Should I?....

[bde]

I was wondering if anyone would like a guide on how the very many video codecs work, including the improtance of matrix's, and special coding techniques. I'll begin writing the guide today... during school... so, I should have a 'beta' version out by the end of the week. If anyone wants to add to the project, just post here. Thanks.

[bde]

First Article... I'll eventually collect all these and post a full guide... if anyone gives a damn at all...


Article #1: Motion Compensation

Motion Comp, one of the most important features of most modern day codecs. Starting with MPEG1, this feature helps to determine the way a frame of video should be encoded or decoded, by setting up a quality for the amount of motion in a scene. MPEG1 was very new to this idea, and has low to mid quality motion compensation. Basically, the codec forces a quality on the motion of the film. That's right, even if the video was shot with the best camera's on the face of the earth, if the video was encoded with a low motion compensation, then the film will have possible choppy scenes, and camera movements will be very subtle. This can also be used as an effect in post-production movies, but why you would want crappy quality motion scenes, I do not know. For cartoons, however, you can set this to about 75-80%, which can be found in most MPEG1 &2 codecs, and most MPEG4 codecs (such as Divx, Quicktime, etc...). Motion compensation in some older movies, where action and high camera motion isn't a concern, this can be set to 40-80%, as the film will probably not require such excessive motion quality as say, "The fast and the furious". This is just an example. Quick motion combined with a low motion compensation will give you horrible artifacts in the video, as well as missing data (IE: color changes, scene clipping...). Low motion combined with a high setting is just overkill, and you do lose valuable space and encoding time when set too high. This is one problem with the current generation of codecs. If only there was a way to set up an averageing motion compensation, so that you would not need to know exactly how much motion there is in a movie. This will probably never be added, as it would take up too much time to analyze each and every frame, and then compare to a correct image using image quality analysis. (Say that 5 times fast...).

If you have any questions or comments, post them here, in this thread... Whatever.