10 bit per channel DVI output

[faculaganymede]

Graphics gurus,

ATI x1800 spec states "16 bit per channel floating point HDR and 10 bit per channel DVI output." I need some help to understand what this is saying.

Does "16 bit per channel floating point" mean 16 bit dynamic range for each of the RGB channels in the frame buffer?

Does "10 bit per channel DVI output" mean 10 bit dynamic range for each of the RGB channels in the DVI output? If yes, is 10 bit per RGB channel currently the best there is for PC graphics cards?

I couldn't seem to find this kind of info in the Nvidia card specs.

[Victorshen]

dvi 1.0 spec only allows 8bit

[faculaganymede]

Victorshen, could you explain?

I got "10 bit per channel DVI output" directly from the ATI x1800 spec: http://www.ati.com/products/RadeonX1800/specs.html

Does anyone know where I can find some documents that explains the data bit flow from framebuffer to DVI output (for any high-end graphics cards)?

Thanks.

[Victorshen]

http://www.ddwg.org/lib/dvi_10.pdf

have a look :)

[hordaktheman]

From what I can tell, this "10 bit per channel" only seems to apply to the RGB channels, with the alpha channel being limited to 2 bits. That amounts to 32 bits total, which would fall within spec. And seeing as an 8 bit alpha channel is largely redundant, it should allow greater color fidelity. I'm not entirely sure about this, though.

Of course, native support requires a 10-bit capable display, but 8 and 6-bit displays get an internally dithered, downsampled version of the image. Gamma and color correction, for example, are both done in 10-bit and dithered down to 8 and 6-bit for those displays, just like previous 8-bit cards did on 6-bit displays.

I imagine the dithering artifacts to be much lesser, though.