Whether You Transcode or Go Native, Your Editing Options Have Multiplied
Chat with an NLE provider these days, and the subject quickly turns to HDV. Just as the HDV format helped catalyze a burst of innovation in the camera market, it continues to demand creativity on the part of software and hardware engineers who have to make it viable in the editing suite. That's a tricky proposition for engineers – and it's not exactly straightforward for users.
Different editing systems are tackling the problem in different ways, ranging from native support of the HDV codec to an automatic transcode into a one-size-fits-all codec for HD material. Different codecs maintain the image at different resolutions. And sometimes you have a choice of different HDV workflows within the same editing program. Here’s a look at how some of it works.
The HDV Specialists
The companies with the longest specialized pedigree in HDV are probably Lumiere HD and CineForm, both of whom have been widgeting HDV footage into existing post workflows since the first HDV cameras hit the market. Lumiere HD works with Final Cut Pro to input, output and manipulate the MPEG-2 transport stream inside that program, and CineForm serves a similar function in Adobe Premiere and Sony Vegas on the PC.
Just a few months ago, Lumiere’s Frederic Haubrich saw the writing on the wall: Apple was adding native HDV support to Final Cut Pro, and it looked like the days of Lumiere HD’s viability as a separate product were numbered. These days, however, he’s working on Lumiere HD v2 in between sessions finishing his HDV-shot feature film, Tomorrow Is Today. What are the enduring issues? For one thing, Final Cut Pro does not yet support HDV editing in 24p mode- the main selling point of the new HD100U. Haubrich thinks he can fix that.
In addition to 24p support, Lumiere HD 2.0 is going to represent a rethink of HDV workflow, Haubrich explains. "HDV is a decent codec for acquisition, but even though Final Cut Pro does an amazing job with native HDV, [the codec] tends to fall apart as soon as you start doing compositing and layering and color-correction. So we’re looking for the best option to go to an alternative codec before you do final renders or color-correction," he says. That means Haubrich is out looking for hotshot video codecs that might be incorporated in the revision, which should be available by the time you read this. The application will probably be split into three pieces: one for ingesting HDV, one for encoding a transport stream (for recording out to D-VHS, for example), and another for batch-transcoding from HDV to another format. It also will not be locked down to Final Cut Pro.
CineForm, meanwhile, is making a reputation with two different flavors of HDV support. Aspect HD and Connect HD work with Adobe Premiere Pro and Sony Vegas (and other AVI-compatible apps), respectively. When you use one of them, your HDV footage is transcoded to CineForm’s intermediary codec, which supports HDV’s native 1440×1080 resolution at 8 bits. CineForm’s David Taylor suspects that quality level is adequate for "perhaps 90 percent" of HDV projects.
For the other 10 percent- maybe a project that mixes 1920×1080 4:2:2 footage from an F900 with 1440×1080 4:2:0 HDV footage- CineForm’s Prospect HD offers a full-raster 1920×1080 10-bit workflow that upconverts the HDV footage to match the higher-resolution footage. Quality freaks may want to use the high-resolution Prospect HD workflow anyway, even if they’re only editing HDV. "If you have heavy multi-generation requirements, then even though the source precision is only 8 bits, utilizing a 10-bit workflow during post can guarantee additional visual quality," Taylor explains. Both Aspect HD and Prospect HD support JVC’s ProHD 24p camera.
Significantly, CineForm hasn’t settled yet. There’s a new implementation of its technology, called Prospect 2K, that kicks resolution up to 2048×1556 for full-sized feature-film applications. An animated Imax movie called Santa Versus the Snowman was recently re-edited at 2048×1550 using Prospect 2K, and the cut Super 16 negative for a new project called Lbs was scanned directly into the CineForm Intermediate format at 2048×1276. Look for CineForm to make more inroads into full-scale DIs in the coming months.
The Case For Native Editing
But support for editing HDV in its native format is gaining currency in the NLE world, especially among vendors who say any quality hit during image processing is minor. "You will never do repeated re-encodes in Final Cut Pro," says Paul Saccone, Apple’s product manager for Final Cut Studio. "If you take an HDV stream, whether you’re doing color-correction or a 16-layer composite, we decompress all that video into a 4:4:4 color space, do our composites, and then do one single re-encode back down to the HDV format. So you’re only, ever, incurring one generation of re-encoding."
Pinnacle’s Liquid products have been handling HDV natively- including 720p from the JVC HD100U- since early last year. "The definite benefits of native are retaining quality, retaining structure [of the MPEG-2 data], not wasting time to make transcodes, and not wasting space to save multiple versions of the same product," says Pinnacle’s Andrew Baum, who recently moved from the pro to the consumer side of the business- starting this month, native HDV is supported in Pinnacle’s $99 consumer NLE.
At Avid, native HDV support is coming soon- it should be a reality by mid-October. "If you look at our overall strategy, we support a lot of codecs in their native forms," explains Avid product marketing manager Matt Allard. "We manage those files in a very transparent way for customers, to and from devices. And for customers who are doing simple-cuts editing, that’s the best way to deal with the media. But we recognize that sometimes you’re doing things that require more processing – color correction, graphics and compositing – and once you enter that realm, you want to look past acquisition codecs to codecs that are built to stand up to what happens in post-production when you start processing pixels or combining them with other formats."
For Avid, that tough codec is, of course, DNxHD, a compressed HD format (running at up to 1920×1080 10-bit) that’s designed with advantages over in-camera acquisition codecs. "Your footage is always in the native raster of the HD format you’re dealing with- you’re not trying to scale up and scale down the resolution for editing or effects, which can be destructive to image quality," he says.
But he’s also quick to defend Avid’s handling of HDV footage in its native form. "One of the cool things about Avid’s editorial products is the open timeline, which allows you to mix resolutions, putting HDV next to uncompressed HD next to HDCAM. In other products, you have to render all but one of them. DNxHD can be an important part of the process, but if you don’t want to use it, your Avid will be very careful with your footage."
Mix and Match
Leitch sees a similar trend toward mixing and matching formats among its own HDV users. "HDV is just one of the formats they will be working with," says Mike Nann, Leitch’s technical marketing manager for post-production. "Often, HDV will be just the acquisition format, with final output aimed at a higher-end format, broadcast server, or other destination." VelocityHD transcodes HDV into Leitch’s own wavelet-based compression format, LWC-1.
That means HDV content is upscaled during ingest to the full 1920×1080 raster size used by LWC-1, which Nann says ensures that quality is maintained across all HD formats, but avoids the system slow-down you’d see if the scaling occurred during the editorial process. "Even in [other] systems that support the full 1920×1080 raster," he explains, "upscaling the 1440×1080 content on the fly during editing negatively impacts real-time performance."
Canopus has its own intermediary codec, Canopus HQ, which supports HDV in its native resolution, 1440×1080. Edius Pro 3 will let you work with an unaltered HDV transport stream, if you really want to, but performance will be sluggish. At IBC last month, Canopus announced a next-generation codec, HQ+, which will support the full 1920×1080 raster.
"We are, unfortunately, not yet well entrenched in the filmmaking market," admits senior marketing manager Brandon Higa. "We hope to be there, and this is one step forward in that direction."