = new MediaCaptureInitializationSettings()
{
    SourceGroup = selectedGroup,
    SharingMode = MediaCaptureSharingMode.ExclusiveControl,
    MemoryPreference = MediaCaptureMemoryPreference.Cpu,
    StreamingCaptureMode = StreamingCaptureMode.Video
};

try
{
    await _mediaCapture.InitializeAsync(settings);
}
catch (UnauthorizedAccessException)
{
    Debug.WriteLine("The app was denied access to the camera");
    return;
}
catch (Exception ex)
{
    Debug.WriteLine("MediaCapture initialization failed: " + ex.Message);
    return;
}

If the EnableFrameServerMode is not set to 0 in my registry, I get an UnauthorizedAccessException. If it is:

MediaFrameSource colorFrameSource = null;
foreach (var keyValuePairFrameSource in _mediaCapture.FrameSources)
{
    if (keyValuePairFrameSource.Key.ToLowerInvariant().Contains(colorSourceInfo.SourceGroup.Id.ToLowerInvariant()))
    {
        colorFrameSource = keyValuePairFrameSource.Value;
    }
}

_config = ConfigurationHelper.GetConfigData();

var preferredFormat = colorFrameSource?.SupportedFormats.FirstOrDefault(format =>
    format.VideoFormat.Width == _config.CameraPreviewWidth &&
    format.VideoFormat.Height == _config.CameraPreviewHeight &&
    format.Subtype == MediaEncodingSubtypes.Nv12.ToUpper());
if (preferredFormat == null)
{
    Debug.WriteLine("Our desired format is not supported");
    return;
}

SupportedFormats List is empty, causing our preferredFormat object to be null.

If I don't return when preferredFormat is null, and do this:

var _mediaFrameReader = await _mediaCapture.CreateFrameReaderAsync(colorFrameSource, MediaEncodingSubtypes.Nv12);
_mediaFrameReader.FrameArrived += ColorFrameReader_FrameArrived;
await _mediaFrameReader.StartAsync();

I just get a screen with a black background where the camera frames should be.

Nico Zhu · Answer 1 · 2019-01-18T08:12:52.220

0

This is only occurring on my machine, colleagues with identical machines (same hardware and software), and different machines, are not experiencing this issue.

I checked your code, and it is similar as CameraFrames official code sample. I have test with LifeCam HD-3000, and it works well(No modify the registry). I thinks it is very likely that there is a problem with your hardware device. I think you could use other camera troubleshooting. For using camera you could also check this sample.

edited Jan 18 '19 at 08:12

answered Jan 18 '19 at 07:04

Nico Zhu

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Yeah, I tried the CameraFrames sample, and I'm getting the same errors. My colleague just did an update to his Windows machine, and is now experiencing the same issues. – PMARSH Jan 28 '19 at 10:30
In the end, it turned out to be my anti-virus... Kind of strange that we can bypass the initial "Access denied" exception with the registry value, maybe something to keep in mind. – PMARSH Jan 29 '19 at 08:58

C# MediaCapture UnuthorizedAccessException or no supported formats after Windows Update

1 Answers1