WMV is short for Windows Media Video; it is a versatile container format and also a video codec which was developed by Microsoft.  The container supports features such as chapters and subtitles and can contain different video codecs.

What are codecs and container formats?  By the time you’ve finished reading this you should know a little more about them.  Most persons have heard terms used in video before like MPEG, DIVX, and AVI but although the terms are used most persons don’t understand what they mean.

Whenever people discuss watching video on their computers you will almost always hear one of the above formats mentioned and sometimes you will hear people complaining that they got a video that won’t play or that they played the file and only got sound and no video, which usually happens because they don’t have the proper codecs installed. So how is all this related?  Let’s get into it.

In video a container format is just that, a container.  Depending on the container used there will or will not be support for subtitles and multiple audio and video tracks.  Now the player that is used on a computer determines whether or not the container can be opened;  MKV for example, is another container format which supports multiple audio, video and subtitle tracks and cannot be played on earlier versions of Windows Media Player.  Later versions of Windows Media Player can play MKV files but cannot take advantage of all its features.

In video a codec is used to Encode/Decode video.  Some formats are readily supported by Windows and WMV is one of those that are supported; mainly because it was developed by Microsoft which obviously is also responsible for making your operating system.

Now container formats like WMV for example, can support different types of video streams; if a Video is encoded or created using DIVX and then placed in the WMV container it will work perfectly but if it is played back on a machine that doesn’t have DIVX installed, then there will be no video.

AUDIO STREAMS can also be placed into a container format and an example of this would be a music file or MP3.  If you try to play a WMV file that is encoded with DIVX video and MP3 audio without DIVX installed then the file would play audio only; this is because Windows plays MP3 by itself but DIVX needs either codecs or filters to be able to play back the video.

Though there are many different container formats and video and audio streams, WMV is one of the more popular for both a container and a video stream while WMA (Windows Media Audio) is one of the more popular for audio formats.  One of the benefits of using these formats from Microsoft is the DRM (Digital Rights Management) capabilities.  This is the ability to encrypt or copy-protect your audio/video files so that they cannot be played back on any PC except yours – a deterrent for video/music thieves.