Show HN: Merge iTunes and Music App Tracks

Hi HN!

This tool was inspired by the early-2000s tool 'Join Together', which combined iTunes tracks using AppleScript, Quicktime, and an Apple binary for chapterizing MP4 files. As Quicktime and the Apple ChapterTool were deprecated, I created 'Track Concatenator' to fill the gap using FFMPEG and MP4v2.

The main use case is to merge together tracks (usually movements) of classical music into a single file representing the whole work. Chapterizing the MP4 file allows you to easily jump between movements within the same audio file.

I'll have a blog post coming about how I added support for the Music app in Catalina, while still maintaining compatibility with iTunes.