An Ogg page is a unit of data in an Ogg bitstream, usually between 4 kB and 8 kB, with a maximum size of 65,307 bytes. Purpose One of the purposes of multimedia container formats is to allow multiple codecs to be muxed into a single file or stream. For example, to combine audio, video, and subtitles into a single file. The viewpoint held by Christopher Montgomery, creator of the Ogg format, is that the units of muxed codec data should be a separate abstraction layer from the units of data used by the codec in order to limit the amount of buffering necessary when decoding the contained data. In his opinion, which is supported by other developers working with the Xiph.org Foundation, this gives Ogg a technical advantage over alternative bitstream formats such as AVI, QuickTime, and MPEG. Each Ogg page also provides the time offset of the contained data, which allows efficient seeking that is both accurate and compatible with streaming. In contrast, many other formats seek to byte positions in the stream or rely on a table of contents for seeking information. Page structure Every Ogg page begins with the four-byte magic string "OggS". If sync is lost a decoder can look for the next occurrence of this sequence to begin decoding again. These four bytes are followed by a zero byte for Ogg version 0. The version field had originally been intended to allow multiple Ogg page types tuned for different payloads to coexist in the same stream. In the 2000s it became clear that only one page version will be used. The sixth byte of each page specifies type flags. The value 1 specifies that the page contains data of a packet continued from the previous page. The value 2 specifies that this is the first page of the stream, and the value 4 specifies that this is the last page of the stream. These values can be combined with addition or logical OR. The next 8 bytes, or 64 bits, is called the absolute granule position which is a synthetic value that encodes the Decode Timestamp, the Presentation time stamp and distance to first-needed reference. The exact encoding of the granule position is up to a specific codec. The following 4 bytes are the stream serial number to which this page belongs. Each logical stream must have a unique serial number within a physical