What Does Overlay Mode Do?

[Snee]

Originally posted by Vamp@12 July 2004 - 15:25
But what does running two images on each other achieve?

One guess is that it's like this:

When you have several windows open on your desktop the information for each still goes out to the monitor or somesuch, only you can only see the topmost one, 'cos that information is noted as visible or such. Possibly this makes for smoother transits or something since it's already loaded in you ram or so.

Whereas when turning it off, the only info that goes out is the visible one.

[lynx]

Overlay mode: The graphics card sets aside an offscreen buffer in its own memory, the image source card (tv card) transfers the picture in there by doing PCI bus master cycles. The graphics card scales, sizes and gamma corrects that, and fits it into the main picture.

Source

In other words it gives the graphics card the opportunity to modify the image according to your preferences, rather than simply take the image as presented. But obviously this takes processing time so you may not get the full frame rate.

[Snee]

Originally posted by lynx@12 July 2004 - 19:34

Overlay mode: The graphics card sets aside an offscreen buffer in its own memory, the image source card (tv card) transfers the picture in there by doing PCI bus master cycles. The graphics card scales, sizes and gamma corrects that, and fits it into the main picture.

Source

In other words it gives the graphics card the opportunity to modify the image according to your preferences, rather than simply take the image as presented. But obviously this takes processing time so you may not get the full frame rate.

yep by buffering the information, saving all the screen info or something.

Keeping everything available so it can be manipulated on the fly.

Not just the visible, or so I understood it.