The Problems with macOS and AVCHD / MTS
Mac OSX does not handle the AVCHD format or it’s internal MTS files very well, when it handles them at all.
October 2020
What is AVCHD?
It’s hard to find good information on the AVCHD format and how it works. Here is what we know.
Converting MTS Files Losslessly to MP4 on macOS
If you aren’t afraid to use the Terminal, you can easily convert your MTS files into MP4s.