In response to this post I was wondering if anyone would find a command in their context menu (or perhaps an entry in 'Send-To') when they right click on a folder which renames any MP4 file found to M4a (recursively?) useful.

Hmmm.....
Ok, got it now: Put Case's Sweep in "System32"
(Or "System" on 9x or just any %path%, just edit the following accordingly...)
Make a "m4ren.bat" file (with e.g. notepad) with following content and put it same place:

Then make a "m4ren.reg" file (with e.g. notepad) with following content anywhere:

And doubleclick it, answer yes.

EDIT: Everything. Stupid me!
EDIT2: New link to Sweep on Upload Forum

Mr_Rabid_Teddybear,
Would you rather use a built in function then a 3rd party program?

It can be done with just batch file.
Or if somebody wanted to be elaborate, one of the native scripting languages could be used.

(Nice work though, btw. The less that needs to be done. )

tec

how about rename 's/.mp4/.m4a/' *mp4 ?

Indeed.. plus the right tools are free