I have searched this and a few other forums for an explination. Here is my question, why does my moment play some AVI files, and not others? It also will not play MP4 files. I have apps that say it will play MP4 files, but no luck with those apps, or the default player. I need some help please. It will play 3gp files, but the quality is woeful. Yet I put one movie on there that says AVI, it works like a charm! My son's EVO won't even play it, but I can! Put another AVI on there and nothing! What gives?