What is a video codec

A codec is software to encode/decode video or audio. Codecs are downloaded together with video programs or in codec packs. Most video players typically install a number of common codecs with the actual player programs.

In windows codecs are normally distributed as dll files which implement codecs as direct show filters. Direct show filters are registered in the windows registry for a given fourcc code. There are a number of programs to determine what codecs are installed on a computer and which are active for a given format.

Since codecs are code they can cause issues with the software that uses them, a bug in a codec can cause the program using the codec to crash, hang or cause memory leaks. Prefer to use common and well tested codecs, if a video player crashes for a specific video file try to restart the video file to see if the problem was related to incompatibility between the running codec and other codecs that has run before. If the issue persists it might be a good idea to try to play the file with another codec that supports the same file format.

Links

Download Fast Video Indexer from its homepage
Download gspot to detect the codecs you have installed