Xing header
The Xing header ( Xing header data area ) is a data structure within MP3 files with a variable data rate .
In the MP3 format designed for streaming media applications, the audio signal is divided into consecutive frames that are largely encoded independently of one another. There is no header data area provided in the file-wide information such as the total length of the file or the number of frames are stored. On the one hand, this makes it possible to decode fragments of files without any problems. In the case of files with a variable data rate, in which the individual frames are different in size, however, an MP3 player has no way of determining the total playing time or of jumping to a certain (temporal) position without reading the entire file.
To solve this problem, the MP3 encoder can provide additional information with the Xing header data. This is a special frame at the beginning of the file, which instead of audio data contains a table of contents consisting of 100 jump positions as well as information on the file size and number of frames.
The Xing header data area was originally introduced by the Xing MP3 encoder from Xing Technology , but is also supported by other programs such as the LAME encoder.