Editing in 24p - TvTechnology

Editing in 24p

There is a new dance being done in Hollywood postproduction circles these days. It’s called 24p, and as the name implies it rocks to a different cadence than the 30-frame-per-second video waltz to which we’ve been trotting since subcarrier replaced bobby soxes.
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There is a new dance being done in Hollywood postproduction circles these days. It’s called 24p, and as the name implies it rocks to a different cadence than the 30-frame-per-second video waltz to which we’ve been trotting since subcarrier replaced bobby soxes. To learn the steps, one of the hottest tickets in town for a rollicking evening of swinging entertainment has been invitation-only attendance at a whole slew of seminars various postproduction facilities have been hosting to introduce what many hope is the solution to the quagmire of proliferating international high-definition formats.

As its name implies, 24p is a new recording format that lays down 24 frames per second, with each frame recorded progressively, as opposed to the 2-field/frame interlace process we’ve grown to know and love in the NTSC/60I environment. Because most primetime television is still originated on 24 fps film, a 24p video format provides a one-to-one relationship to its celluloid antecedents and in addition to TV broadcasting lends itself directly to digital cinema applications.

In addition, Sony Electronics released the new CineAlta high-definition production systems late last spring to shoot 24p high-definition video in the field and postproduce it in its original 24 frames-per-second sequence. Sony has had 30 fps high-definition production equipment for several years, but by adding an "F" (for "film") in front of the model numbers the company is touting the fact that the new CineAlta line is geared for 24 fps acquisition and finishing.

This includes the HDW-F900 high-def camcorder and the HDW-F500 digital VTR. Although everyone is talking about how George Lucas recently completed principal production on the second episode of his "Star Wars" epic using a CineAlta camera with specially designed Panavision lenses, several other 24p productions have already benefited from the CineAlta process.

EASY CONVERSION

Perhaps even more importantly, since a 24 fps video cycle translates efficiently into the 50 hz formats used around the world, 24p recordings are easier to convert to the Babel-busting basket of video flavors that people outside North America have adopted. As a result, 24p offers the inducement of a universal mastering intermediary out of which all of today’s video productions can be translated to keep them safely available for whatever delivery format today’s content creators will want to make available to future market distributors.

So how will 24p affect editors? There aren’t a lot of digicutters out there who have actually edited high-definition productions yet, but one with as much experience as most is Anita Brandt Burgoyne A. C. E. who has completed "Skeletons in the Closet" with Treat Williams in a 30 fps HDCAM to be released from Artisan Entertainment sometime this summer, and is now editing the MGM feature "Legally Blonde," starring Reese Witherspoon, which was shot in 24p.

Burgoyne laughs that she started on a moviola and is now editing high-definition on an Avid Film Composer. What new challenges has high-def given her?

"Actually, not very much in terms of what I do technically," she says. "Once the 30 fps "Skeletons" HD video project was digitized into my Avid, it looked different than a 24 fps film-originated shoot and it took me a couple of days to get used to it. Other than that, I cut it the same way I deal with a film production once my assistant, Darrel Drinkard, had digitized it into the system at Digital Cut Post in Culver City," says Burgoyne.

Drinkard had to sync the dailies in the Avid because there was no window burned timecode on the dailies, according to Burgoyne. "This is a new process, and the telecine technician who did the transfer on the set tried to tell us the SMPTE code was invisible. We found out that was not the case, but it was just a result of being one of the first to deal with HDTV in post."

LEGALLY BLONDE

The 24p-originated "Legally Blonde" did, however offer some new experiences. "After we have edited it, the difference will come in how we go through the audience preview process," says Burgoyne. "This is the first time we will preview it before test audiences in HDTV in a way similar to the way we present TV movies," Burgoyne tells us. "We won’t conform a workprint, but will autoconform a high-definition master for the digital cinema screenings and then make changes based on the audience’s response to the ‘film’ using video technology. Other than that, we have been editing widescreen feature films shot at 24 fps for a long time – so if with an assistant as good as mine on this project, Alex Renskoff, the editor’s job cutting 24p is pretty much the same."

WHOLE NEW TECHNOLOGY

However, when a 24p project goes to online a whole new technology has to be called upon. One of the pioneers in 24p finishing is The Post Group in Hollywood, Calif., where the company has a high-definition online bay built around an Axial 3000 linear edit controller, a Snell&Willcox HD1010 switcher, a HD Deko 500 character generator, a Graham Patton DSAM audio mixer, and both Sony HDW-F500 HDCAM and Panasonic AJ-HD3700 D-5 high-definition VTRs.

The Post Group’s on-staff high-def online editor is Bobby Gutierrez, who already has two 24p projects under his belt: the CBS mini series "Jackie Bouvier Kennedy Onnasis" and "Jackpot," an independent feature produced by The Polish Brothers of "Twin Fall, Idaho" fame.

Gutierrez explains that because the offline cut is output onto a 30 fps tape because there are no inexpensive 24 fps video recorders available, the first issue is to deal with is the 3/2 pulldown that lets 24 fps source material reside on 30 fps video.

"We upconverted the 30 fps offline master to 24 fps to lay down on our final record master as a reference," Gutierrez begins. "If the 3/2 pulldown is not handled correctly, you get a ghosting effect from the jitter frame generated by the 30/24 fps conversion. We ran into this on the ‘Jackie BKO’ HD project, but luckily it was during a sequence originated on Super 8mm to simulate home movies and we were able to solve it by softening the image. But in other cases we had to have the material upconverted again to fix 3/2 discrepancies."

SIZE MATTERS

Gutierrez next had to deal with the fact that the widescreen aspect ratio of HDTV has to be composed with an eventually re-purposed 4:3 image size in mind. To satisfy this he called upon the DVE built into the Snell&Willcox HD1010 switcher.

"We overlay a 4:3 reticule, or grid, over the image and made sure everything was in a safe area in the preview mode. As it turned out, we started out with the wrong reticule and some of the credits were truncated out of the title safe area of the square image. These had to be redone."

Audio sync also proved to be a problem. "Our facility is 90 percent set up for 30 fps playback, and the audio from the 24p masters tended to drift occasionally," Gutierrez recalls. "The only way our engineering staff could get it to work reliably was to first lay the sound off onto DigiBeta tapes and reprocess it in the 24 fps realm to keep it in sync. Our engineers were working in new territory and came up with very creative solutions."

SOME QUIRKS

Even something as superficially simple as downconverting 3/4-inch U-matic dubs for audio sweetening produced some quirks. "The dubs were supposed to have two timecode windows, one running at 30 fps, the other at 24 fps.," Gutierrez says. "It was difficult to tell which was just out of sync vs. the material that was dubbed in during ADR (Automatic Dialog Replacement) sessions. Once you start mixing timecode rates, things can get sort of rubbery. Sliding back and forth between the two frame rates caused sync issues but, once again, our audio engineering staff found a solution by laying back the sound."

Converting the EDL from offline to online proved to be fairly simple, however, thanks to The Post Group’s Avid Symphony system. "With Symphony’s EDL Manager feature, the number crunching proved to be very simple," Gutierrez says. "That is a technology that Avid has worked out in a way we can rely on. Before I covered the low-res offline reference tape with HD images, I chose six edits randomly on the timeline – two at the beginning, two in the middle, and two at the end – and checked that the actual frames were accurately represented in the EDL."

According to Gutierrez, things can get pretty complicated as editors and their support staff wrestle with the unknown territory of 24p high-definition production. "Remember, all these hurdles were overcome just to get me started in the online process," Gutierrez says. "It opens up a whole new set of challenges for editors to overcome."