CameraPreviewImageSource empty preview frame

问题

I made cut and paste of the code below about how to use CameraPreviewImageSource and access to preview buffer frames, but do not work and it seems the frame buffer size is 0x0 reading the value of IImageSize parameter of OnPreviewFrameAvailable event.

How to get preview buffer of MediaCapture - Universal app

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {            
        InitializeAsync();
    }

    public async void InitializeAsync()
    {            
        _cameraPreviewImageSource = new CameraPreviewImageSource();  
        await _cameraPreviewImageSource.InitializeAsync(string.Empty);
        var properties = await _cameraPreviewImageSource.StartPreviewAsync();

        var width = 640.0;
        var height = 480;
        _writeableBitmap = new WriteableBitmap((int)width, (int)height);

        _writeableBitmapRenderer = new WriteableBitmapRenderer(_cameraPreviewImageSource, _writeableBitmap);

        Initialized = true;

        _cameraPreviewImageSource.PreviewFrameAvailable += OnPreviewFrameAvailable;
    }

    private async void OnPreviewFrameAvailable(IImageSize args)
    {
        System.Diagnostics.Debug.WriteLine("ww:"+args.Size.Width+" hh:"+args.Size.Height);

        // Prevent multiple rendering attempts at once
        if (Initialized && !_isRendering)
        {
            _isRendering = true;    
            try
            {                    
                await _writeableBitmapRenderer.RenderAsync();                   
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine("\n\n"+ex.Message);
                System.Diagnostics.Debug.WriteLine(ex.StackTrace);
            }
            _isRendering = false;
        }
    }

Capabilities (webcam & microphone) on Package.appxmanifest has been selected

Implementing CameraPreviewImageSource on a Silverlight app works great!

回答1:

I am afraid you are (were) seeing a bug in Lumia Imaging SDK 2.0.184. The problem only occured on some camera models and only on 8.1/universal applications. Silverlight applications were not affected by the problem.

The bug has been fixed in the newly released Lumia Imaging SDK 2.0.208. From release notes:

Fixed ArgumentOutOfRangeException being thrown by CameraPreviewImageSource when used with certain camera models.

来源：https://stackoverflow.com/questions/28703586/camerapreviewimagesource-empty-preview-frame