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Workflow issues are significantly impacted by the new multichannel environment. How they are dealt with varies — a storage area network (SAN) is an almost knee-jerk reaction in the video domain, where huge files are standard, but multichannel audio files can still be handled by localized data solutions. Ascent Media Creative Service’s six Los Angeles-area audio facilities, including Todd-A/O, 4MC and Soundelux, are linked via a 1000 BaseT fiber-based ethernet supplied by Pac Bell utilizing standard Mac OS X servers that provide about 36 TB of storage, plus another 70 TB of removable storage. The sheer size of the system was dictated in part by increased demands, because so much of its audio work now includes multichannel elements, says Bill Johnston, Ascent Media’s senior vice president of engineering, who supervised the system’s installation. However, Johnston emphasizes, it’s data management, rather than just storage, that was paramount. For that, the SANs available today were too costly and complicated for audio applications, even complex feature film post.
"SANs are hot topics right now, but it’s not the most efficient approach," Johnston explains. He cites the volume-based architecture of SANs, which is at odds with the file-based architecture that he says will become available at a lower cost in software and human resource management.
Imagine an entire year’s worth of this magazine bound into a volume. Accessing a single issue requires requesting the entire volume from a server in order to write changes across all the files in the volume. Johnston argues that selecting individual files from a central server — what’s known as a "push-pull" approach to data retrieval — is more efficient for audio post, given the size of its files. "In researching and testing various systems, we found that switching to the Mac OS X platform and away from Windows gave us the fastest multi-user large-file transfer rates," he says. Johnston says the strategy also involved basing the system around off-the-shelf technology, minimizing the need for customization and for a dedicated staff to manage a SAN. "The system is built around the speed of downloads from the servers. That’s how we address the workflow issue." He says he’s seen SANs implemented at other large post facilities. "The problem is that many people can read the files, but only one person or station at a time can write to the volume. And you can’t have two different Pro Tools systems working off the same volume because Pro Tools requires that you write directly to the drive. That’s a huge limitation to workflow economics."
Sony Music Studios in Manhattan, which shoots and posts projects such as music videos and the VH1 show Storytellers, currently utilizes similar drive-based server systems but plans to implement a SAN based on Apple or Hitachi components. "The throughput argues for it," explains Davis Smith, vice president of engineering. "It’s grab-and-go versus save-and-capture. It’s simply quicker." Smith says that 5.1 audio is pressuring facilities to expand data storage and management, as is the increasing sheer number of audio elements in television projects. He also likes the SAN’s inherent back-up regimen of automatically replicating itself with every update. "This is all about economics," he says. "But you have to understand, it’s not related to the size of the files — it’s all about the speed of action. You push a button and go. The more work we can push through the facility — the faster we can push it, the more we can bill. The SAN makes more sense because it’s always there. It’s always on, unlike a server-based system that you have to retrieve from." Still, Smith acknowledges that upfront costs will be higher and that he will have to dedicate a staffer to act as system supervisor. "On the other hand, we have 25 Pro Tools systems here and two guys who do nothing but maintain them. It’s simply what’s necessary in terms of allocating human resources as technologies change."
At Crawford Communications in Atlanta, Steve Davis, director of audio, also has a 1 GB ethernet server system, but he plans to keep it in place. "What we’ve found is that in spot work, projects tend to start and finish in the same room," he says. "The SAN has its greatest value when projects are shared or moved around from room to room." Even the longform work done at the facility — which has an Avid Unity SAN for video post-production – will have 5.1 audio elements imported via OMF from the video editing side. The facility’s large, centralized sound-effects database uses Soundminer to perform Boolean searches and then downloads the results to the appropriate audio edit suite. In fact, says Davis, a server-based approach with its file-friendly methodology seems to work better for multichannel sound effects. "We’re moving in the direction of prerecorded 5.1 effects," he says, "but for the time being, they tend to be custom-assembled per project and they need to stay that way even after the project is tentatively done. Let’s say you’ve assembled a dog and cat together as a 5.1 effect. The producer comes in on the tenth edit and decides the cat doesn’t work, or it’s in the wrong spatial relationship to the dog and the rest of the cut. You have to keep all of the elements separated as well as together because a 5.1 effect has a spatial component that a simpler stereo effect doesn’t. The spatial aspect of the effect becomes part of its sound."
Ascent Media’s Johnston says he would consider a SAN approach, but wants to see one in which access and write permissions are based on a file-by-file basis. There are systems out there that can do that, such as Apple’s X-SAN and Rorke Data’s ImageSAN. Bob Herzan, vice president of worldwide sales for Rorke Data, doesn’t argue the point. "A SAN at the file level is more complicated to manage," he agrees. "And while audio files are getting larger as a result of more 5.1 elements, they’re still not nearly as huge as video files. So it makes sense that video post is going to get more initial benefit out of a SAN. However," he adds, "convergence is also an issue. At some point, having all of the elements — video and multichannel audio — in the same repository will have a lot of advantages for workflow."
Another difference between the SAN and the central server approach is the implementation of the systems. Johnston made a point of searching out a solution that could be designed and assembled in-house, but SANs are more complex. Dave Van Hoy, president of Bay Area system integrator Advanced System Group, says the decision should be based more on the level of management sophistication required than the amount of storage needed. "Storage is cheap today, now that there’s no real return on investment in buying a SAN on the basis of reducing storage costs," he states. Two years ago, a terabyte of storage cost about $25,000. Today, 4 TB costs about $13,000. But other system components costs add up. A typical eight-port switch addressing up to three DAWs costs about $4000, and Van Hoy estimates you’ll spend about $1000 per seat for management software. Compare that with an estimated $7000 for 2 TB of space on a RAID-5 system.
Advanced Systems Group has installed about $500,000 worth of SAN systems in the last half of 2004, and only about 10 percent of those went into audio-only post facilities. "The average Pro Tools system can run off a $250 FireWire drive, and you don’t need me to hook it up," Van Hoy says. "But as 5.1 increases the amount of data that audio takes up, and more projects require 5.1, we may be getting together at some point in the future."
Intercompatibility
The SAN sector until recently has been a proprietary domain with little interoperability between components from different manufacturers and virtually none between software management systems — which almost never support more widely used desktop management systems and other business management and database software, such as Excel. In fact, say some observers, it’s the software side of the business that’s most resistant to change and compatibility, because as the cost of storage itself continues to drop so precipitously, the software is where the profit margin in the business is.
SANs are still very much computer creatures, and that sector’s trade press has covered the issue extensively. A recent report in Computerworld magazine quotes Ray Dunn, chairman of the storage management forum, as stating, "The overhead and complexity of storage has created agent proliferation and islands of data, just what a SAN is supposed to fix."
That’s beginning to change, thanks to several initiatives, most notably one from the Storage Network Industry Association (www.snia.org), which has been arguing for wider compatibility among SAN equipment manufacturers. The group has launched an initiative to promote cooperation among equipment and software makers. The group’s Australia and New Zealand chapter is supporting a new specification known as the Storage Management Initiative Specification (SMI-S), a uniform standard interface for managing storage devices. It is expected to become widely used in 2005.
Workflow With and Without a SAN
Comparing the workflow models of SAN- and server-based facilities is illuminating. At Doppler Studios in Atlanta, engineer Fay Salvaras works regularly on projects for Cartoon Network, and the number of multichannel projects is increasing. Doppler’s system is a 1.5 TB RAID-5 array. Salvaras logs in at the start of a session and downloads broadcast.wav files from the server for the facility’s Mac-based Pro Tools systems and its Windows-based Waveframe DAWs. It takes about five minutes to identify, select and load the data. If a conversion is needed between audio platforms, Salvaras makes an OMF file and transfers it between platforms via the server. Each day’s work is backed up to either a CD or DVD, depending upon file size. (Most projects average around 300 MB, she says; the largest has been 10 GB.) After hours, staffers will back up all the day’s work to AIT tapes and make a redundant CD or DVD.
"A SAN has the ability to make simultaneous backups, which is nice," she concedes. "But this workflow approach is fine for most of the projects we do. If it gets to the point where it takes an hour to load audio files at the start of a session and causes a workflow bottleneck, then it’ll be time to reconsider."
At Skywalker Sound, a fiber-channel SAN streamlines workflow, in addition to providing security and redundancy, says Tim McGovern, director of engineering. At the beginning of a project all relevant material (video, audio, EDL) is ingested into the SAN and placed in pre-allocated volumes. As the show develops, movement of audio from one room to another is achieved by controlling access to the data files. Management of the SAN arbitrates read/write access. Multiple users may be allowed to play back material but only one can update it. It is this multiple read feature that has had the most dramatic effect on the process, says McGovern. In addition to the regular disaster-recovery backups that take place at regular intervals (to geographically separate storage), client backups on a choice of media are available as part of the project’s deliverables.
"From a workflow perspective, simultaneous read access lets the stage that is premixing dialog play FX premixes as soon as they are created, while the FX mixer continues to build up further layers for the same reel," he says. "It also allows editors to conform a reel while the stage is still working on the previous version. Not only has the SAN reduced the storage requirements since only one set of audio files exist but it’s also made the tracking of material almost automatic. Inherent in the network management is the ability to know who has access to what and from where."
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