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FreshDV AJA IoHD Case Study

Putting ProRes Capture to the Test with Today's HD Cameras

By Matthew Jeppsen

Several months ago FreshDV conducted a series of High Definition camera tests in Chicago, IL. Thanks to the kind support of several local Chicago rental houses and partners we were able to secure the Panasonic Varicam, Panasonic HPX-3000, Panasonic HVX-200, Sony F900, Sony XDCAM PDW-350, and Sony XDCAM PMW-EX1 for our tests. We also had a fully-equipped RED Digital Cinema package on-set, and a 35mm Arri camera for baseline film comparison.

In addition to shooting test charts and gathering data on each camera, one of the major goals of the test was to create a comparative, controlled real-world studio shooting situation that would stress each camcorder and show the unique strengths and weaknesses of each system's codec, lens, and imager. To that end, we decided that each camcorder's test would be shot in its native recording format and codec, as well as an additional uncompressed reference capture for comparison. Shooting in this manner would enable us later to overlay native compression vs. uncompressed on a NLE timeline, and use a difference matte to show how compression was affecting the image. The challenge was that each HD camcorder offered differing formats, resolutions, framerates, and output features. So we knew that capture and image monitoring was going to be an issue to be addressed well in advance.

After speaking with HD consultant Mike Curtis, we opted to use Apple's new 10-bit ProRes 422 HQ codec as our "uncompressed" baseline master. While ProRes is technically a lossy codec, it is widely noted by Curtis and others that the quality loss is trivial and virtually imperceptible from uncompressed captures. And the disk speed requirements for ProRes are far less stringent than for uncompressed. This solved a lot of problems on the capture side of this test. The one remaining wild card, connectivity, was solved when we contacted AJA and they provided us with an IoHD "do everything" box. The IoHD is a sleek 7 lb aluminum box that offers a host of input and output options, can transcode virtually anything to ProRes 422 in realtime, and does it all via a single Firewire 800 cable. The IoHD was announced at last year's NAB Show, and has been shipping since the fall of 2007.

IoHD IoHD

The back of the IoHD offers practically limitless connectivity options; HDMI, Component, S-Video, SDI, XLR audio, AES audio, external sync, linear time, and RS-422 deck control. With the exception of a power switch, there are no physical controls on the box itself...everything is routed and controlled via the IoHD software control panel running on the computer. This control panel is surprisingly intuitive, and allows full control over routing of where a signal comes and goes within the box. We could take a component input from the Panasonic HVX-200, for example, and reroute that back out to the Panasonic BT-LH1700W broadcast monitor for calibration, focus and monitoring…all while simultaneously capturing our Uncompressed master reference in ProRes HQ.

Setup of the IoHD is relatively trivial. It requires installing the IoHD control panel software and then connecting the IoHD to the computer (a 17" MacBook Pro 2.6 GHz in our case) via Firewire 800. As the MacBook Pro only offers a single Firewire 800 connection, and the IoHD requires the entire bus (no, you cannot get around this limitation, we tried), we opted to use an external eSATA hard drive for ProRes captures, which was connected via an eSATA ExpressCard adapter. The only issue we ran into on setup was the fact that the IoHD must be connected to the computer and powered on before booting the computer. This means that if you disconnect the IoHD box for any reason, you must reboot the computer before it will see the IoHD again. This was an occasional irritation, but not a deal breaker in our situation. We also had some problems with our eSATA drive (Western Digital My Book Home Edition-750GB) going into a sleep mode and not waking up properly. Whenever the drive did this, it necessitated a computer reboot before FCP would see it again. This may have been due in part to our particular eSATA adapter card. It didn't pose too much of a problem once we realized what was happening…we quickly figured out that manually accessing the drive every 10 minutes or so would keep it from sleeping. In retrospect, it would have been nice to have a utility like Disksomnia to avoid this issue. I should stress that this issue appeared to be drive and/or eSATA adapter related and did not appear to be the fault of the IoHD unit.

Our on-set workflow was essentially this; connect the HD-SDI or component video input to the back of the IoHD, and then route the signal back out to the production monitor (physically with cables and also by toggling on those settings in the software). At the same time, the IoHD was converting the incoming signal to ProRes 422 HQ in realtime, which we captured over the Firewire 800 bus via Final Cut Pro to a commodity eSATA hard drive connected to a MacBook Pro laptop. Think about that for a second...any input could be rerouted out for monitoring, while at the same time capturing a virtually lossless HD video stream to a sub-$200 hard drive attached to a typical laptop computer. No fancy high-speed RAID, no crazy hoops to jump through. That is powerful. When the IoHD software is installed, it creates a number of custom capture presets in FCP, so setting up each capture is trivial. When you can simply pick a preset out of the list labeled "Varicam," it takes a lot of the thinking and guesswork out of the equation.

In conclusion, the system worked beautifully, and enabled us to move very quickly with our tests. The unit ran quiet and cool, and we completed our two days of testing on time. Having a ProRes 422 master really allowed us to dig into where each camera and system fell apart...determining if the breaking point came from the codec or the camera system itself. It also solved our monitoring and connectivity issues with ease. To that end, the IoHD was an invaluable tool on set that made its $3500 price tag seems trivial. While it is a system with a specific strength and focus, it delivers in that area with near perfection.

You can view a short video from FreshDV's test set that shows our IoHD workflow, at http://freshdv.com/go/iohd/

Look for the results from FreshDV's HD Camera Shootout in the coming weeks at http://www.freshdv.com


Matthew Jeppsen is a freelance HD shooter and editor. His reel is at ClearCreekProductions.com. Matt writes about today's film/video tools and technologies at FreshDV.com.

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