[MPlayer-dev-eng] Re: ccache

[Billy Biggs]

D Richard Felker III (dalias at aerifal.cx):

> On Mon, Jan 06, 2003 at 01:00:57AM +0100, Tobias Diedrich wrote:
> > 
> > IIRC there was an explanation in an older issue of c't magazine...
> > Ah, found it (Issue 13/2000, c'tplusrom 1/2000).
> > 
> > YUVabc
> > 
> > For a samples of Y b samples of UV in odd lines and c samples of UV in
> > even lines.
> 
> Hmm, then is the terminology even right? I thought the chroma
> components were considered as belonging to the even lines in most
> mpeg-type encodings. Or do we have are even/odd sense reversed because
> some engineers consider the top (0th) line odd because it's the
> "first"?

  I don't really think this is valid, since depending on your standard
for 4:2:0 the chroma samples are located in different places.  Sometimes
the chroma samples are from the middle of the four Y' samples, sometimes
it's between the two left samples.

  My reference for chroma notation is from Poynton, but his site is
down.  Here's his doc:

  http://vektor.theorem.ca/graphics/ycbcr/Chroma_subsampling_notation.pdf

  I got it from here, when it's back up:

  http://www.inforamp.net/~poynton/

-- 
Billy Biggs
vektor at dumbterm.net