Creating XviD video files

XviD is an ideal codec to use for PC playback because it uses the newer, more efficient MPEG4 standard. DivX is the better known MPEG4 codec, but XviD is an open source version of DivX, so its encoder is free and unrestricted.

The drawback with MPEG4 codecs is that it is only supported by a few DVD players so the only place you can watch MPEG4 movies is your PC or notebook computer. But for PC playback, all you need is a media player like Windows Media Player and the appropriate MPEG4 codec installed. Whether it's a DivX or XviD file, the codec for playback is a free download.

The big advantage of using an MPEG4 codec is that files require only a third of the capacity an MPEG2 file for similar results. Another difference is that unlike MPEG2, which generates an .MPG file, MPEG4 in the form of DivX or XviD is wrapped in a standard AVI file format. This allows you to choose any number of audio compression options available, including MP3 and Ogg. One of the best options is the LAME ACM MP3 codec, which you can use with video editing and conversion tools.

The other advantage to using an MPEG4 encoder is that you can also adjust the frame size. DivX/XviD supports any frame size as long as the horizontal pixel resolution is wholly divisible by 4 and the vertical pixel resolution by 2.

The frame size itself has no bearing on the video file size; that's controlled by the video bit rate. However, you do have to balance the frame size with the bit rate. Choose a larger frame size, such as 720 by 576 pixels, and you need a higher bit rate to achieve a given quality level. Choose a smaller frame size such as 352 by 288 pixels and the bit rate can be dropped and file size reduced.

As discussed above, choosing the frame size, bit rate and other settings is a matter of balancing quality and file size. Of course, in effect, you are also restricted by the frame size and other settings of the original video. While you can reduce these settings when converting, you won't achieve much by increasing those settings. For video conversion, the rubbish in, rubbish out rule very much applies.

With this basic information under your belt, you're now ready to get on with the job of converting your videos for PC playback. But first, you'll need to choose a video editing or conversion tool that supports XviD, LAME ACM MP3 codec or any other video and audio codec of your choice. VirtualDub is one of the best video conversion tools available. It can convert from just about any video file format, including VOB files extracted from DVD-Video discs; and best of all, it's free.