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Author
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Topic: Dolby's new sound system
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Bobby Henderson
"Ask me about Trajan."
Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001
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posted 04-26-2012 11:10 AM
quote: Mike Blakesley
And, Bobby H -- a $25,000 upgrade to a sound system probably won't cause an additional upcharge.
With all the extra amplifiers required, addition of new speakers, rewiring & re-aiming existing speakers (and the purchase of the Dolby Atmos processor) I really have to wonder.
The upgrade is not going to be cheap. And it will take considerably more work to set up properly and maintain properly. Speaker drivers eventually fail and have to be replaced. Amps can fail too. You guys have heard me frequently complain about regular 5.1 digital sound systems not being well maintained. Dolby Atmos will require a theater operator to be a lot more on the ball with the sound system. There will be a lot more parts that can fail.
quote: Carsten Kurz
Atmos doesn't use parallel tracks but audio objects.
Every audio "object" is still going to consume its own share of hard disc space (16 or 24 bits times the 48kHz or 96kHz sample rate) for its duration on the time line.
Sound designers will organize these audio objects onto their own layers and even layer groups in DAW (digital audio workstation) software like ProTools, Logic Studio, Audition, Sound Forge, etc.
In any modern mix for movies or TV dozens of individual sound elements can all playing simultaneously along the time line. That many audio elements playing at the same time can create a much larger bit per second bandwidth playback demand than you'll get from a standard 5.1/7.1 linear PCM track. The I/O bandwidth can reach the point of requiring RAID for real time playback. The completed DAW work files for a 1 hour TV show or 2 hour movie can easily weigh hundreds of gigabytes.
quote: Carsten Kurz
What's so complicated to understand that the actual audio mix is not done on the studios mixing stage, but in the auditorium sound processor?
Actually the sound design still has to be done in the studio, mixing stage, etc. The Atmos concept just seems like it is trying to take the finished DAW sound design files and play them in the movie theater without down-mixing them to 5.1/7.1 audio stems.
That approach may be practical as long as there is enough hard disc space to hold the audio content and the system can handle peak bandwidth demands.
I have a feeling at least some down-mixing has to occur and then Atmos audio effects will be piggy-backed on top of it. For instance, the music score may still be down-mixed to a 5.1/7.1 stem rather than featuring discrete audio elements for each musical instrument.
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Manny Knowles
"What are these things and WHY are they BLUE???"
Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002
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posted 04-26-2012 03:45 PM
quote: Mike Blakesley
And, Bobby H -- a $25,000 upgrade to a sound system probably won't cause an additional upcharge.
<<---- falls off chair laughing.
...but seriously...
It seems that up-charging is the new "in thing." Theatres love it, and audiences tolerate it. So I totally expect to see theatres up-charging for Atmos. At the very least, I expect them to try.
BTW, the stronger rationale would be based upon the perceived added value, not the installation cost.
Now...
...would theatres get away with double up-charges for a 3-D movie presented with Atmos sound???
Another thought -- One would hope that Atmos-equipped theatres will specify how many (loudspeaker) channels are available.
"Atmos Mono" and "Atmos 5.1" could theoretically exist, right? quote: Bobby Henderson
The main thing I'm wondering is whether a Dolby Atmos track can be included in the same DCP hard disc with the JPEG2000 image stream and 5.1/7.1 LPCM tracks for the vast majority of other d-cinema theaters. Or will the Atmos track be a separately shipped or Internet-streamed item? Is the Atmos track going to be played straight from a Dolby Digital Cinema server alongside the video or will it be something that needs to be loaded separately into the Atmos processor?
Granted, I didn't read the whole thing cover-to-cover, but I think there's a hint of how this will play out in one of those PDF's.
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Carsten Kurz
Film God
Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009
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posted 04-26-2012 04:02 PM
Bobby - do the math yourself. Worst Case 128 channels is 16times as much as a conventional 7.1 track file. But whereas a 7.1 trackfile will always have all 8 tracks occupied throughout the feature, an Atmos dataset will hardly ever have all 128 channels occupied throughout the full feature. Even if: It will result into an absolut maximum of about 130GBytes for a 2hr feature. A typical DCP has between 120-200Gbytes. Could contain multiple features. Now how cares wether the DCP harddisc needs to be a 500GB instead of a 320GB disc? The cinema doesn't care.
Most basic information regarding the content distribution and handling is covered in the PDFs.
According to Dolby, the Atmos mix is streamed from an Atmos enabled DCI server to the Atmos cinema processor over Ethernet. Wether that is actually streaming or a file based access with caching methods or not - who cares, Dolby would have done a bad job if they couldn't sustain the necessary datarates. The easiest method would be simply downloading the Atmos file to an internal SSD in the Atmos processor which has all the thoughput needed for this kind of performance.
And so far, only Dolby servers can deal with the Atmos mix. We will see wether other servers will be enabled at some time. Some thing happened with Dolby 3D.
I really don't see why anything that Dolby promises couldn't be met by todays hard- and software. Nobody will ever use simultaneous playout of 128 objects anyway. At least that is certainly not the hard performance limit of this system, there are probably others. And if it failed, it would be noticed already on the mixing stage and they would find solutions like partial downmixes.
The wiring effort could be reduced a lot by supplying dedicated 'Smart Speakers' with built in DAC and PowerAmp and special cabling for supply and digital daisychained audio, as available with some ProAudio-over-Ethernet standards. Wouldn't be cheap, but in high volumes as needed for Atmos installations...
- Carsten
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Manny Knowles
"What are these things and WHY are they BLUE???"
Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002
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posted 04-26-2012 06:38 PM
I'm not worried about file size -- who cares how big the file is?
Nor am I concerned about processing. Pro Tools hardware (formerly Digidesign, now Avid) has been playing and processing hundreds of tracks simultaneously for years now. And, I should hasten to point out that -- in a mix situation -- a Pro Tools system is doing more than just multichannel panning. This kind of playback system won't be called upon to apply filters, EQ, compression, reverberation, fader moves and so on. Just panning. Shouldn't be a problem.
Y'know...In hindsight, I'm shocked we didn't see this sooner. It's a very elegant concept.
BTW, any Sound Effects Editor who re-used the same 10 punches over and over (in one film) wouldn't stay working for very long. At USC, we couldn't even get away with that on our STUDENT films. Traditionally, a body hit (like a punch) is a combination of various elements. An actual punch doesn't sound anything like what you hear in a movie. It's highly constructed and a lot of thought goes into EACH hit. There's a reason those people make the money that they make.
And, yeah -- BAN the "Wilhelm yell." Please! ![[puke]](graemlins/puke.gif)
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