as i told you, I have changed a .WMV file to .AVI file just by changing manually the extension, not coding it from one format to another and it woks perfectly. Actually what I really call coding and decoding, to be able to reproduce a video is to have the codec which could be in one of this formats*: CVID Cinepak video format I263 Intel 263 format. IV50 Intel Indeo V5 format MP42 Microsoft MPEG-4 format MP43 Microsoft MPEG-4 format Version 3 DIV3 DivX DIV4 DIvX Xvid Divx-by a opensource group->xvid MWV1 Aware Inc.'s Motion Wavelets Video Codec. more...? *(notice how weird it is that an AVI "format" can have any of the aboves "formats") For me what it means is that "inside" avi or wmv or mov there´s different formats and that is what matters to the player, the codec they use, not the extension (even though they dont have license for all extension, and sometimes the players don´t accept them, thats why I change em manually). Thats why I call video extensions "nutshells" instead of formats. Cause is the way I understand and explain this weird video encoding thing. That is (i think) why I can change manually a WMV to AVI and still works... because it was indeed a MP43 format and I have the codec. So... a Divx is a video format inside of a AVI video "format" I think. Anyway... confusing.