Andrew Coppin <orp### [at] btinternetcom> wrote:
> What's an MPEG-4 codec when it's at home? I thought a codec is a codec...

  That's like saying that an image format is an image format... You certainly
can tell the difference between, for example, an image in BMP format and
in JPEG format?
  And you probably can tell the difference between a WAV file and an MP3
file?

  An MPEG-4 codec is a codec which implements (all or part of) the MPEG-4
standard.
  The version 4 of the MPEG standard is more developed and then the
version 2 (which eg. DVDs use), which is more developed than the
version 1 (which is what most .mpg files are).

  Typically MPEG-4 compresses video to something like 1/4 or 1/8 of the
size of the equivalent MPEG-1 video (with the same visual quality).
Another advantage of MPEG-4 is that the compression quality is not
highly dependant of the image resolution (unlike in MPEG-1 where
doubling the resolution invariably doubles the size of the file).
  (In fact, increasing the resolution increases the quality of the video
at the same bitrate. I know this from experience.)

> I was under the (mistaken?) impression that there are legal restrictions on
> the use of DivX...

  What legal restrictions?

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -

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