Moving Pictures: Codecs

The first time I ran into a video on the internet was at a Star Trek site. I scanned the photos and pictures, read the fan fiction and looked at the drawings of Kirk and Picard. I was moving pretty rapidly through the site and was just about to surf somewhere else when I noticed a hyperlink with a small movie camera next to it.

This looked intriguing. I clicked on the link, not knowing what to expect, and I got an error code. Something about an invalid codec? What the heck was this, I wondered? A codec? I thought I was going to get to look at a movie clip.

I looked on the web and found out that a codec was some software that, simply put, was needed to view the movie. Now the hard part came - which codec to install? I soon learned from my research that there are literally dozens, if not hundreds, of different codecs.

Let's back up a minute and it should all become clear. What is a movie, anyway? Well, a movie is simply a series of still pictures. Each picture is a frame of the movie. The frame is changed several times per second (anywhere from a dozen to fifty times or so), and this gives the illusion of movement.

The problem is that pictures and images are big, and the internet is based upon, at it's root, dialup connections. These connections are slow and it will generally take quite a while for even one of them to download to your computer. Add to that a couple of dozen per second, and you've got something that takes more than a second (or a hundred seconds) to display.

This is the basic problem that the codec attempts to solve. How to compress and decompress (hence the word codec) moving pictures so they do not take half the afternoon to download.

To give you an idea of how big a movie without using a codec really is - a one second clip of 24 frames can require over a dozen megabytes on disk (or more, depending upon the size and quality of each frame). For those people still on a dialup line, it is generally impossible or impractical at least to view one of these movies.

So what happens is the codec is a method whereby the movie is compressed into a smaller size, stored, transmitted, and then decompressed as it is being viewed on your PC.

There are many different codecs because people from all over the world have created new and different ways to do this compression. Some codecs are very good at maintaining quality, but they require extreme amounts of CPU to decompress. Others are grainy but fast. Some might be good for color and others for black and white. Thus, there are different codecs for different applications.

So what does this mean to you? Well, many people use a product such as Windows Media Player to view their videos. This application will automatically see if the proper codec has been installed for the video that you want to watch. If so, the movie can be displayed. Otherwise, the Media Player will check it's library to see if it can download the proper codec. If it finds it, the codec will be installed and the movie will play. Otherwise, you will have to search for and install the codec yourself.

Where do you find codecs?

Codec Corner
Codec Central - List of Codecs

How do you install them manually? The old way was to use the Multimedia control panel (also known as the Sounds And Multimedia control panel). Just download the codec as instructed and add the codec using the control panel (there are instructions on Codec Central and other sites which explain precisely how to do this - installation varies by codec and most codecs will have installation programs that handles this automatically).

Once you install the codec you can play the movie - assuming you have the movie player - yes, you need a player in addition to the codec. Windows Media Player will play many kinds of movies. QuickTime Player and Real Player are examples of other brands of player.

I hope that clears up a little of the mystery about video codecs.

Discuss Codecs in the Movie Makers Forums

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