Technology Tools for Teaching and Learning

The sort of (lightly compressed) digital video files that result immediately from capturing video tend to be quite large -- on the order of 28.8 million bits per second of video. For that reason, this sort of file is never used as the final format for video on the web. Much smaller file sizes (hence, lower download times for viewers) can be achieved using the video compression schemes associated with either QuickTime, Real, or Windows Media formats. If the video is destined for a DVD, there is a special file format (mpeg-2) that must be used. It has a data rate of 5.7 million bits per second of video; however, since the data is accessed from a (local) DVD rather than via the Internet, this high data rate is acceptable.

There are no major differences in the quality of video files exported to QuickTime, Real, or Windows Media format. Since players and browser plug-ins for all three file formats are widely available, accessibility is not an issue. If you plan to stream the video over the web, one consideration in choice of file format is the type of streaming server available for hosting the video file. (For a discussion of issues related to streaming video, see the page on streaming versus progressive download.)

Since most software applications used for capturing video also allow you to export the video to QuickTime, Real, and/or Windows Media formats, your choice in destination file format may be dictated by the choice of capture software. For example, iMovie (an Apple product) will only export to lightly compressed digital video (in effect "passing through" the digital video as captured unchanged), mpeg-2 (the file format used in making DVDs), and QuickTime (a file format developed by Apple). Similarly, Windows Movie Maker, a Microsoft product, only allows you to export to Windows Media format.