Editing HDV for TV

Using Avid Xpress Pro HD on a laptop —- plus an off-the-shelf USB 2.0 storage drive —- a veteran field producer readies HDV footage for prime time.

Art Donahue, a veteran field producer and photographer at WCVB-TV, the ABC affiliate in Boston, is well known throughout the New England production community for his 18 years of documentary-style TV reporting and his use of new technology to tell unique stories. He began producing segments for WCVB’s highly rated Chronicle series in 1987 with an Ikegami 79D camera and 3/4-inch VTRs. Since 1999, Donahue has produced more than 22 shows in HD for WCVB, the first in the Boston market to broadcast a digital HDTV signal. Two were shot with a full-sized Panasonic DVCPRO HD camera, two with Sony 1080i HDCAM camcorders and more than 20 shows with an Ikegami V90 with a DVCPRO HD back.

So When The Sony HDR-FX1 Came Out In November Of 2004 And WCVB’s owner Hearst-Argyle bought a few of the first ones, Donahue jumped at the chance to put the new compressed format to the broadcast test. "I was one of the first to get one," he says. "When something new comes along, I usually get a hold of it and see if I can produce a whole half hour with it," says Donahue. A veritable one-man-band, he’s one of the few producers at WCVB who writes, produces and edits his own segments. He’s been doing it that way for 17 years.

He has since upgraded to the Sony HVR-Z1U for its XLR audio connections, gamma setup and underscan Allscan mode in the viewfinder and now exclusively uses the Z1U on all of his high-definition shoots. But beyond taking the new camera with him in the field, he also wanted to take the paradigm one step further and edit an entire program on his laptop with off-the-shelf storage drives, without using the station’s more expensive online equipment. Last fall, to capture the beautiful foliage season of the Northeast, Donahue produced a segment with HDV equipment for Chronicle called "New England’s National Forests," which aired Monday, November 28, 2005. Thanks to its stunning and colorful vistas— which got a huge boost from color-correction, native HDV editing and clean, crisp effects in Avid Xpress Pro HD— received rave reviews from area viewers. Although several high-profile shows have used the 25 Mbps format for cut-ins and POV segments, Donahue is one of the first in broadcast TV to use it for an entire show. "It became a challenge to see if I could do it," he says, "especially since it had never been done before."

1080i, With a USB 2.0 Twist

All of the HDV footage Donahue shot over nine days for the program was cut on a Dell M70 laptop running Avid Technology’s Xpress Pro HD. The entire process for a typical Chronicle show, which includes three taped segments and live-to-tape studio bumpers, usually takes five weeks from start to finish.

After the footage was captured in the 1080i HDV format, the show was transcoded at the station to air in 720p, the ABC network’s HD format of choice. The 25-year-old Chronicle series still typically airs in SD, but once every five weeks the show is simulcast in "letterboxed" SD (4:3 aspect ratio) for NTSC viewers and full 16:9 720p for those with HDTV sets. This frees Donahue considerably in the field, since he can shoot for widescreen without having to protect his framing for NTSC viewers. "Not having to protect for 4:3 viewers is huge because that’s a big compromise to make when shooting outdoor scenes," he says. "I’ve shot some things where we had to frame for 4:3 and it’s always frustrating because you can’t use those edges [of the screen]."

Chronicle is supported by 12 other producers, three photographers and three editors. But because Donahue works alone, the final master audio mix is mono. Sometimes he uses a lavaliere or shotgun mic for on-screen subjects, but including digital stereo to the mix would necessitate a separate audio engineer in the field and add another week to the production process, he says.

WCVB’s 1080i HD workflow was developed well before the availability of 720p production equipment. Donahue said the HD format conversion process, using Panasonic conversion equipment, does not degrade the image quality and, in some cases, can actually produce better 720p images than those acquired with a native 720p camera.

For most of its other HD Chronicle shows, the station uses three Ikegami V90 cameras with DVCPRO HD dockable recorders. Since 2002, all WCVB HD shows have been shot in 1080i, downconverted to an SD FireWire stream, then offlined on a laptop with Avid’s Xpress Pro system. The completed show is then formatted as an AAF file and conformed in HD on an Avid DS Nitris system.

Converting the hours of HD field images to SD for editing, Donahue says, was his only option under deadline. "Because we shot ten hours or more of field material, it was basically the only way we could do it," he says. "Compressing all of that footage would take forever. We only have about 40 minutes of uncompressed HD storage with our Avid DS, and that’s not nearly enough to cut a whole show."

To gain more storage space, Donahue used an external Maxtor 300 GB USB 2.0 drive, giving him over 24 hours of HDV storage. He digitized the footage using a FireWire cable out of the camera, into the laptop, then sent the images out of the laptop to the USB 2.0 drive. Would it work? He wasn’t sure; no one that he knew had ever tried it before.

The system never dropped a frame and Donahue was able to render effects and even the entire HDV stream to the Maxtor drive-and play it off the drive back into the camera. To his surprise, file transfer times with USB 2.0 were performed just as fast as with a FireWire connection. Even engineers at Avid, who hadn’t seen this done either, were impressed with the final results.

Into the Forest

For five weeks in October and November, Donahue went to the Green Mountains in Vermont and the White Mountains in New Hampshire to shoot more than 10 hours of tapes for the 30-minute "New England’s National Forests," which highlights New England’s National Parks in all of their fall grandeur. The HDV-only segment also coincided with the 100th anniversary of the National Forest System.

He edited the entire project on his laptop at home. Though he originally intended to use the Ikegami V90 for most of the show— and only insert small HDV segments for POV shots he fell hard for the Sony FX1 and was eager to shoot an entire show with it. Since then, Donahue figures he’s put more than 300 consumer-grade tapes through the camera and says he saw only three dropouts. The camera itself has performed flawlessly.

While all the footage shot with the FX1 was kept in the HD domain for the entire post process, some archival SD footage was upconverted to HDV within the Avid Xpress Pro HD software. In total, Donahue says the piece included more than 400 effects, color corrections, matte keys, titles and credit rolls. The extensive amount of color correction, completed in Xpress Pro HD, was necessary, he says, because last year’s particular weather conditions prevented the fall foliage from being as brilliant as it was in years past.

" Chronicle is the ideal magazine-style show to experiment with new technology in order to tell better stories," he says. WCVB, he adds, is also committed to the high-definition format and is actively trying to promote HD programming to its viewers with colorful outdoor scenes and sporting events. Since 2001, during fall foliage season, Donahue has shot three HD programs a year. He rolls tape from the time when the first leaf turns color to when the last leaf falls to the ground, he jokes.

Native HDV Editing

Donahue says he was ready to start editing in HDV about six months before Avid actually came out with native HDV support on its Xpress Pro HD system. This native support, available since October 2005 in version 5.2.1, lets editors using Xpress Pro avoid cross-converting a clip to make it readable by the nonlinear edit system before work can begin. Donahue was an early beta tester (one of the first, in fact) of the new software, which he says worked great from the start.

Many people have argued that clean effects are impossible to create with HDV footage. Donahue agrees that any time you’re working with a dissolve in HDV, it starts to "block up" and break apart. But he says that improvements to the new version of Xpress Pro HD have helped change that misconception. When bumping up HDV images to Avid’s DNxHD codec— included with the new Xpress Pro HD software, it uses less compression than the HDV format itself— there are no such nasty artifacts, since the codec enables images to be rendered at 145 Mbps instead of HDV’s native 25 Mbps.

Donahue found another advantage to using the codec: He was able to output the show as an HDV MPEG-2 stream to a standard DVD for review by others at the station. Bear in mind, however, that the image files must be downloaded to a laptop’s hard drive for viewing in the latest version of Windows Media 9 or Nero’s Showtime 2. A typical DVD player doesn’t spin a disc fast enough to play back 25 Mbps material.

But on his laptop and on station monitors, the pristine quality of the images held their own. "When you see HDV images compressed with the DNxHD codec, you’re just blown away by he quality," Donahue says. If you look closely, he adds, there are some very subtle motion artifacts still visible. "Virtually nothing is lost from the original tape. Anytime you’re adding with video effects, the DNx codec renders it with less compression, so it looks great. This really surprised me."

Xpress Pro HD color-correction tools also helped him temper an unwanted haze in the skyline or a less-than-colorful fall leaf. "My job is to tell interesting stories, but also to experiment with the gear and see if I can actually pull off an entire show," he says. "I was able to complete everything, from first frame to final frame, in Xpress Pro HD, without compromise. Every aspect of what I used to do with the Avid DS Nitris system I can now do in Xpress Pro HD. It’s really quite amazing how far desktop editing technology has come. I’m now producing broadcast-quality programming on a laptop with a $3,500 camera, a $2,000 laptop and $1,500 software."

Bumpers and All

Production and post for a complete show takes Donahue about five weeks. After two weeks for a full shoot, he says, writing the script and digitizing the ten hours of videotape and associated audio tracks usually takes him about a week. He then will offline the show (the same as he does with an SD show). The fifth week is used to rebuild the show in HD and add effects. Donahue says he will occasionally digitize footage in the field, but typically does all his editing at home on his laptop. He does final dubs, however, to DVCPRO HD on WCVB’s Avid DS Nitris.

The finished show is output as an MPEG-2 HDV stream from the laptop as an.m2t file, which is recorded onto a master HDV tape, copied to a DVCPRO HD tape, then fed into an Avid DS Nitris system for finishing. The show is converted to 720p with a Panasonic DVCPRO HD deck and played to air from two Panasonic D-5 VTRs, rolled simultaneously for redundancy. The SD version is downconverted from the D-5 tape and sent to air live from the dual decks.

Because the station does not have HD cameras in the studio, Donahue has to tape his program bumpers in the field. This requires more shooting than a typical SD program and, unfortunately, more time. But he says he actually prefers to shoot these segments in the field because of the more optimal lighting conditions.

"HD cameras, in general, are not as sensitive to low light as SD cameras are," he says, "so if I go inside with my HDV camera, I’m putting lights up all over the place. You really can’t kick up the gain in HD without causing other image problems. Shooting HD is sometimes a slower process."

Anywhere Editing

Donahue has now completed eight Chronicle shows with the Sony HDV camcorders (six dubbed to DVCPRO HD for editing on a DS Nitris system and two edited with native HDV in Xpress Pro HD).

He also recently completed work on another HDV segment for Chronicle that focuses on the explosion of digital photography among consumers. [More than 50 percent of Americans now take pictures with a digital camera instead of a film-based camera.] "This HDV workflow has saved me a considerable amount of conform time and color correction," Donahue says. "For a person who works alone, as I often do, this way of working is fabulous. You could be in a hotel room anywhere in the world and edit an entire HD program for broadcast. That’s compelling to everyone in this business."

Nitpickers might argue about the image resolution of an HDV program, but Donahue challenges them to create a program of the quality of the Chronicle series in less time and with less hassle. To him, under today’s fast turnaround production cycles and often challenging work conditions, there’s no comparison.