Peter Surda ([EMAIL PROTECTED]): > On Fri, Oct 19, 2001 at 12:21:12AM -0400, Billy Biggs wrote: > > The +/-5ms error here is visible, especially on big cinematic pans. > I REALLY doubt what you perceive as an error is a 5ms difference.
No? I'll post up a good example later today. Consider a pan where the time between frames goes like this: 40ms, 45ms, 35ms, 45ms, 42ms... So, the second frame is shown for much longer than the first or third. On a smooth pan you'll see the background shudder as it goes by. Think of a skateboard video. It's really horrid. > Though I agree that current vsync adjusting in XF86drivers (those that > support it e.g. ATI) is insufficient. I see noticeable disturbaces on > TVout (thought not on monitor), I believe it is because from time to > time the thread that calls XvShmPutImage has "missed" one frame and > suddenly the difference between 2 frames becomes double. Speaking of TV output, if you're outputting interlaced material to a TV then you MUST have accurate vsync, field dominance, and some way of ensuring you never miss a field. Otherwise you get crazy effects of people jumping back in time when you miss a field blit. Currently it seems like all TV output APIs assume you're sending progressive video at some very low framerate. Argh. :( One reason you may be seeing disturbances is that your TV encoder is only blitting frames and will wait until the next frame refresh before showing the next. This gives your output display a refresh of 25hz, and if you're not synced to it, you'll see much worse effects. Consider trying to play a 24fps video: you'll cycle around the real output sync pretty badly. Ideally for playing 24fps on a 25fps output, apps should speed it up by 4% (same as film->PAL video). To do so though we need to know information about the output capabilities though. -- Billy Biggs [EMAIL PROTECTED] _______________________________________________ Xpert mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/xpert
