On Fri, 2006-10-20 at 16:53 -0400, Paul Davis wrote: > On Fri, 2006-10-20 at 22:44 +0200, Tim Goetze wrote: > > [Fons Adriaensen] > > >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? > > 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. >
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
