Digital Video Basics

What You Need To Know

Observation #1: However big your hard drive is, you're going to need a bigger one.

Depending what how long a video is and what format it's in, video files can be huge. For importing video from a digital camcorder, unless your software does on-the-fly compression, expect the files to take up slightly over 13 GB (GigaBytes) per hour of video.

Obviously, video files that size are not particularly manageable, and certainly cannot be sent over the internet. That's why you'll usually be working with compressed video of some sort. The bit of software that works in the background to compress and uncompress video into various formats is called a CODEC (short for COmpressor/DECompressor).

Types of Compression

Movies in North America that are distributed on DVD, as well as most satellite TV and digital cable services, use a form of compression called MPEG2. From mpeg.org: "MPEG (pronounced M-peg), which stands for Moving Picture Experts Group, is the name of family of standards used for coding audio-visual information (e.g., movies, video, music) in a digital compressed format."

Basically what it does, is run the video through a mathematical algorithm which compresses it, trading off picture detail for smaller file sizes.

Although MPEG2 is the "standard" behind most commercial video formats, and it does a pretty good job at making the video take up less space without losing too much quality, MPEG2 files are still pretty big, at around 2GB per hour of video for something that looks half-decent. Still much too big for sending over the internet.

Because of that, a few more formats have sprung up and become very popular for computer use, namely DivX and xVid. Both of these formats use much higher compression without losing very much quality. Typically, a full 2 hour movie can be stored using either DivX of xVid format in less than 1 GB of space.

So what's the catch?

You can't "legally" download commercial hollywood movies in these formats. While the're wonderful for saving space, they're lacking a feature that we as consumers typically don't actually want. It's something called DRM, or Digital Rights Management, and it's a way for the producers of content (such as movie studios) to control how and where you can play your digital media. DivX and XviD files can be copied to any PC or other device that supports that format, or shared over the internet, without worrying about who actually owns the content (legal issues aside). The content producers want everyone to buy their own copies, and want to limit your ability to make copies for other people.

Where does that leave me?

Good question. You can choose to legally purchase movies over the internet, most likely in a proprietary format, along with whatever viewing limitations that might entail, or you can illegally download movies or TV shows using any of numerous file-sharing applications and web sites. Or you can rent or borrow a DVD and "rip" (which really means copy) it to your computer, which is also technically illegal, or buy a DVD, rip it, and keep the DVD in your closet as a backup.

What about home movies from my camcorder?

That's a different story. You can do whatever you want, since you own the rights to it. The only thing you really have to worry about is how much space it's going to take up on your hard drive. Typically, you connect your camcorder to your computer with what's known as a Firewire, or IEEE-1394 cable. Only digital camcorders have the necessary connection, not older "analog" Video-8 or Hi-8 camcorders. Your computer also needs a matching port to plug the cable into. Most newer computers will have the necessary port. Then, using a video editing program, you transfer the video from the camcorder to your computer. The exact process depends on your editing program and camcorder. You can usually use the editing program to convert your video to MPEG2, QuickTime or Windows Media format, and sometimes even to DivX.

Anything we're missing? Let us know.

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