I didn't find any way to get my old 200 m2t filenames changed to format yyyymmdd_hhmmss.m2t, the date being the one when filmed (if I just get a text file of all dates I can myself create a renamin script etc). In e.g. super I can see the date one by one. I tried hdvsplit to split the files and create new files with date as name, this worked, but some files were split which I don't want. Sony PMB shows the dates but I cannot export them to text file in any way.

Hi

Go look at Advanced Renamer - Fast and feature rich batch rename utility (http://www.advancedrenamer.com/)

I have used it to relabel photo files in the format you want using their XCIF data.

I haven't used it for video files but it is worth a quick look.

Cheers, Ian

Thanks for the hint on Advanced Renamer, it works nicely. But it don't support extracting date-info (shooting date etc) from videofiles.
However, I found a workaround. Sony PMB had created an extra .modd file for every clip. This included a real number for the date taken. Excel could change this to human readable form. From this I created a script that did the job.