Video coding

Video data usually not only contains visual information but also audio. Therefore, it is often referred to as multimedia. Modern video coding standards even include other multimedia data such as synthetic computer graphics, text and meta information for searching/browsing and digital rights management. They also often provide mechanisms for user interaction.

However, the most intensive parts of video data in terms of data size (memory demand, transmission bandwidth) remain (visual) video and audio data. These parts have to be compressed. Unfortunately, this can hardly be done without loss of quality (lossy compression). There are two special research areas that deal with multimedia compression: video compression and audio compression.

Video coding has two distinct goals: storing and transmission of video data. These two goals have much in common. Therefore, video file formats usually have the same structure as streaming video formats with just a little header information added.

A computer program the encodes and decodes video data is called video codec. (The part that only deals with audio data is called audio codec.)

Almost all successful techniques developed for video coding have been integrated in the MPEG standards. Therefore, the MPEG standards represent a comprehensive knowledge base for video coding. Most video coding standards and commercial formats are modifications of MPEG.