Monday, June 25, 2007

Digital Video

Digital Video

You’ve suddenly found yourself in a café in the Art District and have no clue how you got there—it happens to the best of us. You are bored for company and are wondering how to break into the group of digital video (DV) geeks in the corner.

“CMOS or CCD?” one of them asks after you exchange names. CCDs are Charge Coupled Devices, used for image sensing. The best digital cameras use 3-CCD arrangements to get top-quality video, and cost you half a kingdom. And CMOS (Complimentary Metal Oxide Semiconductor) is a cheaper but slightly lower-quality approach to image sensing, but it’s getting better.

Just say, “Oh CCD, no doubt. No compromises on quality”, this will have them swooning at your discerning eye and bottomless wallet (Ahem!).

Regular video is interlaced —the image is divided into two sets of lines that are displayed alternately to fool the human eye into believing it’s seeing a high-quality image. Progressive Scanned video displays all these lines in sequence, storing five times as much information in the frame. The result is High Definition Video (HDV), where faster movements appear much crisper than in interlaced video.

Video usually runs at 24 frames per second (fps). Saying “I’m shooting my next with a 24P camera” means that your video will run at 24 fps and is progressively scanned, and roughly translates to “I’m a George Lucas in the making!’”

DV25 is the standard compression format for DV; an hour of DV25 video takes up about 13 GB of space and is the best possible quality outside of raw, uncompressed video. MPEG-2 is another compression format that started out as a format for distribution, but is now used in recording as well.

“Real Men don’t compress,” you scoff, leaving them burbling something about more video on the same tape while you beckon a cab to take you home.

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