What Codec does an Audio/Video file use?
Here are some tools to help determine what video file is used by a specific audio or video file:
This shows up as a new tab in the file's properties:
A standalone application:
http://mediainfo.sourceforge.net/en
Another (older) application:
What codecs are currently installed?
For Windows Media Player (WMP):
To install WMP, go to Programs and Features > Turn Windows features on or off > Media Features.
If WMP is in player mode switch to Library mode
Right-click on an empty an empty area of the tool/menu bar
If you don't see the Help menu, then select Organize > Layout > Show menu bar
Select Help->About Windows Media Player
Click Technical Support Information
For the entire system:
http://www.updatexp.com/sherlock-codec-detective.html
The second post here has some good info on media playback:
http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/96acd753-c429-49bc-be54-ba2bce623601
Microsoft FAQ's on codecs
https://support.microsoft.com/en-us/help/15070