.mp4 Movie to .mp4 Apple Audio Music.app Problem

[galaherm]

It seems whether splitting on Markers and saving as mp4 Apple Audio or using a using a Batch Processor, the resulting files sometimes are silent in MacOS Ventura Music.app and also when they do play the AirPlay icon in Music.app is missing. If the sound still plays the control for the volume of different devices using AirPlay are not available. For example a song from an imported CD will play fine and if the next song was saved using Amadeus Pro from mp4 Movie to mp4 Apple Audio ACC the AirPlay icon will disappear. I've tried resaving these into mp3 and then back to mp4 audio and the problem goes away but I'd rather not have to have this convoluted process. I'm wondering if some 'movie' elements are not being removed. Any advice or insights would be appreaciated.

[Martin Hairer]

Are you sure you don't actually want .m4a files rather than .mp4 audio files?