[quote=igparker]Hi, I have an 8 minute .mts file from my panasonic camcorder. I want to trim it to just 5 minutes ( last three minutes forgot to turn off camera ). Using the trim function is easy enough. But how can I save this "trimmed file" without having to re-encode it. ie I really just want to replace the original 8 minute .mts file with the trimmed 5 minute .mts file. Thanks Ian. [/quote]
You can not just cut out the last 3 minutes in Powerdirector without Producing the trimmed video.

You can produce to the same or better format, you will not lose quality that you can see in the video, it you use the correct profile. I recommend AVCHD 1920x1080. That produces a m2ts video which is the same format your Panasonic camera uses.

There are programs on the internet that can just shorten the video without any re-coding.

Thanks