[linux-audio-dev] best option for audiovisual synchrony

[Paul Davis]

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.