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Audience: All
Last Updated: 2/21/2005 9:21:58 PM
Original Creation Date: 2/21/2005 9:21:58 PM
**All times are EST**
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Video Codecs and File Compression
By Erik Rodriguez
This article provides basic information on popular codecs and video compression used in video files.
If you have every downloaded a movie or large video file from the Internet, chances are it was "encoded" using some form of file compression.
Why is Compression needed?
File compression is needed for the obvious reason of saving space. An easy example to think of is "ripping" a DVD. Let's say Tom owns a DVD movie, and he would like to put it on a CD-R so he can watch it in a computer without a DVD-ROM. This is possible, but the file sizes must be manipulated for this to work. The table below shows the various capacity of today's disc media.
| Disc |
Capacity |
| OEM DVD Disc |
8.5 GB |
| DVD-R (double layer) |
8.5 GB |
| DVD-R (single layer) |
4.7 GB |
| CD-R |
700 MB |
As you can see, to get a file from 8.5 GB, to 700 MB it must be compressed. This is where the codecs come in. Popular codecs like Divx, Xvid, and 3vix allow these video files to be compressed. This is done by the combination of "like color" pixels. The result is a slightly lower-quality version. However, on a low resolution screen, or screen viewed from a short distance, the quality is nearly indistinguishable. Believe me when I say you will be surprised when you see a properly compressed film that is 700 MB in size. To the un-trained eye, it may appear DVD quality.
Installing Codecs
If you are not into whole the codec-collecting thing, your probably just want to install XP Codec Pack 1.0.4. It contains several popular codecs including Divx and Xvid. You should be able to view most films or videos distributed on the Internet. Remember that in order to download these movies from the Internet you must already "own" a real copy. We do not promote piracy here ;)
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