Maybe you can try to use Leawo MTS Converter.
Leawo MTS/M2TS Converter lets you convert MTS and M2TS videos to
various formats, e.g. AVI, MP4, WMV, MOV, MPG, FLV, and RMVB, to meet
different demands of edit, playback and application. This powerful
MTS/M2TS video converter supports videos recorded by Sony Hard Drive
Camcorders and other recording equipments. It supports up to 1080p video
resolution with synchronization of audio and video upon any format
output.
You can free download it in here:
http://www.leawo.com/mts-converter/