I am trying to use Mpeg1 video files with PowerPoint 2003 and the associated viewer. However, I find they sometimes lock up during playback at about 30 seconds and sometimes advance to the next slide before finishing etc. I have tried both automatic slide transition and timed to the video length, neither seem to work, on automatic when the video freezes on a frame it then progresses to the next slide. If timing is set it freezes on that frame until the time limit is reached. I have found 384x288 Constant bit rate 1150kb/s Mpeg1 work ok, though their resolution is relatively poor as I need to play them full screen. Historically I have only used these for people with NT machines as other sizes will not play, but my preferred format is 800x600 (or 786x576) variable bit rate 2500kb/s (cannot use 2003 viewer with NT so might as well use better quality video). These do not seem to like the 2003 viewer. I doubt it is the MCI as these files play well with PowerPoint 2000 or XP. I haven’t tested it yet, but, previous versions of PowerPoint cannot play AVI files using the Microsoft Mpeg4 v2 codec, I assume this is an MCI issue so will not be different for 2003. Also I do not want to use wmv, 1 they put black bars across the top and bottom forcing an aspect ratio change and 2 this presentation will be distributed to a variety of people and I do not want to force installation of Windows Media Player 9 halfway through a presentation. Ideally I would like a way of getting these Mpegs to play smoothly or any suggestions for another video format/codec that supplies high quality (relatively small file size as these will have to be read off a CD) and playback with 2003 Viewer (without having to install any third party software, therefore it would have to be available for Windows 98SE or above). Any suggestions appreciated. I have tested this on three machines, the slowest a PIII 500 up to a P4 2500, both with 52X CDs, minimum 500MB Ram and also rebuild the presentations on two different WinXP/Office 2003 machines. So far I have not found any video format outside 384x288 CBR 1150kb/s Mpeg1 that will play with the 2003 Viewer?