What is a codec?
A codec is a little program which enables you to read movies which have been compressed. Movies are compressed to enable faster internet downloads. Codecs are installed exactly like any other program.

Ok I understand, now what codec do I need for my movie?
The most common codec used is DivX. The latest version can be found here: www.divx.com . The latest DivX version will enable you to read all previous versions.

Extra info: the DivX codec is the most commonly used for .avi movies If you have a .mpeg or .mpg movie, you shouldnt need to install extra codecs. There is a codec very rarely used called Xvid. In case you need it click here to get it

I downloaded and installed codecs, how Yopza can use them?
Yopza can use installed codecs automatically.

DivX codec: get it here
Xvid codec: get it here