Adding information to audio files

CEDAR Cambridge metadata creator and editor

The CEDAR Cambridge BEXT Metadata generator and editor allows you to create and/or modify existing metadata associated with audio files. We have also made the Process Manager transparent to existing metadata, both in the BEXT chunk and other chunks, which will pass through the system unharmed if you wish them to do so.

Understanding metada

Metadata has been described as 'information about information', and that is a good way to view audio metadata; it tells you things that you may wish to know about the information contained within the raw audio data. These things may be as diverse as the name of a track, how or when it was recorded, by whom, the mean level of the audio, whether the sound suffers from unwanted degradations, and so on.

Many audio file formats exist, and most of these contain metadata in addition to the raw audio data. One of the most important of these is the Broadcast Wave Format file (often referred to as a BWF or BWAV) which was developed to facilitate the exchange of audio between different broadcast environments and equipment based on different platforms. As well as the raw audio, a BWF contains the minimum additional metadata that is considered necessary for this, and does so by adding a Broadcast Audio Extension chunk of data to the basic Microsoft Wave (.WAV) audio file format.

The information in the BEXT chunk contains some fields designed for reading and modifying by humans, and some that are used primarily by the devices that need to use the data. If the audio file contains additional chunks, these may be ignored, or may be stripped when CEDAR Cambridge processes and saves the audio. It is important that these are handled correctly or important information may be lost.