Windows Phone 8.1 Camera Initialisation - Access Denied Exception

问题

Using the 8.1 MediaCapture classes for Windows Phone.

Have declared the capabilities for "Audio" and "Webcam", which 90% is what would be the cause of the exception.

Kicker is, it works perfectly in the WP emulator, but breaks on an actual device.

Exact exception is here :

I have added a mountain of checks to make sure we aren't re-initializing the already initialized camera or trying to read before the initializations.. etc (as I assumed the issue was being caused by) So it is very unlikely to be that.

    private async Task InitializeCameraAsync()
    {
        if (_isInitialized)
        {
            Debug.WriteLine("Skipping unnecessary initialization");
            return;
        }

        Debug.WriteLine("Initializing camera media capture...");
        _deviceCapture = new MediaCapture();
        await _deviceCapture.InitializeAsync(new MediaCaptureInitializationSettings
        {
            VideoDeviceId = _cameraInfoCollection[_currentVideoDevice].Id,
            PhotoCaptureSource = PhotoCaptureSource.VideoPreview,
            AudioDeviceId = _microphoneInfoCollection[_currentAudioDevice].Id
            StreamingCaptureMode = StreamingCaptureMode.Video
        });
        Debug.WriteLine("Initialized camera media capture!");

        // For code completion only, unlikely to be relevant

        // Set up low-lag photo capture
        if (IsNotUsingInstantCapture)
        {
            Debug.WriteLine("Preparing low-lag photo capture");
            var imageEncoding = ImageEncodingProperties.CreateJpeg();
            imageEncoding.Width = PhotoCaptureWidth;
            imageEncoding.Height = PhotoCaptureHeight;
            _lowLagPhotoCapture = await _deviceCapture.PrepareLowLagPhotoCaptureAsync(imageEncoding);
        }

        _isInitialized = true;
        Debug.WriteLine("Initialized camera!");
    }

_mediacapture is then being bound to the .source of a xaml CaptureElement to show a preview.

回答1:

It was a temporary bug with the Windows api. It was fixed with the Windows Phone 8.1 update that was released the 24th of september 2014.

来源：https://stackoverflow.com/questions/25224102/windows-phone-8-1-camera-initialisation-access-denied-exception