By utilizing the DP571 Dolby E encoder, postproduction houses may record eight channels of audio, with associated metadata, via a single AES-3 pair onto the digital video storage medium of their choice. Key to the system is the matching of audio and video frames, allowing trouble-free editing, and its compatibility with all international video standards. According to Dolby, the format is robust enough to withstand 10 or more encode/decode cycles without degrading the consumer’s audio experience.
Supplementary units provide tools for tighter integration of Dolby E, such as the DP579 tri-level sync interface, which allows the storage of Dolby E audio and metadata on 24-frame systems and offers features for the coding scheme’s integration into DTV, E-cinema, telecine, and archiving applications. The DP583 frame synchronizer provides tools for the matching of externally generated signals to the broadcast, cable, and satellite facility’s internal reference.
At Digital Image, a part of the Liberty Livewire Media division housed within the former 4MC complex in Burbank, CA, Kevin Sanders has firsthand knowledge of the universal nature of Dolby E. The facility, which routinely handles both high definition and standard definition television audio, has been the ideal testbed for the coding system. Our clients are both foreign and domestic, so we have every flavor of deck that you can think of, says Sanders, Livewire Media division’s director of engineering. We do feature film archiving, mastering, up- and down-conversions for international release, DVD authoring, and restoration, and we do international distribution, foreign language, Foley, and translate it into whatever format it needs to be translated into.
Sanders reports that his staff have verified that Dolby E works with 23.98-, 24-, and 25-frame formats, 50i and 60i field rates, and every manufacturer’s video deck. Weve been doing quite a lot of confirmation of it working.
His engineers encountered a number of problematical video decks, he reports, but Dolby came up with a solution for every single time that we had a problem. The inclusion of metadata into the coded stream means that Dolby E is not only flexible, but also very robust, says Sanders. If the client has created a 5.1 mix and they want to keep it in that specific surround encoding, they can supply the encoded final product as well as the discrete mix. Just in case it ends up being duplicated a number of times and the 5.1 encoding gets degraded to the point where you cant use it any more, you’ll still have the discrete mix as well as the metadata, so it can be reproduced.
Sanders is particularly impressed with the coding scheme’s potential as an archival format, especially with its ability to store eight discrete channels. In the high definition decks, like the [Philips] D6, there are 12 channels of audio that you can put in there as six AES streams. So you can add quite a number of Dolby E encodes onto that.
Each AES pair could store eight Dolby E-encoded mono tracks, for example, or a discrete 5.1 mix plus a stereo pair, or any number of other combinations. Sanders continues, One of our clients likes to not only archive the video and the Lt/Rt and stereo mix with it, but also their entire 24-track stems. We can put Dolby E on multiple channels and end up being able to archive their stem tracks as well as the stereo mix and the 5.1.
But the true potential of Dolby E as an archival format has not yet been recognized, Sanders observes. Considering what it’s capable of, it’s not catching on as quickly as I thought it would. With the introduction of high definition and the expansion of the number of audio channels that you have available, a lot of clients are starting to look at Dolby E, because they’re now seeing that, not only can I have this, but I can have everything else as well.
Noting that he has two major clients regularly taking advantage of the abilities of Dolby E, Sanders believes the format will increase in use. Up until now, because it hasnt been widely available on all the formats, especially in high definition, it hasnt been as widely accepted in that area. But now that it has passed all its tests and is capable of being recorded in 24, 25, and 30 frame, I think we’ll start seeing a wider use of it.