Theora is a free and open video compression format from the Xiph.Org Foundation. Like all our multimedia technology, it can be used to distribute movies and video online and on-disc without the licensing and royalty fees or any other vendor lock-ins associated with many other video formats. It is available at http://www.theora.org.
To avoid confusion, we will introduce some nomenclature. By bitstream, we assume some sequence of bytes. Logical bitstream is some representation of video or audio data. Codec, or COder-DECoder, is a set of functions that encodes and decodes logical bitstreams into a set of compact representations named packed bitstreams. Since usual multimedia data consists of multiple logical bitstreams, the compact representation must be split into small chunks, which are called packets. Each packet has a specific size, a timestamp and a checksum associated with it to guarantee the packet integrity. The scheme for bitstreams and packets is shown in the following image...