[FFmpeg-devel] [RFC] 16-bit component library
Sun May 27 00:10:47 CEST 2007
On 5/26/07, erik98 at sunflower.com <erik98 at sunflower.com> wrote:
> >?yvind Kol?s wrote:
> >One thing you do not seem to take into account is the positioning of
> >chroma samples for planar pixelformats using chroma sub-sampling,
> There seem to be two options here.
> 1) Explicitly enumerate the extra "components" (ie. Y,U,Y',V = 4 components)
> 2) Add a component sub-index. (ie. Y,U,Y,V)
The issue I tried to raise is not that a you end up with multiple Y
components, but the offset of the chroma samples in relation to the
luma samples. Some googling brought me to a page with some diagram
showing some different ways the chroma samples can be positioned.
Different positions for chroma samples in relation to luma samples
means that the interpolation of chroma samples is needed when
converting to a pixel representation without chroma subsampling.
?The future is already here. It's just not very evenly distributed?
-- William Gibson
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