Compressing the Goods

Everybody’s doing it. Whether it’s for private e-mail to friends, or mass distribution, here are a few basics and then some for compressing video for the Web.

You have that great video finished, the one with your finest camerawork and editing, and you want to share it. Now what? Sure, you can make a few DVDs and hand them out. There’s certainly nothing wrong with giving the gift of a shiny spinning disc! But distributing and sharing video over the Web is no doubt creating excitement for a reason: it’s easy, it’s effective and it’s fun. Getting marginal results is the norm, but you, the Videomaker reader, want to do it better. You want your picture sharper and your sound clearer. Whether you simply want to share short videos with family, or you’d like to showcase HD video for your paying client, knowledge of video compression is important. So, if you’re not into video compression, you’re missing out!

Defining Compression

When we talk about compression, we typically mean reducing the file size of a piece of video. Compressing video means more than squishing a big picture into looking like a little one. And it’s more than taking that 5-gigabyte behemoth and turning it into a mere 50-megabyte video file. Compressing video also allows us to change the format of our video, from one that only we can watch into one that a wide audience can view. Consider trying to send an original HDV (or other high definition video) clip from your computer to a friend, over e-mail. Even if the video file is small enough to fit within your e-mail file size limitations, you may be putting your friend in a pickle. Not everyone has the ability to play back the HDV format video you’ve sent. Compress the same video into a more widely-used Windows Media or QuickTime format, and the odds are in favor of your friend. So let’s get started, shall we?

A Moving Target

Recent advances in video compression have redefined what “Web video” means. It used to mean squinting at a small, blocky window that barely played moving images. But viewers’ expectation of Web video has undergone radical changes lately. Most of this is due to better video compression technologies that supply viewers with higher-quality video. A recent advancement includes video compression using H.264, which dramatically changes the landscape of Web video, by allowing video to be compressed into ever-smaller files while maintaining higher resolution. Additionally, the H.264 codec has found its way into Adobe’s prolific Flash Video Player, making it a much more usable codec. As Internet connection speeds continue to increase all over the world, eventually the floodgates will be wide open for delivering high-quality video across the Internet.


Basic Ideas for the Home

For videographers who want to e-mail video and use online video-sharing sites such as YouTube, here are a few ideas for better video. While e-mailing video is private and as simple as attaching a photo, some hurdles are present. Current limitations include how much an e-mail account will allow you to send and which video formats the e-mail recipient may play back. Many e-mail accounts top out at 10 megabytes for attachments. Though it doesn’t seem like much at first, it’ll allow a couple minutes of compressed video, enough for a thoughtful video greeting card, the winning goal or a baby’s first steps. When compressing for e-mail, reducing the resolution in half helps keep the file size to a minimum. Use a resolution of 400×225 pixels for widescreen DV video, 320×240 pixels for standard DV video and 960×540 pixels for high-definition video. Keeping your video at 30fps (full-motion video) will create the smoothest motion. If you need to reduce the file size even more, reducing the frames-per-second will help tremendously, but you’ll want to use it as a last resort. As a general rule, cutting the videos frames-per-second in half, from 30 to 15fps, will reduce the file size in half as well. The resulting video may seem to stutter as it plays, but it may be the only way to send it as an attachment.

Web sites like YouTube offer unparalleled capabilities for sharing video with large numbers of people. If you want to send longer videos and to more people than you can access through e-mail, consider compressing for a video-sharing site. YouTube automatically compresses your video for playback on its Web site as Flash video. Your video must be under 100MB, though, which means you’ll have to find a good way to get that 1-gigabyte video down to size. For the best results, aim to compress your video so that it just fits the 100MB file size requirement. Many video-editing applications have the tools built in to compress your video to a variety of formats for the Web. If you don’t already have the tools and you want to use the H.264 codec, you could use QuickTime Pro (available for a fee at www.apple.com/quicktime) to compress video using the H.264 setting. It’s not mandatory to use H.264; you could also try one of the other recommended settings found at www.youtube.com/help. At one time, people thought it would be an advantage to compress video into the Flash video format that YouTube uses natively, but YouTube simply compresses every video that’s uploaded, whether it’s a Flash video or not. Luckily for us, YouTube now letterboxes any widescreen video, which subtracts a step from the task of compression.

Basic Techniques for the Home

To refine the process of compression, we’ll take a page from the still photographer’s darkroom. In the traditional darkroom, the photographer slices his photo paper into thin strips. He uses these slices to determine how the larger print will turn out. If there is an error, he’s wasted only a small amount of paper. This technique translates when compressing video for the Web. Since compressing video takes practice, you can select a few minutes of the longer video to compress, as a test. This way, if you compress using a setting of 800kbps (kilobits per second), and its visual quality proves unsatisfactory, you can make another attempt at 1200kbps shortly after. This technique drastically reduces the time to make a great compressed video, since you don’t have to wait for the entire 43-minute documentary on your Father’s WWII service to finish “cooking.”

Basic Ideas for the Small Biz

If you’ve found your stride as a videographer, and you’re looking to attract paying clients, compressing for e-mail and video-sharing sites doesn’t offer the flexibility you need. Think about starting a personal Web page, where you can include large videos that play back smoothly. Variable bitrate recording (VBR) trumps constant bitrate recording (CBR) in most compression situations. You can find these in the Adobe Media Converter (part of Adobe Premiere 3.0), as well as QuickTime Pro. VBR allows the bitrate to change and adjust for more bits per second for more challenging parts of the visual image. In this mode, you set the maximum bitrate, and the software will reduce the bitrate when it sees it’s not needed, allowing the file size to reduce even more. Two-pass VBR may take up to twice as long to compress, since it typically scans your video once before going over it a second time to complete the compression. Be ready to fix a snack.

Determine what video player your clients use and make something that caters to them, so they aren’t stuck fussing with an unfamiliar video player. For example, if they’re used to their Windows Media Player, make them a Windows Media file. The same goes for QuickTime and Flash video.


That’s a Wrap!

Distributing video online can be as fun as sharing a video with our high school classmates and as effective as delivering a stunning video to a client. As video compression technologies continue to update, don’t compress your time spent online at www.videomaker.com, where more info on distribution and compression can be found.

Andrew Burke works on documentary projects worldwide.

Sidebar: The World is Watching

YouTube has reported that people are compressing and uploading over 60,000 videos per day to its site. If that seems like a staggering number, consider that there are many more who are viewing videos than uploading. There are definite caveats to this type of mass-distro.’

There is a trade-off, though. If you simply want to show your video to family and friends, sharing it with millions of viewers isn’t as private as using e-mail, and the visual quality isn’t great.

Web video has received a bad rap lately, no thanks to the online video sharing sites. You know, those small video windows with chunky, blocky characters moving around? Compression doesn’t have to be a negative act. There are many positive aspects to compressing your wonderful video. If you’re sharing video with family, or you own a small biz and need to show off your stuff, the tips in this article will help you find out how to do it best.

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