On Wed, 4 Sep 2002, Michael Hunold wrote: > I was always wondering how the synchronization is done when you directly > connect to a tv via scart. What I mean is: is the video output via > mplayer or xine syncronized to the vertical refresh in any way? > > If not, how bad are the tearing artifacts? If there is no > syncronization, you will see glitches on vertical lines when the camera > is moving... > > Does the native xv video driver use the vertical refresh interval to > switch pictures? Hi Michael, The question of synchronizing mplayer/xine frames to the raster refresh isn't peculiar to VGA->SCART. Its a general issue for any raster-scanned output (VGA monitor, LCD, LCD projector, TV via TV-out or anything). X's XVideo interface (what mplayer's -vo xv driver uses) doesn't synchronise to the raster refresh. So, yes, tearing artefacts can be seen on pans. I use such a setup. I'd obviously like to get rid of the effect, but do find I don't notice it especially any more. There's been talk occasionally about trying to fix this in X - but I don't think anyone able to deal with X source who cares enough has come along... Other mplayer drivers do double-buffer frames and flip on refresh. This removes the tearing artefacts but leaves (or, worsens even) judder due to the fact that frames aren't visible for an exact even time period. This is a difficult and subtle business. Even harder when you have video whose frame rate isn't the same as the display refresh. Cue people like Billy Biggs and Dave Chapman who know and care about this much more than I. Regards, Steve Davies
