Delivering video over the Web isn’t new, but it is for many producers. If you’ve viewed a lot of streamed content, you’ve seen the evidence—the blurry video, the muffled audio—but did you know that some of these poor projects might have been produced by professional videographers? Part of the problem is that the rules that apply to traditional video—and are followed religiously by some producers—don’t necessarily apply to Web video.
The differences between Web and traditional video start in the planning stage and continue beyond delivery. If you’re going to deliver on VHS tape, for example, you need only choose between NTSC and PAL. Producers of Web video have a number of things to consider before shooting, such as the audience’s Internet connections and media players.
First, outline your goals and think about your content. “A series of training videos we produced for a software company required large frame sizes to show an interface with small type and fine detail,” says Dale Sorenson, founder of Sorenson Services USA (www.sorenson-usa.com), a New York City provider of digital-video and streaming services and consulting. “We determined early on that it wasn’t possible to do so at dial-up bit rates. Luckily, we were able to assume the availability of broadband connections, and we delivered the project on CD-ROM. That way, the software interface was detailed enough to be effective.”
[an error occurred while processing this directive]
Once you know you’re shooting footage that will be shown online, there are certain steps you can take during the shoot that will not decrease your video’s effectiveness but will make the video more viewable as a stream. Start with the cleanest source possible, which means use a digital format such as DV or DVCAM. The fewer conversions and dubs you have to do, the less noise you’ll have in your Web video. Also, be sure your scenes are properly lit. “High-contrast lighting does not work well for video compression,” says Sorenson. “It requires higher bit rates, and if you don’t have those, your quality is compromised.”
Some of the most difficult-to-compress video is high-motion, so use a tripod. This is especially important for low-bandwidth delivery. “The camera should be stationary or mostly stationary,” says Sorenson. “You can do this without the video being desperately boring. Instead of doing a long, slow pan, do a quick pan. If you’re going to zoom, do it quickly and stop moving the camera so that the image can sharpen.”
Because motion consumes bandwidth, “make sure the things that consume bandwidth are the things you actually care about,” Sorenson suggests. For example, if your focal point is a car, but it’s parked in front of trees with leaves moving even slightly in the breeze, the leaves will monopolize the compression. Detailed clothing on your talent or a moving seascape background can pose the same problem.
Effects and transitions also affect your stream. A dissolve, for example, is a high-motion transition. “Every pixel changes in every frame,” Sorenson says. “It takes a lot of bits to encode a dissolve without it falling apart.” Instead, try straight cuts or wipes; the only pixels changing in a wipe are those along its edge.
Manic Compression
Many producers will show content in a tiny window and then beam about the smooth motion. But what good is smooth motion in such a small frame? Try halving the frame rate; you can double the pixels. “I often see video that’s not even 200 pixels across but has been encoded at 24 or 30 fps,” Sorenson says. “In most cases, you can get a better result by knocking the frame rate down to 15 fps. It still delivers smooth motion for most sources.”
Sorenson’s Web site includes several tools, including a bandwidth estimator that determines, in kilobits per second, how much bandwidth you will need based on your frame size and rate. Similarly, you can calculate your optimal frame rate if you know your bit rates and frame size.
Webcasting Call
If you’re planning a Webcast, first consider whether a Webcast is right in the first place. Are you conveying up-to-the-minute stock information or other truly time-sensitive messages? If not, consider video on demand. “Live Webcasting can undermine what makes Web video cool in the first place—that I can get it when I want it,” says Sorenson. He cites, as an example, a corporation that hired a hosting company to Webcast its CEO’s quarterly update. “The hosting company asked, ‘How much bandwidth do you expect you’ll need?’ and the client said, ‘We’re going to have 20,000 visitors.’ ”
The corporation also declined the offer to archive the Webcast. Luckily for the client, the hosting company did it anyway; only 200 people had tuned in. After that, the client agreed to make the archive viewable and, in that week, 15,000 people watched the address.
Another catch to Webcasts is that, because they are encoded in real time, the quality is lower than that of video on demand. “The compressors don’t have the luxury of spending more time to achieve higher quality,” Sorenson says.
Webcasts also suffer the same risks as live broadcasts. If there’s a problem with a camera, the lighting or the encoder, you can’t go back to fix it. “Even in a corporation, you might feel you have tons of bandwidth. But if 5,000 people tune into a broadband stream at the same time, you can sink even a major network,” says Sorenson. Consider a simulated live Webcast: capture your video, make adjustments, do a high-quality encode, then schedule the delivery.
“You don’t have to settle for boring, stationary, undetailed video on the Web,” Sorenson says. “You can break the rules, but before that, you have to understand what they are.”
[an error occurred while processing this directive]
