I have a great deal of movie backups in from avi, xvid for SD video and some h264 with AAC sound for HD. SD files are all various resolutions, none over 720x480 (DVD) moderate bitrates (1500 Kbits max. I think). My N900 plays them no problem. Just copy and paste o.O for the HD part, I am using format factory (free) to recompress to .mp4, resize from 1920:1080 to the screen resolution of 800:480. bitrate usually down to 2000Kbits. I am talking stock N900 here.