View Full Version : PseudoColor overlay bits

08-22-06, 03:48 PM
Hi all,

In overlay mode (8 bits pseudocolor + 24 bits truecolor), how come the number of colors in pseudocolor plane is 32 (5 bits).

Is it possible that the overlay is downgrading pseudocolor from 8 bits to 5?

Did I missed some configs in xorg.conf?


08-28-06, 05:27 PM
Hi begal,

I assume you're talking about visuals that look like this (from xdpyinfo):
visual id: 0x70
class: PseudoColor
depth: 8 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0x0, 0x0, 0x0
significant bits in color specification: 5 bits
This means that the visual has 8 planes, for a total of 256 colormap entries. Each colormap entry has a depth of 15 bits (5 bits per channel) for a total of 32,768 colors per colormap entry. The reason it's 5 bits per channel and not 8 is because the overlay hardware only supports depth 15.

08-29-06, 10:19 AM
My xdpyinfo is the same,

That means that we are stucked with 32 colors in pseudocolor when using overlay mode?

08-29-06, 10:25 AM
Is there any cards doing 24 bits overlay ? (8 bits per channel)

03-22-07, 09:13 AM
I'm also looking for a card that can support the full 8 bits in overlay mode. I've got a QUADRO FX 560 but it gives me only 5 significant bits per color. Which NVIDIA cards support the 8 bits/color in overlay mode?