While audio networking is proliferating, with a number of practical options to choose between for production, the protocol choice for sharing produced audio through the broadcast chain is much simpler. Facilities looking for an end-to-end solution for moving multichannel surround audio around in the world of television typically end their search at Dolby E. The codec offers a number of significant advantages, including the ability to carry on just two channels of multichannel bit stream, frame synchronous with video and complete with metadata, that is robust enough to survive transfers between media and transportation from production through post to broadcast.

In the opinion of Rich Macar, chief engineer, supervising sound editor, sound designer, mixer and owner of Buttons Sound, a Manhattan-based post facility specializing in audio for television, it really is a one-horse race. “Dolby has thought it through. I think that they are pretty much pioneering the most obvious choice for surround distribution. Yeah, they’re going to cash in, but they deserve to, because nobody else has thought it through. That’s my feeling; I don’t see any other way.”

Much of the power of Dolby E lies in its ability to encapsulate eight channels – which can be decoded out to many more if that includes a Dolby Pro Logic II mix – in a 2-channel AES compatible bit stream, elaborates Macar.

“That means that you have your 5.1 discrete, plus you have two channels that re usually Pro Logic II, which can play in Pro Logic and stereo as well. So it has all the formats in a stereo bit stream.”

Further, he says, “Dolby E is great because it can be put onto analog as well, so you can put it on Digibeta, and its frame-accurate, which means it can be edited and still retain the surround info. It’s a way of getting a stereo-compatible surround Pro Logic II out there. If you’re listening in Pro Logic, you’ll hear surround in an analog world.”

Being able to dub Dolby E-encoded audio onto an analog Digibeta machine, which supports just four channels of non-compressed audio, can have its advantages in the audio post world, as Macar explains. “So much today is done in HD, but producers might not have the HD master finished yet. But if they have a Digibeta version of it, I can do a surround mix. I can put Pro Logic II on tracks 1 and 2, so they have an analog surround mix for reference.”

According to Macar, he has invested in Dolby E to try and encourage his clients to begin working in surround. “When the switch [to digital television] happens in April 2009, a lot of stuff is going to be up-rezzed, because a lot of stuff hasn’t been shot in HD. But between now and then, most people are opting to shoot in HD , and anything that’s being done for the long term should be done in Dolby E. Why not? It’s not a big investment, and what we can do in surround these days is pretty amazing in the time that we can do it, compared to what it used to be.”

The versatility of a codec that can be laid back to analog or digital offers workflow advantages while also negating any need for an upgrade in video recorders or wiring infrastructure all the way through the broadcast plant, he notes. “My clients can bring their Digibeta here, and I’ll do a stereo-compatible surround mix, which can also play in Dolby Pro Logic II, on tracks 1 and 2 with the Dolby E on 3 and 4 on their Digibeta. If it goes to NBC, say, when it goes out on their standard-def feed they’ll use channels 1 and 2 and they have the surround right there for people listening in surround. Then, for their HD feed, they grab channels 3 and 4.”

That makes Dolby E a shoo-in for broadcasters, he considers. “As far as distribution, it makes perfect sense for any network or any broadcaster to use Dolby E because they don’t have to rewire anything, and all their decks have four channels. With Dolby E you’ve got 12 channels of audio, all in surround, all encoded.”

Those channels remain encoded all the way through the broadcast chain. “the beauty of it is that it keeps its integrity, through all the hubs and all the switches, until it gets to the local broadcast area. Then, they decode it to Dolby Digital and feed it out to their viewers.”

The alternative – moving discrete audio channels around – would be prohibitively expensive, as Macar observes. “I don’t see broadcasters distributing eight, 10 or 12 channels of audio up and down to satellites and all around the world. A broadcaster only needs to spend $3,000 for an encoder or decoder, so I don’t see any other way.”

For the post-production facilities upstream of the broadcaster, it may not even be necessary to invest in Dolby E, thanks to its flexibility. Macar explains, “You can dub it right through the analog converters or even D-to-D, just take a Digibeta and dub the audio right to a [digital] D5. If my client is going to color-correct, they can give me a Digibeta and I’ll do a surround mix and lay it back onto Digibeta. Meanwhile, they do their color correction and put it on a D5. They can then dub directly from the Digibeta to the D5, and they have the Dolby E and surround sound and they don’t even need to own any decoders or encoders.”

There’s no real downside, Macar believes, although there is one potential “gotcha.” As with any piece of digital audio equipment there is a latency issue, and the encode-decode cycle introduces delay. “There is a one-frame and two-frame offset that people are dealing with,” he reports. “It was recommended to me that before I lay back to Digibeta that I move my Pro Tools project two frames earlier so it will get one frame back when I’m playing back, and when it goes to air it will pull that audio up.”

As the industry transitions to an all-digital paradigm in television, digital latency in the audio chain is just one example of the learning curve facing everyone involved, believes Macar. “There’s a lot of stuff that’s one and two frames off on television right now. It’s that minutiae that’s going to be the focus a few years from now.”