Re: [Discussion] Subpixel rendering issues with compressed video output formats

[Behdad Esfahbod]

What Vitor is referring to is when the graphics cards sample down the resolution of certain channels, typically in the YUV color space, but sometimes maybe in RGB, eg. encoding every 4x4 block of blue channel only, 2x2 of red, and 1x1 of green.

It's as if you JPEG compress the subpixel-rendered image and decode it...

behdad
http://behdad.org/

On Mon, Jun 9, 2025 at 12:11 PM Alexei Podtelezhnikov <apodtele@gmail.com> wrote:

If you are referring to color fringing when the text is moving and RGB are firing up with some delay. I have no idea how to synchronize it. This is likely out of scope of FreeType.

> On Jun 9, 2025, at 14:01, Alexei Podtelezhnikov <apodtele@gmail.com> wrote:
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> Vitor,
>
> Frankly, I can hardly relate your problem description to font rendering. Can you possibly rephrase it? In FreeType speak LCD rendering is just triplicated for 3 arbitrary color channels with slight differences depending how these channels are spatially shifted. Regular antialiasing is just a special case assuming that three channels are not shifted at all. Note that FreeType does not assign color to the channels.
>
> Alexei
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