Video processing on AVMutableVideoComposition

[israelg99]

My goal: I am editing a video using AVMutableVideoComposition and want to use GLSL shader files either with OpenGL or Metal to make nice smooth transitions between clips/assets in my composition.
A simple GLSL transition example: https://gl-transitions.com/editor/directionalwarp?direction=1,1

I know MovieInput works:

movie = try MovieInput(url:movieURL, playAtActualSpeed:true)
filter = Pixellate()
movie --> filter --> renderView
movie.start()

Any ideas how can it be done on AVMutableVideoComposition?
For instance, an arbitrary transition should begin at 2.5 sec mark & end at 2.9 sec mark in the video composition timeline.
More concretely, is there a way to grab a shader file e.g zoom_transition.glsl and apply it to 2.5s-2.9s timeline of the AVMutableVideoComposition.

Let me know if GPUImage is not the place for it, I love the work you guys are doing with shaders @BradLarson .

[Jasper2016]

I have the same question. @BradLarson