Convert 3gp to avi with 3gpToRawAvi converter() site will provide program to go the other way)
Download the 3gpToRawAvi converter from here:
http://www.allaboutsymbian.com/downloads/3gpToRawAvi.zip Unzip 3gpToRawAvi.zip and move folder '3gpToRawAvi' to, for instance, C:\3gpToRawAvi.
Move a .3gp movie file you want to convert to the same folder (C:\3gpToRawAvi).
Then go to the command window:
1. Click on the Start button
2. Click on Run
3. Type in "cmd" and click OK to display the dos window
4. If you're not in C:\> go to C:\> by typing "c:" followed by Enter
5. In C:\> go to C:\3gpToRawAvi> by typing "cd 3gpToRawAvi" followed by Enter
6. In C:\3gpToRawAvi> type "3gptorawavi -o " followed by Enter
Note: Replace with the .3gp file name without the .3pg extension and with the .avi file name of your choice. Eg. "3gptorawavi Video1 -o Video2"
7. The new raw avi file will be placed in the same folder.
Note: A bit of experimentation shows that, on XP anyway, 3gpToRawAvi won't work if it's folder, or any of it's parent folders have a space in the name. For instance if 3gpToRawAvi is in "D:\documents and settings\" or in any folder within "D:\documents and settings\" then you'll get an error when you try to run it.