Tackling HDV Editing: At the Starting Gate

HDV was one of the hits of NAB2005. Now, as the dust is starting to settle, trying to survey the spectrum of how major editing manufacturers are tackling the challenge of posting that long-GOP (group of pictures) format is almost as daunting as squeezing a massive high-definition recording onto a tiny DV tape.

HDV was one of the hits of NAB2005. Now, as the dust is starting to settle, trying to survey the spectrum of how major editing manufacturers are tackling the challenge of posting that long-GOP (group of pictures) format is almost as daunting as squeezing a massive high-definition recording onto a tiny DV tape.

So, for efficiency, this column has asked representatives of the various players to describe the specific approaches their systems are taking toward editing HDV and what they consider to be its advantages.

First off, HDV is actually an MPEG-2 recording format that currently comes in two flavors--progressive (HDV 1) or interlaced (HDV 2). Recording 720p onto tape, JVC was the first to ship a pro-level HDV camcorder in 2003, the JY-HD10U, and this year topped it with the more advanced 3-CCD GY-HD100U with interchangeable lenses.

"We don't say progressive is necessarily better than interlaced," said Dave Walton, communications marketing manager at JVC. "But we feel scanning the CCDs progressively does give you a more cinematic look. You can also get better freeze frames without motion displacement, and it is more compatible with most progressive HD display devices. Our cameras are targeted at the emerging digital cinematography market but, of course, progressive recordings can easily be converted to interlaced."

Sony, on the other hand, has opted for 1080i recordings in its camcorders, which has come to be dubbed "HDV 2" and was originally introduced in its consumer camcorders.

As a result, "the obvious recording choice for the two professional Sony versions of HDV camcorders, the HVR-Z1U and the new HVR-A1U, was 1080i," said Bob Ott, vice president of Sony Electronics professional video and audio products. "This decision provides professional users with an easy transfer path to existing Sony professional HD equipment at a very cost-effective price."


But how do you post this new form of low-cost high-definition recording? As we'll see, some cut it in HDV's native long-GOP format, some transcode it in intraframe (I-frame only) file style, some bump it up to uncompressed HD, and others are, well, waiting until they feel they can get it right.

Pinnacle Systems was the first to demonstrate editing HDV at NAB2004.

"We can do all our real-time effects with multiple streams of HDV at full quality," said Jim Thill, product manager for Liquid Edition at Pinnacle. "With our new Version 6.1 software released this year, we do some serious math using a combination of a DirectX 9 graphics card's GPU and the CPU's own processing to let us handle up to four layers of HDV in real time. The expanded HDV capabilities of Pinnacle Liquid Edition 6.1 provide an end-to-end workflow including a full-screen preview of the editing timeline for all formats."

At NAB2005, Apple brought out Final Cut Pro 5 software that can also edit HDV natively.

"We called upon our own codec team at Apple to 're-plumb' the architecture of QuickTime 7 inside Final Cut Pro 5 to handle native HDV files," said Kirk Paulsen, Apple senior director of professional applications marketing. "To maintain the 15-frame GOP cadence, we decompress and re-construct its structure at the cutpoint in the native HDV codec without going to an intermediate format. Our tests show this approach lets us maintain the 8-bit luminance values of HDV without significant pixel value errors measured as PSNR [peak signal-to-noise ratio], resulting in an average luminance shift of only 1.6 out of 256 luminance values even after five generations."

Adobe Systems is taking a different approach with its Premiere Pro 1.5 editing software. Richard Townhill, group product manager at Adobe Digital Video and Audio said

any Premiere Pro editor could download a free HDV plug-in at www.adobe.com/products/premiere/hdv.

html since Version 1.5 was released before all HDV formats were available.

"We transcode HDV during capture to a wavelet file format that Adobe has licensed from Cineform which, in addition to giving us a two-frame GOP for improved editing performance, converts the 4:2:0 color space of native HDV into full 4:2:2, which we feel gives us improved compositing and effects capabilities without losing color definition."

Sony Vegas 6 software can go either way by cutting HDV off tape natively, or, as Dave Chaimson, vice president of marketing at Sony Media Software, recommends, transcoding it into an AVI file format through the Cineform codec built into the Vegas application.

"The AVI files let you edit much faster, even though they increase storage requirements," Chaimson said, "but of course the transport stream gets recompressed to MPEG-2 upon output. We feel the intermediate codec provides a better editing experience and more precise editing control of any HDV recordings, and lets you get this performance even when using relatively slower platforms like laptops."

With its new Edius Pro 3 software, Canopus has another option for transcoding HDV during editing.


"You can bring in the HDV data directly on a system with OHCI [Open Host Controller Interface] over FireWire," said Brandon Higa, senior marketing engineer for Canopus. "Or you can use it in conjunction with our Edius NX for HDV or Edius SP for HDV hardware cards in our board-and-software sets, or our Edius SD or Edius HD turnkey systems, all of which convert 720p HDV into 1080i on the fly. But the key Canopus advantage is our Canopus HQ codec that converts the MPEG-2 transport stream into our own format of AVI files on your hard drive. This intraframe compression format is easier for your CPU to decompress, giving you four streams of HQ video, and it provides the 4:2:2 color space for improved layering and effects. We feel the variable bit-rate Canopus HQ codec also delivers better image quality when going to an analog output."

In June, Leitch Technology released one of the latest entries into HDV editing with its new 9.1 software for its VelocityHD nonlinear edit system.

"We've chosen to transcode HDV during real-time ingest into our LWC-1 compression format," said Mike Nann, product marketing manager, post-production editing at Leitch. "Our full raster, variable bit-rate LWC-1 format is our own style of wavelet compression and uses an intraframe structure which is much easier and faster for editing than interframe long GOP. In our mind, HDV is just one of the high-definition formats our VelocityHD customers will want to work with on the same timeline, maintaining all the real-time capabilities they have come to expect"

Specializing in the highest end of post production, the folks at Quantel are handling HDV the easy way. They simply bump HDV up to

an uncompressed baseband format and post it as they would any other HD signal.

"Quantel's attitude to HDV is that we very much welcome everything that will move our world more rapidly towards HD, and HDV is definitely a bridge to that," said Steve Owen, post DI marketing manager for Quantel. "Even if its application at the higher end of post would inevitably be somewhat limited due to HDV's highly compressed nature."

Finally, even though Avid did not present shipping HDV editing capabilities at NAB2005, their market position justifies being included here.

"We have been demonstrating native HDV editing in our roadshows, and will have a beta release this summer," said David Schleifer, vice president of broadcast and workgroups for Avid. "We want to work out all the kinks so people will have the smooth workflow with HDV that they expect from our NLEs. When we ship our native HDV editing solution in Q4, it will be another resolution in our timeline that editors can mix and match with the same feel of all the other formats."