AES31
- The Return
Of Universal
Compatibility?

to be a universal solution. With the audio often originating from the video editor, the sound people were on the end of a chain, frequently unsure of precisely what they had received and whether they would be able to open the OMFI data. Many digital audio workstation and dubber manufacturers made agreements to share their format details so that simple audio file interchange was possible and this capability became a selling point. The speed with which the industry accepted Broadcast WAV files helped programme exchange but there were still wider problems. The cries for some form of universal standardisation were becoming unavoidable. Among the many roles that the Audio Engineering Society has cultivated in its 50-odd years of existence, is that of developing technical standards. In 1997, responding to the industry's concerns, it reorganised the relevant standards groups to look more closely at software interchange in professional audio. The result was a four-part standards project, AES31, whose parts were inter-related but would be introduced independently. The first part of the standard, AES31-3, was published in December 1999 and dealt with 'simple file exchange'. At it's heart is a 'super EDL' referred to as an Audio Decision List (ADL). This is a text-based file that can carry edit timing and timecode plus crossfade information to sample accuracy, and run on different computer platforms. It further supports multi channel files in excess of 99 channels, as well as interchange between PAL and NTSC formats. Being a text file it is 'human readable' and, as such, corrupted files can be repaired. DAR's Mike Parker, added that the ADL "contains a list of segment start and stop times, with track numbers and a reference to the WAV file from which the audio is taken, which track it is replayed on, and segment names". The most recent addition is AES31-1, which defines a disk format to 'facilitate audio file transfer and exchange', and was published in May 2001. To quote the standard 'it doesn't describe a complete disk format' but gives enough information to select a proprietary system that will maintain compatibility. The Microsoft-developed FAT32 has been selected as the most practical disk file system. Andrew Bell of Fairlight ESP stated that "FAT32 is the way forward as it offers so many benefits, including compatibility with the majority of operating systems, resistance to corruption and availability of maintenance tools, easy adaptation to meet the needs of high transfer rates, support of long file names and very large capacity disks." Other manufacturers have expressed approval of the use of FAT32 due to the relative simplicity of implementation on any platform, its workability on both PC and Mac-based systems, and equally important, it's robustness.

"Standards groups can only do so much. It's up to the manufacturers to implement it." Cautionary words from Universal Studio's Jay Palmer, and part of his closing comments at the Audio Engineering Society's much anticipated launch event for the AES31 standard. That was fourteen months ago, on the eve of the Los Angeles AES 2000 Convention. The audience had come to witness, in the words of SSL's Mark Yonge. "that not only can we standardise (audio) file interchange but we can show it working". Yonge was chairman of SC-06-01, more fully known as the AES Standards Committee Working Group on Audio File Transfer and Exchange, and this was the first public demonstration of over three years work on AES31. The demonstration was straightforward but convincing. A spoken numerical sequence was recorded onto a Zaxcom Deva portable hard disk recorder. This was then transferred via a Jaz disk to a SADiE workstation where it was edited, before being replayed on a DAR OMR-8 digital editor/dubber, concluding with audio material and edit lists being freely interchanged between the SADiE and DAR systems. It worked. There had never been any doubt about it - all the companies taking part in the demonstration had been championing the cause of audio file interchange for several years and were open to standardisation. It was however indicative of a will to make this work, a new standard which users could point to, and beat recalcitrant equipment manufacturers with. The arrival of digital audio workstations began fifteen years ago, and with them came a host of proprietary formats that gradually replaced decades of near-universal standards in magnetic tape and sprocketed mag film. The accepted ability to move projects easily disappeared. Manufacturers of early digital workstations recognised a need for interchange but with no practical removable media, and the need to divulge proprietary format details to competitors for it to work, little happened. The arrival of non-linear picture editing in the early 90s brought this situation to a head. Suddenly there was a need to move projects to a far greater extent. Audio files and EDLs would arrive from multiple sources and the use of linear copies on tape as a transfer medium was no longer acceptable - shorter schedules didn't allow for up and download of large amounts of audio material. The Avid-developed Open Media Framework (OMF) was introduced as a standard for interchange but in audio terms it was never going

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