Help      |      Chebucto Home      |      News      |      Contact Us     

97. Codecs key to playing media files

By Andrew D. Wright

Your friend gives you a CD with video on it from his vacation. You pop it into your computer, double click on the file name and when it opens up you can hear the sound but there's no picture.

That's funny, you've played movie files with a .AVI file type before and they've worked fine. What's going wrong is you don't have the right video codec.

A codec is a way to COmpress and DECompress or COde and DECode information, in this case the video information in the .AVI file.

The .AVI video file format is not one kind of file, it's what is called a container format. It's a way of holding data in a form many different programs and platforms can understand. That data, the video and sound portions of the movie, can be encoded using any one of several different codecs. The player must have the same codec or a compatible one to be able to properly play the file.

DivX is the best known video codec. It's a proprietary format that offers excellent picture quality with a greatly reduced file size. In wide usage since 1998, these days many set-top DVD players can play DivX files, which can have a .AVI or .DIVX filename.

Xvid is an Open Source video codec in wide usage. It's the main competition to DivX (try spelling Xvid backwards) and like DivX is a variation on the MPEG-4 Part 2 standard for encoding video. Because of possible patent issues in the U.S. and Japan, the Xvid codec pre-compiled for Windows is not available from the Xvid site directly but there is a link to one made by a third party.

The combination of the right codec and right media player can add many features to a video file such as subtitles, menus, and support for advanced audio configuration items like 5.1 surround sound and multiple languages. The quality of the picture and sound during playback can be dramatically improved as well.

There are many media player programs available for download but for Windows users it is hard to beat Media Player Classic. An Open Source media player modelled after Microsoft's early Media Player 6.4, Media Player Classic offers simplicity of use through its familiar interface combined with a powerful feature set accessible through menus.

When combined with ffdshow, a popular encoder/decoder program, there are few file formats Media Player Classic won't play. ffdshow adds support for advanced video and audio processing during recording and playback for improved picture and sound quality as well as support for a number of different audio and video codecs.

While still in very wide use, the .AVI container file format is starting to be replaced by others offering more features and smaller file sizes. Videos can be .MP4 files, .OGG files, .MKV files and .3GP files among other more widely known container file formats such as Apple Quicktime's .MOV file type or a DVD's .VOB files.

Media Player Classic (free):

ffdshow (free):

Xvid (free):

DivX (free and shareware):

The Mousepad runs every two weeks. It's a service of Chebucto Community Net, a community-owned Internet provider. If you have a question about computing, email or click here. If we use your question in a column, we'll send you a free mousepad.


The Mousepad Index


Originally published 3 December 2006


Our community is online here!


A feature of the Halifax Herald