matthiass4804684 wrote:
The AVCHD file that comes from the Panasonic TM900 is .mts. Panasonic recommends to use the enclosed tool "Panasonic HD Writer" for copying to PC, which writes a .m2ts file.
I have the same camera except for a model number change so that it could be kitted with a 3D lens. I used HD Writer a lot at first as a preliminary step to using Premier Elements, then in Version 9. Version 9 didn't like 1920x1080p60 files much, so HDWriter helped with some "work arounds".
The m2ts files and the mts files are exactly the same except for the file extension. You can change it manually back and forth if you want. HDWriter imports some small companion files created in the camera with matching primary names to the M2ts. HDWriter uses the set of matched files to do some unique editing tricks. It uses the m2ts as a signal to suggest the companion files are there. Among other things it can trim, split and join clips losslessly, or without "rendering". It can put clips back on the camera so that the camera can be used as a media player with the included remote. It can join the pieces made on the SD card caused by the file size limits. It has to have all four files in the set to do those things. HDWriter is terrible at everything else from color correction and transitions to titles. Unless you need the few unique features of HDWriter it wastes time and disk space. Use of any other software to move mts files to your computer, especially if you use a program like Premier Elements for your video editing. The little accessory files are useless to everything other than HD Writer.
There is no reason you should expect mts or mt2s files to behave differently in Organizer.