AMPS MEETING REPORT 30/11/97

ADSG DIGITAL DUBBER

Keith Spencer Allen

This AMPS meeting at Twickenham Studios followed the theme set by the Deva meeting a few weeks earlier. As with that meeting, the subject was a first UK showing of important new digital technology and again AMPS opened the meeting to members of the Institute of Broadcast Sound and the BKSTS. The combination was a full house to hear more about this new digital dubber from ADSG, and equally important, the development of a 'new' media upon which it is based, presented by a five strong ADSG team. ADSG are the Advanced Digital Systems Group, a research and development section within Sony Pictures, Los Angeles. Just over three years ago the post production division of Sony Pictures identified the need for a digital replacement for their mag film dubbers as part of a move to a totally digital signal chain. According to Michael Kohut, President of Sony Post Production Facilities, their digital vision saw different requirements for different types of work - "We consider that TV post will be 16 or 20-bit, and for feature films we want nothing less than 24-bit uncompressed audio. It was essential that whatever system we developed would have switchable word length." ADSG identified Iomega's Jaz drives as a possible record medium but were aware that they weren't designed for the intensity of professional A/V type use.

They started a development programme with Iomega to create a more suitable version of the Jaz format. A number of improvements were identified and some firmware written that tells the drive how to operate - what parameters it needs to meet consistently over a long period of time. Mechanical upgrades were included and most importantly, all drives and disks are fully tested for 24 hours, over continuous read and write cycles before they become A/V Certified Media. These certified versions retain full compatibility with standard Jaz media but only the use of certified drive and media together offer the advantages of the firmware control and reliability. The ADSG dubber is based around the use of dual A/V certified Jaz drives. Running with two 2GB media this offers a maximum of 28 minutes of 16-track recording at 24-bit/48kHz, which increases to 42 minutes when the bit rate is dropped to 16-bit. Using the the 1GB media halves these times. The standard unit comes with AES/EBU inputs and no analogue connections although converter sets will be available in the future. It is envisaged that this machine will interface with a digital signal chain and will therefore allow 16-, 20- and 24-bit rates with 44.056, 44.1, 47.952, and 48kHz sampling rates with future 96kHz capability. A choice of audio formats for the Jaz drive is intended to be supported including PCM, Deva, Digidesign ProTools SDII, OMFI, WaveFrame, Sonic Solutions and Broadcast .wav to allow easy interchange of programme. Audio can be played out in forward or reverse and up to 1.5 times speed.

While each dubber can run as a standalone unit it is also possible to run large numbers of them under software control from a external PC. This allows some of the simple internal cut and paste editing functions to be applied across any or all of the machines running as part of a network. Production was due to start at the beginning of this year, initially to fulfil Sony Pictures' own needs, and with wider supply following that. It is perhaps in the practicalities of operation that the advantages of the A/V Certified Jaz media will be popular. Sony Pictures plan to standardise on it for virtually all post production components - audio, pictures and graphics. A single Jaz is roughly equivalent to a 2000 foot reel of full coat mag film but considerable smaller with considerable savings in volume and shipping - they plan to distribute foreign audio masters on Jaz for these reasons. Copying is quick - around six minutes for a full 2GB Jaz clone running at 6x speed. Following the detailed demonstration of the dubber and explanation of the media, the meeting was thrown open to a question and answer session. Questions were equally spread between the dubber and media. At the time of the meeting, ADSG were vague about costs and distribution, not being a manufacturer they were having to learn about this aspect of the business, but we were assured of realistic pricing on both items.

Our thanks to Gerry Humphrey's and Twickenham Studios for arranging hosting a very successful meeting.