Tutorial: Shooting Top-Quality Streaming Video Part II: Designing Your Set

我第一次涉足数字视频, 大约在1994年, went like this: I hired a professional crew to film a tutorial on video compression. The set they designed featured a rosewood desk against a gray fabric background decorated with plants, and graduated lighting accented with several spotlights. I wore a snazzy black blazer with little white flecks that looked better than it sounds. We shot in BetaSP, edited on 1" tape that I outputted onto a laserdisc for frame-by-frame capture. On the studio monitors, the video looked awesome.

We struck the set, and about a month later I compressed the video to Indeo 3.2的格式. The graduated lighting on the back wall created color bands that crawled in the background like dancing snakes, and the accent lights were blocky stabs of yellow. 我的外套也很糟糕, with most of the flecks gone and those that remained resembling giant dandruff flakes.

Though I compressed it with the best technology of the day, I couldn’t imagine selling the tutorial video and ultimately chose not to even try. The only return on my substantial investment was the searing lesson that backgrounds and 服装 really matter when it comes to compressed video quality.

In the fall of ’05, I started work on a research report for StreamingMedia.com that involved compressing approximately 42 business-, 行动——, and entertainment-oriented clips into various resolutions using Flash 8, H.264、Real和Windows Media. This added to my knowledge base regarding which types of backgrounds perform well under the strains of video compression and which don’t.

为了补充这项研究, I performed a quick-and-dirty survey of business-oriented video on the web, including national media sites like CNN, ESPN, 美国广播公司, 哥伦比亚广播公司, 当然还有高尔夫频道. Since these sites were all dual-use (TV and streaming), I also sought videos produced primarily for the web by companies such as RealNetworks, 微软, Akamai, 惠普(hewlett - packard), 德勤会计师事务所, 和普华永道. 我浏览了On2等其他网站, Adobe, and Apple for business-related content, but most showed only entertainment-related clips such as movie trailers that were clearly converted to, 不是为, 网络视频.

The web-only group led to two further groupings. The first comprised videos for which the companies designed backgrounds and 服装 solely for announcements and other streaming video. 例如, when RealNetworks’ Rob Glaser spoke during the introduction of an online training class, you can assume that the company selected the background, 服装, and lighting that would present the highest possible quality at the selected encoding parameters.

The second group was case studies, primarily produced by 惠普(hewlett - packard) and 微软. 在这里, part of the value of the content involved showing the clients in their environment, 而不是靠在蓝色的窗帘上, 然而有品味. Though it appears that HP and 微软 "encouraged" their participants to wear compression-friendly 服装, they also came up with compression-friendly backgrounds in a range of environments, 产生几个有趣的教训.

But let’s start with the basics, a high-level description of what the ideal background should do. First, it should provide contrast to help the viewer distinguish the talent from the background. This concern obviously relates to what the talent is wearing, which I’ll discuss below. 第二个, the background should be visually interesting, 或者至少很吸引人, with minimal detail to distract the viewer from the talent or make the file more challenging to compress.

不要使用的背景
It’s fairly simple to catalog a range of practices to avoid, from both my own tests and my informal survey. For the sake of brevity, I’ll include them in bullet form.

—Avoid solid backgrounds in red, white, and tan. Non-reflective black is the safest choice (except for H.264).
—Avoid fine details like those in bookshelves, fancy wallpaper, Venetian blinds, and the like.
—Avoid backlighting (windows, doors, other powerful light sources).
—Avoid background motion (waving trees, folks walking).
—Minimize open spaces in your background. As you can see from that fateful video from back in 1994, 后墙完全敞开着, leaving lots of room for compression artifacts to collect and become very obvious. Since then, my mantra has always been "clutter is good."