In the 1980s, shooting and editing movies got only slightly more complicated with the introduction of VHS, VHS-C and Betamax. You could read a two page article and know the differences between competing video formats. When video went digital though, everything went out the window. Suddenly there was a bewildering array of video formats - .wmv, .asf, .rm, .mov, .mpeg, for compressing files, - and on top of that, many of these standards had their own substandards (MPEG-1, MPEG-2, etc.) How's anyone supposed to keep it straight?

Containers and Codecs

Possibly one of the most confusing things about digital video formats is the idea that there's a "container" and "codec" - You might think it's enough to make you yearn for the days when you could just put a tape in the camera and start recording, but you'd be wrong. The plethora of video formats mean that whatever type of video production you're doing, there's a good way to make it happen. Twenty years ago everybody was watching movies the same way - either on a screen via a projector, or on a television set. Today many, many more options exist and people are taking advantage of them all - from high-end HD video with surround sound shown in a top of the line home theater, to video streaming from a cellphone - video is everywhere and having a grasp of the various formats will ensure that your video gets where it needs to in the best way.

An Analogy

Trying to figure out exactly what containers and codecs are can be a little bewildering because it's a very technical subject. You can think of containers as a type of publication: a hardback book, a glossy magazine, a newspaper, a pamphlet, a gum wrapper - all of which can contain words and other things like photographs, or cartoons, and yet each one works in a different way. Think of the codec as the way of displaying the information you want in your publication. You can, for example, print War and Peace on Bazooka Joe bubble gum wrappers, but it will take thousands and thousands of them and nobody will want to read it that way; in the same way you can put your vacation footage on an uncompressed DV format, but you won't be able to stream it over the web. Similarly, you likely want your copy of War and Peace to be beautifully bound in hardback, but that's not the proper container for a takeout menu someone's going to shove in your mail slot. Words with drawings could properly be placed in a comic book, or a hardback book, or a newspaper, but the images in an art catalog or high-end fashion magazine require heavy-weight glossy paper to reproduce properly. Every video application has a proper codec and container. To add one more layer of complexity: both codecs and containers go in and out of style - so a format which was popular a few years ago, may be something few people are using today.

Lossy vs Lossless Compression

Usually, when video data is compressed some of it is lost. Video compression software works by looking for redundancies in a frame (such as one bit of blue sky next to another bit of blue sky) and representing the redundancies together. At very high rates of compression this becomes obvious, but at lower rates it's difficult for people to notice. There arises a desire in every movie maker to try to use lossless formats, which preserve all the original data, but the compression ratios aren't good enough (yet) to make them practical. Choices at the moment are to use the highest quality compression available for your intended purpose and to have multiple versions of your files for multiple uses (i.e. one file for web-streaming, another for disk-based distribution, another for standard definition DVD, another for Blu-ray, etc.).