21 Oct
2006
21 Oct
'06
1:59 p.m.
On Fri, 2006-10-20 at 16:53 -0400, Paul Davis wrote:
On Fri, 2006-10-20 at 22:44 +0200, Tim Goetze wrote:
I think any Linux system with DRI can do this. Check /proc/interrupts -
if your video card is listed, then you should have vsync interrupt
capability.
Lee
[Fons Adriaensen]
it was missing from X until Xorg put it back in as an extension. its
obviously not of much use in a general purpose X app, since the display
may not be the host on which the app runs, making access to the vsync
pulse pretty pointless.
Input the vertical video sync signal via the audio
card and analyse
its timing in terms of audio samples (e.g. using a DLL). This will
enable you to predict where the next sync will be in the audio input.
Back in the 80s, the humble Commodore 64 could be readily programmed
to fire an interrupt on vertical sync. Have 20 years of progress
really deprived us of this fine feature, or is it just missing from X?