[Open-graphics] RGB/YUV converstion... importance?

[Attila Kinali]

On Wed, 13 Sep 2006 13:41:40 -0400
"Timothy Miller" <theosib at gmail.com> wrote:

> > 4:2:0, the most important subsampling format is missing
> 
> Can you describe it?

4:2:0 is the one, that has a subsampling of
factor two in both horizontal and vertical direction.

A c&p from a mail from Michael Niedermayer
(http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2006-September/044692.html)
---
progressive 4:2:0 (mpeg1)
Y Y Y Y
 C   C
Y Y Y Y

Y Y Y Y
 C   C
Y Y Y Y


progressive 4:2:0 (mpeg2/mpeg4)
Y Y Y Y
C   C
Y Y Y Y

Y Y Y Y
C   C
Y Y Y Y
---

Note that the chroma samples are located half a pixel down
vertically in both versions, and half a pixel to the
right in the mpeg1 case.

IIRC the mpeg2/mpeg4 variant is the most used case.

The mail lists also an interlaced variant, but we
do not have to care about that unless we make a
hardware deinterlacer which we should not IMHO.


I have to reread the rest of your mail somewhen else,
when i'm a little bit more awake (probably this weekend).

			Attila Kinali

-- 
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