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AES31 is a standard developed by the Audio Engineering Society for the interchange of digital audio projects between different systems. The primary purpose of the standard is to allow exchange of audio editing projects between digital audio workstations (DAWs). The standard is divided into three parts, the highlight of which is the project interchange format, which defines a standard for edit decision lists.
- Part 1 - Disk format
- Ensures the ability to read files across platforms.
- Part 2 - File format
- Specifies use of monaural Broadcast Wave Format files
- Part 3 - Project interchange
- Provides a method of exchanging edit data in a text format. This allows an audio edit in one DAW to be opened in another, with little or no difference in the mix. The standard focuses on simple and accurate parsing, and human readability.
The standard describes a 'time-code character format' (TCF), which is used to express time code information in character notation. It enables a sample-accurate time to be specified within a 24-hour period.
The format is defined as HHiMMiSSiFFissss, which is composed of hours (HH), minutes (MM), seconds (SS), frames (FF) and samples (ssss), separated by indicators (i). The character used for each indicator signifies the frame count/time base, film framing, video field/time code type, and sample rate, respectfully.
The project interchange standard uses plain text files with a custom markup language called 'edit decision markup language' (EDML). A file is divided into sections using XML-style tags, each of which can contain different keywords which are surrounded by parenthesis. An example of the language can be seen below:
<VERSION> (ADL_ID) "" (ADL_UID) e5135ed0-5bc7-4087-8674-5a97cf4534e2 (VER_ADL_VERSION) 01.01.00 (VER_CREATOR) "SADiE" (VER_CRTR) 05.06.02 </VERSION>
- AES31-1-2001 (r2006) 'AES standard for network and file transfer of audio - Audio-file transfer and exchange Part 1: Disk format' by the Audio Engineering Society. Published 2001, Reaffirmed 2006.
- AES31-2-2006 'AES standard on network and file transfer of audio – Audio-file transfer and exchange – File format for transferring digital audio data between systems of different type and manufacture' by the Audio Engineering Society. Published 2006.
- AES31-3-2008 'AES standard for network and file transfer of audio - Audio-file transfer and exchange - Part 3: Simple project interchange' by the Audio Engineering Society. Published 1999, Reaffirmed 2008.
- "The AES31 Standard". Retrieved 2013-06-02.
- Mel Lambert (October 2001). "AES31 - Eliminating the File Exchange Conundrum". Mix.
- David Miles Huber; Robert E. Runstein (2012). Modern Recording Techniques. CRC Press. p. 273. ISBN 9781136117732.