As a DV photographer, I purchased Sony HDR-AX2000 which creates MTS files that can’t be read directly by FCP. But I am lack of skilled computer program instructions. It couldn’t seem to pick a correct encodings to get the audio and video to stay in sync. I try imelfin video converter which can convert MTS Files to Editable Quicktime MOV.
https://www.imelfin.com/doc/how-to-convert-mts-files-to-editable-quicktime-mov.html.pdf