The codec is a software designed to compress or decompress an audio file or video. It consists of mathematical formulas that make it possible to reduce the size of a digital audio file and play it to be compressed. There are many alternatives for video codecs such as audio, is a matter of knowing which of them manage to compress without losing picture or sound quality.

The codec is the most popular MP3, but many others have been created with differentiating applications. The AC3 which is usually used in DVDs and OGG, you get better results audio as well as better compression. This can also be found on CD's films. Being a type of coding unlicensed and although this great advantages, it is difficult to find formats and players compatible with it.

Less common are DivX codecs - WMA and Vox Ware Metasound Audio Codec, which are almost obsolete and unused. Del Real Audio Alternative there are several versions, allowing the reproduction of any format linked to RealMedia Player as the RA, RAM, SMI, SMIL, RMVB, among others.