How to convert separate .MTS files to .MP4? (or other iTunes compatible)

[RTF]

As a recent Windows to Mac switcher I would like to gain more pleasure from my Apple eco system at home.

Therefore I would like to convert a lot of home video files I have on my mac to an iTunes compatibel format.

Most of the files are filmed with a JVC handy cam and are in .mts format.
I've been lazy and just dumped the .mts files on my NAS. Those are playable on my PS3 en windows PC.

But now I have iMovie and iTunes I Would like to have the files via iMove into iTunes as a couple of movies (instead of hundreds of files).

But iMovie doesn't recognize the .mts format. With apps like iFlicks and iVi I tried to convert the files but I get errors (something with unsupported by 64bit iTunes).

Handbrake does the trick. But with Handbrake I don't know how I can drag 50 files at once to convert?
I als got the feeling that handbrake downgrades the quality of the file.

[TLDR]
I'm talking about hundreds of separate .mts files located on my NAS.
How can I get them in iMovie?

 

[Dave Braine]

I've used RewrapAVCHD:
https://www.macupdate.com/app/mac/39800/rewrapavchd

You'll also need Perian:
http://perian.org/

Scroll down the page for the download.

 

[stephanno]

Audials is the solution you need. Audials simply converts any and every file in the highest possible quality. Audials lets you conveniently convert any file and then use these freshly converted files on your portable devices.

http://audials.com/en/converter_how_to/start/start.html

 

[ChrisA]

This works well. It is reanably fast and there is no loss in quality
http://www.divergentmedia.com/clipwrap

Place the SD card in the computer, open the folder and drag the files into Clipwrap and they are converted as they are read off the card so no extra time is wasted by first copying off the card to the desktop and then re-wrapping. Do it in one step. You can tell Clipwrape where to place the converted files so the data just moves once.