Surround Processing Moves From Standalone to Integrated Technology

Surround processing — the automated upmixing and downmixing between mono, stereo, and 5.1 sound elements — at the high end of the scale isn’t quite at the commodity stage yet. But it is following a predictable path that sees its algorithms migrating from standalone branded systems to chipsets integrated into other products.

For instance, DTS’s Neural Surround upmix (along with its MultiMerge and loudness-management software) can now be found as an card-frame option in Harris’s X85 multi-app AV platform and as a plug-in for Avid’s ubiquitous Pro Tools system. Linear Acoustics’ upMAX surround upmixing technology has been integrated into Cobalt Digital’s 9305 embedded audio-delay processor.

The licensing trend has been in place for a couple of years, getting the technology into new places via card frames and into non–real-time applications for file-based processing, says Linear Acoustics President Tim Carroll. “It’s a way to get the technology where it’s needed when customers request a form factor that we don’t have.”

Although this kind of integration is expected as part of normal technology market evolution, Carroll believes that standalone products remain viable. “I didn’t think we’d ever have another standalone upmixing product, but the upMAX II was released that way,” he says, attributing the demand in part to the growing number of owner-operated stations that want more-consistent 5.1 surround audio in their broadcasts. “There are thousands of channels of upmixing out there; we can’t make them fast enough,” he says, noting that the situation has helped keep pricing fairly steady.

Takin’ It to the Streets
This integration of functionality is in reaction to several forces, including purchasing departments’ looking for more multifunction bang for broadcasters’ bucks. But it bodes well for extending upmix-processing potential beyond the major networks that pioneered its use. “Everyone is looking for a seamless surround experience,” says Dave Casey, product manager at DTS. “It would not surprise me to see [upmixing] trickle down to regional sports broadcasting in the future.”

That’s a cornerstone of the strategy of the most recent entry into the upmix domain. Penteo’s Post Pro has gained some traction with multichannel music recordings and in Hollywood (it was used to create the 5.1 surround sound for 2009’s Inglourious Basterds), which suggests applications in sports-broadcast pre- and post-production. Penteo Founder/CEO John Wheeler, who mixed baseball and wrestling two decades ago at TBS, says the ability to forensically analyze a stereo track allows the technology to accurately extract and position audio elements into five discrete “slices.” Being able to do that for $5,000-$9,000 per unit — less than half the cost of more currently entrenched upmix products — could offer regional sports broadcasters the ability to generate 5.1 surround broadcasts from within a stereo infrastructure.

The Penteo Post Pro has a 0.3-second latency as a function of its processing. Wheeler says it is being introduced to the sports-broadcast universe through inclusion in Orban’s 8685 processor, where it detects stereo program material, automatically upmixes it, and builds in a video delay to match the Penteo latency.

He emphasizes that, in addition to being a value proposition, the technology offers all broadcasters the ability to create consistent 5.1 surround upmixes using existing two-channel infrastructure. “There’s not one Comcast truck that could not benefit from Penteo right now,” he says.

Getting Creative
In some cases, upmix/downmix propositions are offering users more creative flexibility beyond the basic parameters programmed into their algorithms.

DTS’s Casey notes that users of Neural Surround upmix can fine-tune sound-field width and depth, channel layout, output levels, LFE filtering, and final limiter.  “There’s more upmixing and downmixing going on at the mix stage, especially when the engineer, in an effort to preserve the surround effect, brings audio back from EVS systems for replays that use legacy stereo audio.”

He also points out that upmixing offers the user flexibility, providing the ability to affect depth and width parameters, channel levels, and other independent adjustments even if the pre-produced music, effects, and announcers were not produced perfectly the first time.

However, he adds, the extent to which users can affect depth and width parameters has to be limited to some extent, to avoid distorting the relationships of the axes. “They need to stay in proportion to each other so that the surround effect remains in place,” he says. “You can influence the but not radically change their relationships.”

Another variation on the upmix theme is what Casey calls 4.0 mode: creating a four-channel surround effects mix (less the center channel) from a stereo source or a “nat sound” mix that can be used essentially as a stem in postproduction, with dialog added in the center channel later.

In the imminent age of 3D, 5.1 and, to some extent, 7.1 surround audio will take on even more importance for sports broadcast. That will also assure the industry a robust set of technology choices.

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