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410 15. Using Multimedia in VR
15.5.2 Image Processing with an In-Place Filter
One application of an in-place filter that comes to mind is video overlay. For
example, you might want to mix some real-time 3D elements into a video
data stream. Other possibilities might be something as trivial as producing a
negative image or, indeed, any image-processing operation on a video stream.
The key to processing an image in an in-place filter is to get access to the pixel
data in each frame. This requires reading it from the upstream filter, changing
it and sending it on to the downstream filter. We won’t give full details here
but instead outline a suitable ...