Example of how to mimic the iOS equivalent of AVAssetWriterInput and CISourceOverCompositing

[darrinps]

In iOS, one can take a sample buffer, modify it with CISourceOverCompositing and then use the result to feed AVAssetWriterInput.

That allows them to easily do things like add overlays to video. Since such functionality still does not exist in the MediaRecorder, an example of how to do this with what exists today would be very beneficial (just do a Google search on Android Video Watermark/Overlay/etc....it's a commonly requested topic with no good answers).