AVI format was introduced by Micosoft in 1992 and it is 18 years old now. But it is still very widely used on various Windows applications, online and on some digital gadgets such as Zune, Creative Zen and some major digital camcorders. AVI is shortfor some features found in newer file format containers such as MPEG or MP4, but is still widely used by consumers and even supported by some standalone DVD players.
AVI stands for Audio Video Interleave. You may think that AVI is a video format that has everything including most video and audio specs are pre-defined, however, AVI is actually a multimedia container format that allows synchronous audio-with-video playback, a package that contains both video and audio, but you don’t actually know what’s inside. Therefore, AVI files from different sources may have different contents inside.
Your computer can probably play most AVIs without any additional software needed and meanwhile refuses to play some AVIs. This is simply due the fact that those AVIs have been compressed using a different codec and your computer has a codec installed already for the ones that work — and you need to install a new codec to open the one that refuses to play.
If you want to play an AVI file, you need two things: a video player software and a codec. Each version of Windows has a version of Windows Media Player, therefore, the software part doesn’t pose any problem. The issue is with the codec. AVI and codec are inseparable. As stated above, AVI is simply a file format that doesn’t itself define how the video inside the file was made and how it should be opened. The video inside the AVI is typically a compressed video stream that is made with a special tool, called as encoder. And Codec is an abbreviation of Encoder and Decoder. It plugs into your computer’s operating system and allows the software installed on your computer to perform the decoding for the video that has been encoded with the codec you installed. So, to successfully play all AVI files, you need to right codec. If there are AVI files you cannot play, you can turn to a video converter that can convert AVI to more compatible file formats for playback on your computer.