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~ RIFF WAVE Files and Chunks ~
The Microsoft RIFF file format definition defines a series of chunks into which the contents of the file are subdivided. Each chunk has a four character identifier. In the case of a WAVE audio file the principle chunks involved are the " fmt" (format) and "data" chunks. These two chunks contain all the information required to replay a linear PCM wave audio file. Non-linear file formats also have a "fact" chunk containing information about the coding system.
In addition to these operational RIFF chunks the format also defines a series of "LIST" subchunks containing text information describing the audio file and a "DISP" (display title) chunk which can be used by a replay application to display a more meaningful title than just the filename. The "DISP" title may also include a graphics file.
In 1999 the European Broadcasting Union defined the Broadcast Wave File with additional "bext" and "mext" chunks holding specific information of interest to broadcasters.
Around the same time the commercial radio industry began development of an open standard for interchange of Radio Traffic data between systems. This was ratified in 2002 by the AES and published as standard AES46-2002 which defines a new RIFF chunk, the "cart" chunk.
Our broadcast audio applications use some of the original WAVE standard "LIST" subchunks to hold information such as producer, program name, date and time and cue/script material, which may be useful to users of the broadcast material.