First Look: Thunderbolt Capture Devices
Over the years media pros have seen data protocols come and go. Some, like Fibre Channel, are still current fixtures, while others, such as SCSI, have bitten the dust. The most exciting new technology is Thunderbolt, which is a merger of PCI Express and DisplayPort technologies co-developed by Intel and Apple. Started under the code name of Light Peak, the current implementation of Thunderbolt is a bi-directional protocol that passes power, video display signals and data transfer at up to 10Gbps of throughput in both directions. According to Apple, that's up to twelve times faster than FireWire 800. It's also faster than Fibre Channel, which tends to be the protocol of choice in larger facilities. Peripherals can access ten watts of power through Thunderbolt, too. Like SCSI and FireWire, Thunderbolt devices can be daisy-chained with special cables. Up to six devices can be connected in series, but certain devices have to be at the end of the chain. This is typically true when a PCIe-to-Thunderbolt adapter is used.
A single signal path can connect the computer to external storage, displays and capture devices, which provides editors with a powerful data protocol in a very small footprint. Thunderbolt technology is currently available in Apple iMac, MacBook Air, MacBook Pro and Mini computers and is starting to become available on some Windows systems. It is not currently available as a built-in technology on Mac Pros, but you can bet that if there’s a replacement tower, Thunderbolt will be a key part of the engineering design.
By its nature, Thunderbolt dictates that peripheral devices are external units. All of the processing horsepower of a PCIe card, such as a KONA or Decklink, is built into the circuitry of an external device, which is connected via the Thunderbolt cable to the host computer. I took a look at three Thunderbolt capture/output devices for this article: AJA Io XT, Blackmagic Design UltraStudio 3D and Matrox MXO2 LE MAX. The Io XT is AJA's only Thunderbolt product (prior to NAB), whereas Blackmagic Design has developed three Thunderbolt units at difference price tiers. For smaller installations, the Intensity Shuttle Thunderbolt or Intensity Extreme are viable solutions.
Matrox has taken a different approach by using an adapter. Any of its four MXO2 products -- the standard MXO2, Mini, LE or Rack -- can be used with either Thunderbolt or non-Thunderbolt workstations. Simply purchase the unit with a Thunderbolt adapter, PCIe card and/or Express 34 slot laptop card. The MXO2 product is the same and only the connection method differs for maximum flexibility. The fourth company making Thunderbolt capture devices is MOTU, but their HDX-SDI was not available in time for this review.
All three of these units include up/down/cross-conversion between SD and HD formats and perform in the same fashion as their non-Thunderbolt siblings. Each has pros and cons that will appeal to various users with differing needs. For instance, the AJA Io XT is the only device with a Thunderbolt pass-through connector. The other units have to be placed at the end of a Thunderbolt path. They all support SDI and HDMI capture and output, as well as RS-422 VTR control. Both the AJA and Blackmagic units support Dual-Link SDI for RGB 4:4:4 image capture and output. The Matrox and AJA units use a power supply connected via a four-pin XLR, which makes it possible to operate them in the field on battery power.
The need to work with legacy analog formats or monitoring could determine your choice. This capability represents the biggest practical difference among the three. Both the MXO2 LE and UltraStudio 3D support analog capture and output, while there's only analog output from the Io XT. The MXO2 LE uses standard BNC and XLR analog connectors (two audio channels on the LE, but more with the MXO2 or Rack), but the other two require a cable harness with a myriad of small connectors. That harness is included with the Blackmagic unit, but with AJA, you need to purchase an optional DB-25 Tascam-style cable snake for up to eight channels of balanced analog audio.
One unique benefit of the Matrox products is the optional MAX chip for accelerated H.264 processing. In my case, I tested the MXO2 LE MAX, which includes the embedded chip. When this unit is connected to a Mac, Apple Compressor, Adobe Media Encoder, Avid Media Composer, Telestream Episode and QuickTime perform hardware-accelerated encodes of H.264 files using the Matrox presets.
Fitting Into Your Layout
I ran the Io XT, UltraStudio 3D and MXO2 LE through their paces connected to a friend's new, top-of-the-line Apple iMac. All three deliver uncompressed SD or HD video over the Thunderbolt cable to the workstation. Processing to convert this signal to an encoded ProRes or DNxHD format will depend on the CPU. In short, recording a codec like ProRes4444 will require a fast machine and drives. I haven't specifically tested it, but I presume this task would definitely challenge a Mac Mini using only internal drives!
The test-bed iMac workstation was configured with a Promise Pegasus 6-drive RAID array. The iMac includes two Thunderbolt ports and the Pegasus array offers a pass-through, so I was able to test these units both directly connected to the iMac, as well as daisy-chained onto the Promise array. This system would still allow the connection of more Thunderbolt storage and/or a secondary computer monitor, such as Apple's 27" Thunderbolt Display. Most peripheral manufacturers do not automatically supply cables, so plan on purchasing extra Thunderbolt cables ($49 for a six-foot cable from Apple).
These units work with most of the current crop of Mac OS X-based NLEs; however, you may need to choose a specific driver or software set to match the NLE you plan to operate. For instance, AJA requires a separate additional driver to be installed for Premiere Pro or Media Composer, which is provided for maximum functionality with those applications. The same is true for Matrox and Media Composer. I ran tests with Final Cut Pro 7, X and Premiere Pro CS 5.5, but not Media Composer 6, although they do work fine with that application. Only the UltraStudio 3D will work with DaVinci Resolve. In addition to drivers, the software installation includes application presets and utility applications. Each build includes a capture/output application, which lets you ingest and lay off files through the device, independent of any editing application.
Broadcast Monitoring and FCP X
The biggest wild card right now is performance with Final Cut Pro X. Broadcast monitoring is a beta feature added in the 10.0.3 update and the third-party drivers are still in the development stage. Separate FCP X-specific drivers may need to be installed. If you intend to work mainly with Final Cut Pro "legacy" or Premiere Pro, then all of these units work well. On the other hand, if you've taken the plunge for FCP X, I would recommend the Io XT. I never got the MXO2 LE MAX to work with FCP X and initially the UltraStudio 3D wouldn’t work either, until the latest version 9.2 drivers that Blackmagic posted mid-March.
The Io XT was very fluid and tracked FCP X quite well as I skimmed through footage. FCP X does not permit control over playback settings, so you have to set that in the control panel application (AJA) or system preference pane (Blackmagic Design and Matrox) and relaunch FCP X after any change. The UltraStudio unit also tracked FCP X reasonably well, though started to cause image freezing when fast-forwarding the timeline at 2X or faster. This situation is still in flux and will likely improve in the coming months, but for now, FCP X broadcast monitoring is clunky at best.
The broadcast monitoring feature in FCP X does not add any new VTR control or ingest capability and it's unlikely that it ever will. To ingest videotape footage for FCP X using Io XT or UltraStudio, you will have to use the separate installed capture utility (VTR Xchange or Media Express, respectively) and then import those files from the hard drive into FCP X. Going the other direction requires that you export a self-contained movie file and use the same utility to record that file onto tape. The Matrox FCP X drivers and software currently do not include this feature.
Finally, the image to the Panasonic professional monitor I was using in this bay matched the FCP X viewer image on the iMac screen using either the Io XT or UltraStudio 3D. That attests to Apple's accuracy claims for its ColorSync technology.
Performance with the Mainstream NLEs
Ironically the best overall performance was using the end-of-life Final Cut Pro 7. In fact, all three units were incredibly responsive on this iMac/Promise combo. For example, when you use a Mac Pro with any FireWire or PCIe-connected card or device, energetic scrubbing or playing files at fast-forward speeds will result in the screen display and the external output going quickly out of sync with each other. When I performed the same functions on the iMac, the on-screen and external output stayed in sync with each of these three units. No amount of violent scrubbing caused it to lose sync. The faster data throughput and Thunderbolt technology had enabled a more pleasant editing experience.
I ran these tests using both a direct run from the iMac's second Thunderbolt port, as well as looped from the back of the Promise array. Neither connection seemed to make much difference in performance with ProRes and AVCHD footage. I believe that you get the most data throughput when you are not daisy-chaining devices, however, I doubt you'll see much difference under standard editing operation.
The best experience with Premiere Pro was using the Matrox MXO2 LE MAX, although the experience with the AJA and Blackmagic Design devices was fine, too. This stands to reason, as Matrox has historically had a strong track record developing for Adobe systems with custom cards, such as the Axio board set. Matrox also installs a high-quality MPEG-2 I-frame codec for use as an intermediate preview codec. This is an alternative to the QuickTime codecs installed on the system.
Since I’ve tested these products prior to NAB, expect some new announcements from these manufacturers and NLE software developers. I suspect you’ll hear about driver updates, new features and additional supported applications to come from the show.