Hmm, here to report this was working flawlessly for me on Xcode 14.3, probably couple dozen times, until just now it stopped working all of a sudden.

Another mystery is that for video frame CMSampleBuffers, they are always returning outputDuration as kCMTimeInvalid. Even in the Apple sample app AVMultiCam this is the case. So I can't calculate the trim values from the duration. The documentation says this should only return 'invalid' if there is an error, but I have no idea how to check for this error.

Yes this is currently/still broken for me on all my builds