Ryken.Video.Effects

A .NET UWP library to make it a little easier for you to render videos with Win2D effects.

Using this component

All code below this point assumes you've imported the Ryken.Video.Effects namespace.

Step 1: Register your MediaPlayer/MediaElement

First you need to register your video playback method to receive effects, whether it be MediaPlayer, MediaElement or MediaClip. You do this by calling either:

VideoEffectManager.AddVideoEffect(MediaElement mediaClip, string id, IPropertySet properties)

VideoEffectManager.AddVideoEffect(MediaClip mediaClip, string id, IPropertySet properties)

VideoEffectManager.AddVideoEffect(MediaPlayer mediaPlayer, string id, IPropertySet properties)

VideoEffectManager.AddFrameServerVideoEffect(MediaPlayer mediaPlayer, string id, IPropertySet properties, FrameworkElement container)

The parameter id can be whatever string you want, and any effects that are registered with this same id will be used to render your video (we'll get to this later).

Using VideoEffectManager.AddFrameServerVideoEffect puts the MediaPlayer into frame server mode, and renders it on top of the provided container element. This mode may be useful to some, as the resolution of the video surface will be in screen resolution rather than video resolution, which allows for custom upscaling scenarios.

Step 2: Register an effect

Next, you register an effect using:

AddVideoHandler.RegisterVideoEffectHandler(string id, IVideoEffectHandler handler)

The parameter id must be the same used to register your playback method in the previous step. handler is the object that will render the video using effects. You can either implement IVideoEffectHandler yourself to get the effects you want, or you can use one of the handlers than come in the library such as SaturationEffectHandler.

That's it! Just call VideoEffectManager.AddVideoEffect/AddFrameServerVideoEffect and AddVideoHandler.RegisterVideoEffectHandler you're good to go!

Examples

Render a video in black and white

This small example shows how to render a video in black and white using SaturationEffectHandler with the Saturation property set to 0. This example assumes you've already created a MediaPlayer, MediaElement or MediaClip.

// First set your MediaPlayer up to receive effects. This can also be a MediaElement or MediaClip.
VideoEffectManager.AddVideoEffect(mediaPlayer, "Any old string works as an id", null);

// Create the saturation effect and set saturation to zero
var saturationEffect = new SaturationEffectHandler() { Saturation = 0 };

// Register the saturation effect with the same id string you used in .AddVideoEffect.
VideoEffectManager.RegisterVideoEffectHandler("Any old string works as an id", saturationEffect);

Now your video is in black and white!

Implementing IVideoEffectHandler

If you want to create your own effect, you'll have to implement IVideoEffectHandler. IVideoEffectHandler has three methods, ProcessFrame, CreateResources and Destroy resources.

ProcessFrame(IVideoEffectHandlerArgs args) is where you draw the video frames. It receives arguments that make it easy to start drawing with Win2D. This will be called automatically for each frame by VideoEffectManager.

CreateResources() is where you create the resources you'll need in ProcessFrame. You probably won't have to implement this method.

DestroyResources() is where you destroy the resources made in CreateResources, if any.

To render a video frame in ProcessFrame(IVideoEffectHandlerArgs args), you use Win2D to draw args.InputFrame onto args.OutputFrame, by creating a CanvasDrawingSession on args.OutputFrame. While this won't serve as a tutorial for Win2D, the example code below will show you how to implement ProcessFrame to render a video with a gaussian blur effect:

void IVideoEffectHandler.ProcessFrame(IVideoEffectHandlerArgs args)
{
    using (var drawingSession = args.OutputFrame.CreateDrawingSession())
    {
        using (var blur = new GaussianBlurEffect() { Source = args.InputFrame, BlurAmount = 25 })
        {
            drawingSession.DrawImage(blur, args.OutputFrame.Bounds, args.InputFrame.Bounds);
        }
    }
}