These are the only parts of the standard that have been published so far but following the pragmatic approach adopted by those working groups, the likely form of the remaining parts is well known. AES31-2 suggests that audio data is to be held as multiple mono Broadcast WAV files (BWF) that are compatible with all PC and Mac WAV applications. BWF is an EBU -developed standard built on the existing WAV file format and is widely accepted. The final section of the standard is AES31-4:Object Oriented Project Interchange and current thinking appears to be considering some combination of OMF and the Advanced Authoring Format (AAF). However these are proprietary formats and part of what some parties see as competing interchange formats. For this and other reasons is likely that this final part of the AES31 standard may take some time to be ratified. The necessary scope of a sophisticated yet practical level of interchange is still under discussion. Attitudes vary about the needs to move the higher levels of signal processing and automation with a project when they may have no relevance to the new situation. To an outside it may appear that all these 'difficult' decisions have been left to last, enabling swifter agreement on the more important other parts of the standard. With the bulk of the standard in place, a number of manufacturers have been swift to implement AES31, at least in part. SADiE and DAR have already done that, and around ten other major companies have announced 'AES3 1 support with the intention of implementation'. So far there seems to have been little response from the video workstation suppliers but that may be largely dependent upon the attitude of Avid who have so far been publicly quoted as not understanding the need for AES3 1 while there is OMFI. So that is AES31. If it was fully implemented by every equipment manufacture we'd be close to the universal compatibility the audio industry once knew. It could also introduce facilities for new levels of information exchange - faster network transfers, direct compatibility with the Internet, and be usable for realtime recording and digital archiving. But perhaps more importantly it would save both precious time and money in post production. For the manufacturers, AES31 will be relatively simple to implement. Users benefit from an open standard belonging neither to any one manufacturer nor any trade association. A major obstacle to efficient audio post production may be about to be removed.

KEITH SPENCER-ALLEN

Full specifications of published parts of AES31 may be found and downloaded via the AES website - www.aes.org.