Researching file formats 23: Audio Definition Model

This blog post is part of a series on file formats research. See this introduction post for more information.

Update: The official format definition is now online here: Audio Definition Model. Comments welcome directly to the Library of Congress.

This format is about audio, but it’s a text-based document that describes audio. You can say it defines an audio model. It is typically stored as XML, but JSON is a valid option, too. While the rest of the software engineering field goes “ick” when it hears about XML, both the cultural heritage sector and audio/video media engineering sector still use it heavily.

ADM is coming out of research from the European Broadcasting Union, which have other hits like EBUCore for describing media elements. The idea behind ADM is to standardize how audio is stored, inspired by the rise of extra high-def sounds (like, going beyond Dolby 5.1). Where does it go, physically? Or are there different language tracks? If so, what are the order? Stereo and/or mono, or something else?

Formally, “Audio for broadcasting and cinema is evolving towards an immersive and interactive experience, which requires the use of more flexible audio formats. A fixed channel-based approach is not sufficient to encompass these developments and so combinations of channel, object and scene-based formats are being developed” (source)

BBC R&D seems like they are quite invested in this format, making a toolkit for ADM usage.

If interested in more, here are some of the resources to check out:

• International Telecommunication Union. “BS.2076 : Audio Definition Model”
• BS.2076 : Audio Definition Model”: Recommendation BS.2076-2 (10/2019). This is a direct link to the English PDF of the latest standard.
• European Broadcasting Union (EBU) ADM elements reference