CODEWITHSUNDEEP
c#uwpvideo-processing
Konrad Śledziewski
Konrad Śledziewski

Reputation: 120

UWP video stream bitmaps manipulation

I coded example from https://learn.microsoft.com/en-us/windows/uwp/audio-video-camera/custom-video-effects

Part of the code:

public void ProcessFrame(ProcessVideoFrameContext context)
    {

        using (CanvasBitmap inputBitmap = CanvasBitmap.CreateFromDirect3D11Surface(canvasDevice, context.InputFrame.Direct3DSurface))
        using (CanvasRenderTarget renderTarget = CanvasRenderTarget.CreateFromDirect3D11Surface(canvasDevice, context.OutputFrame.Direct3DSurface))
        using (CanvasDrawingSession ds = renderTarget.CreateDrawingSession())
        {

            var gaussianBlurEffect = new GaussianBlurEffect
            {
                Source = inputBitmap,
                BlurAmount = (float)BlurAmount,
                Optimization = EffectOptimization.Speed
            };

            ds.DrawImage(gaussianBlurEffect);
        }
    }

The problem is: i want to draw points (bitmaps) on frames but i have no idea how to pass specific coord to ProcessFrame function. On input i have x and y coords for every frame where to draw point and on the output i want to have video with added points for every frame. Thanks for help.Frame before processing Frame after processing

Upvotes: 1

Views: 490

Answers (1)

PepitoSh
PepitoSh

Reputation: 1836

EDIT: The code below is not suitable solution as the ProcessFrame(ProcessVideoFrameContext context) is part of an interface implementation.

My next solution proposal is to create a custom effect, similar to the GaussianBlusEffect and many more. An example here:

https://github.com/Microsoft/Win2D-Samples/blob/master/ExampleGallery

~~~ Below the original answer for reference.

You can pass in the X and Y parameters and access the pixels of the image.

public void ProcessFrame(ProcessVideoFrameContext context, int X, int Y)
    {

    using (CanvasBitmap inputBitmap = CanvasBitmap.CreateFromDirect3D11Surface(canvasDevice, context.InputFrame.Direct3DSurface))
    using (CanvasRenderTarget renderTarget = CanvasRenderTarget.CreateFromDirect3D11Surface(canvasDevice, context.OutputFrame.Direct3DSurface))
    using (CanvasDrawingSession ds = renderTarget.CreateDrawingSession())
    {

        Color[] Pixels = inputBitmap.GetPixelColors();
        // Manipulate the array using X and Y with the Width parameter of the bitmap

        var gaussianBlurEffect = new GaussianBlurEffect
        {
            Source = inputBitmap,
            BlurAmount = (float)BlurAmount,
            Optimization = EffectOptimization.Speed
        };

        ds.DrawImage(gaussianBlurEffect);
    }
}

More info: https://microsoft.github.io/Win2D/html/M_Microsoft_Graphics_Canvas_CanvasBitmap_GetPixelColors.htm

I did not check if the Color[] is a pointer to the live buffer or a copy. If it is a copy, then you have to write back the buffer with SetPixelColors.

Upvotes: 1

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