16 The broadcast object (continued)
“On the immersive side, the recently announced Atmos for Home Theatres has reference setups that include both 5.1.2 (5.1 system plus 2 ceiling speakers) and 7.1.4 configurations (7.1 system plus four ceiling speakers).”
Interestingly, the idea of height doesn't necessarily have to come with physical speakers. Prin notes that Atmos-enabled speakers have been developed to create overhead sound, from a few feet off the floor, by firing sound upward that reflects off the ceiling.
A core message here is flexibility. A broadcaster could send a 5.1 mix, separate mono dialogues, 4.0 crowd options - with the experience determined by the user and the rendering guided by metadata in the AC-4 stream. Further, the metadata carries spatial information, so the experience is tailored to the system it is being played on.
"You can imagine that if you want to transmit all these multiple dialogues then good clean speech performances and low bit rates for all of those feeds becomes quite useful."
AC-4 (
etsi.org) is coming out in two main parts. Part 1 is already published, with Part 2 bringing further enhancements -
Dolby Atmos update
Atmos has exceeded Dolby's expectations by quite some margin, but cinema refurbishments take time, and committing to doing an Atmos mix first then rendering to 7.1 is a big step for many - even though it's a potential time and money saver.
The great thing about the world of Atmos, even at this relatively early stage, is that in production the discussion has become creative. Some spectacular examples of Atmos soundtracks have been well documented, not least the Oscar winning Gravity, which saw Glenn Freemantle of Sound 24 add a few expletives to the established language of film sound, and the sublime Life Of Pi, which even though it was an early Atmos trial, found a new freedom for its music through Atmos.
This has been, according to Dolby's Nick Watson (Technical Marketing Manager), one of Atmos' creative headlines: "I was certainly surprised that the music community has embraced objects in quite the way they have. I thought music would be the last thing to become 'objectified'.
"A lot of mixers have started putting music in the front side surrounds - what are being dubbed the 'widest speakers' - the left-wide and right-wide... It frees up the screen channels for dialogue and effects and gives a wider stereo image as well.
"There is also a lot of benefit to be gained from putting some aspects of the music into the overhead beds, though actually what seems to be a little more effective is if you take out some of the music elements and place them as music objects in the overhead array. It gives more separation... You don't necessarily know that you're hearing it from above you or
hhb.co.uk
from a discrete point in the side array, but it just gives the music a definite sense of space. That's what a lot of music mixers, editors, and composers have really enjoyed.
The idea of treating reverbs as objects was another relatively early adventure and has worked well for many mixers. "It was something we didn't initially see happening," says Watson, "Because in the first year we didn't have object 'size' control in the plug-in. We introduced that last year and it means that any reverb can be returned as an object with size, either replicating channel-based reverb or making it slightly more controlled and being able to put different reverbs in different parts of the room."
One thing that Gravity got straight (amongst others) was the contentious issue of dialogue panning. Before the luxury of full range surrounds and the panning resolution that Atmos brings, many branded it an unforgivable sin. In Gravity, however, Freemantle took advantage of the technology, and the environment, to keep the audience spinning along with the astronauts - a surprisingly natural experience thanks to the skill and care with which it was mixed.
With eyes on the horizon, in a utopia where bandwidth is ample and budgets are able, there is no doubt that the prize AC-4 seeks is delivery of more Atmos-like object audio into the home, into the mobile device, and into the car. The more imminent challenges for production are simply providing and producing additional presentation material, and being able to monitor those feeds during broadcast.
For now, Dolby is working to have Part 1 entered into the DVB Broadcast standards to provide a start-of-the art solution for today’s needs that will scale to support these new experiences
"The syntax for choosing streams is supported in Part 1. There are things called 'presentations' in there which allow you to do that. But it's not a full-blown object system yet."
Part 2 will bring in the object metadata, additional channels (Part 1 is up to 7.1), and more. However, one big feature - dialogue enhancement technology, is already in Part 1. "The encoder can try to analyse the dialogue source in 'blind mode' (single ended)," explains Prin, "And send information to the receiver so you get some degree of control. Providing separate dialogue is ideal because, obviously, it gets the clean feed..."
In broadcast the object, or the element, is a new toy for the customer, provided at the discretion of the content creator. The final question might be how much control should the viewer or listener have? Is a broadcast best left as a presentation or is it really time to empower the consumer? In time this might turn out to be the big creative decision...
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40