What format does a movie have to be in to play on a DS ?

[dUnKle]

and how do I convert an AVI file to it ?

 

[RandomLee]

They have to be in .DPG format.

Here's a couple of guides on how to convert videos:

http://m3wiki.com/index.php/Yee_and_Firon's_(Guide)_Videos_on_Moonshell_with_BatchDPG_Guide

http://www.themanfromdelmonte.co.uk/nintendo-ds/nintendo-ds-moonshell-dpg.htm

I havent tried myself as I can already watch DIVX videos on my mobile.

Seems easy enough though

 

[Dan81]

....use SUPER. its freeware and will convert for DS, Mobiles, PSP, PS3 etc etc. just do a google for it.