Webcasting DJTV
by The Editors
Here at Digital Juice we've been posting video to the Internet as long as we've had a Web presence. The play-in-place samples of our product galleries and our promotional videos illustrate two approaches that we've tried in the past. Our new DJTV project, however, required a complete rethinking of our video strategy, not only in terms of content, but also in terms of technical delivery. In this article, we're going to tell you how we prep our shows to get them on the virtual airwaves of the Web.
PRODUCTION
The mission of DJTV is to create short shows that effectively inform, instruct and (hopefully) entertain the production community on a wide variety of topics. Because the video is primarily distributed on the Internet, we need small, highly compressed clips, but one goal right from the start was to shoot in the highest quality format that was practical.
"We went with our Panasonic HVX200 in 720p HD mode at 24fps," explained Senior Producer, Perry Jenkins. "The camera's small size and convenient operation made it possible for all of our producers to jump right in and start shooting."
The finished video that the production department provides to the Web team is very high quality, uncompressed, progressive HD source.
COMPRESSION GURUS
The task of getting DJTV onto the digitaljuice.com Website falls to IT Director, Michael Mullings, and Director of Internet Development, J.P. Shook. Each wears many hats at the company, but both are well versed in the many challenges of Internet video.
"All of our promo videos were compressed using Sorenson Squeeze 3 on a five PC farm," explains Mike Mullings. "It's a great app. The Watch Folders feature was really convenient." Five dedicated Windows computers were set up to perform the renders, with the Sorenson utility watching a particular folder that producers could drop their finished video into. The program would then automatically convert the videos placed into that folder without any additional intervention.
H.264 QUALITY
The Sorenson Video 3 Pro codec produced beautiful video for the Internet, but the Web/IT team decided to go with the next generation of video for DJTV. A number of solutions were explored, including one based on the H.264 standard, which has been implemented (with variations) by most of the big players, including Apple and Sorenson. Test renders using Apple Compressor and Sorenson Squeeze 4 proved that the H.264 codecs yielded better quality video than the older Sorenson Video 3 Pro codec. "For DJTV, we felt that it was important to deliver the highest quality video at the lowest possible data rates," J.P. Shook said.
The one format that seemed to best meet our DJTV requirements was the QuickTime implementation of the H.264 codec. While not universally installed, the QuickTime player is on all Macs and has a very wide install base on Windows machines. While QuickTime is very common, not everyone has the latest (May 2005) version of QuickTime 7, which supports H.264. "To be honest," J.P. admitted. "One of the reasons why we went with QuickTime 7 H.264 was that many studios use it for their movie trailers."
ACCESSIBILITY
Besides balancing quality against data rate, DJTV needs to be viewable by the largest possible audience. So, for example, while DivX produces very high quality video, it is still a player that is not installed on as many computers as, say, the Flash video player. Flash video, on the other hand, although it does keep the data rate very low, does not hit the same quality levels that Sorenson Video 3 Pro does. To keep DJTV accessible to largest possible audience, the team chose to encode the medium- and low-quality versions of each show using Sorenson Video 3. Since this format is compatible with QuickTime 5 and above, almost everyone can play it back. And, not unimportantly, the quality is excellent.
SOURCE AND SIZE
Another consideration in the choice of a file format and codec is scalability. At this time in Web video history, it's important to offer different versions of our videos, from small and highly compressed to very large at high quality. H.264 encoding works equally well on postage-stamp sized video destined for portable players and on HD video for blue laser DVDs.
The source for DJTV is 720p, which has a frame size of 1440x720. A number of different versions of each program segment are available to view or download, including 480x288, 320x192, and 320x240 for iPod. "We wanted to reach the largest audience possible," J.P. continued. "Encoding multiple formats is a real challenge, but definitely worth it."
Broadband Distribution and Streaming Broadband infrastructure in the United States is getting better and better, but simply posting DJTV segments to a Web page is not enough. You also need the computers and Internet bandwidth to host and serve the content. "With multiple dedicated load-balanced Web servers connected to the global Internet backbone, we have the capability to sustain over 200Mbps of concurrent traffic." J.P. noted. "We expected to exceed 4TB of data transfer in the first month of the DJTV launch."
Real-time streaming video was one option that was considered and eventually rejected. "We decided to go with progressive download vs. real-time streaming servers to maintain the highest level of quality and user experience," J.P. mused. "The performance is excellent and the videos begin playing almost immediately." Streaming technology can also prevent people from downloading the video to their computer, which is an unnecessary limitation and an inconvenience for some viewers.
EACH EPISODE OF DJTV IS OFFERED AT FOUR QUALITY SETTINGS
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(1) 480x288 - High Quality (H.264)
(2) 320x192 - Medium Quality (Sorenson)
(3) 320x192 - Low Quality (Sorenson)
(4) 320x240 - iPod (MPEG-4) |
READY FOR WEBCAST
Even though the technology is readily available, making a choice on how to distribute high-quality video on the Internet is not an easy one. Besides balancing quality against data rate, compatibility and convenience are difficult quantities to measure. Fortunately, given a fast enough Internet pipeline, experimentation is relatively easy. Even better, the potential audience of Web viewers is huge and growing larger by the day.
The Editors
| Although the technical spec for H.264 is as complex and detailed as it needs to be, it's really just geeky jargon for MPEG-4. Born of a partnership between the ITU-T Video Coding Experts Group and the ISO/IEC Moving Picture Experts Group (MPEG), the H.264 standard and the MPEG-4, part 10 standard are technically identical. And if you don't like calling the standard H.264 or MPEG-4, you can go ahead and call it Advanced Video Coding (AVC): it's all the same thing. |
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Want to find out more about the encoding apps we use for DJTV?
 Apple Compressor is a part of the Final Cut Studio suite of applications for the Mac and has an MSRP of $1,299. http://www.apple.com
The Sorenson Video 3 Pro codec has an MSRP of $299 and works with your editing software, but is also included with the Sorenson Video 4 Compression Suite, which retails for $449 and works on both Windows machines and Macs.
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