On Mon, 15 Sep 2003, Michel Bardiaux wrote: > In a long run of my capture application, I see, at random moments but on > average roughly once per houre, either 2 or zero frames in one 40msec > interval (PAL, 25fps). > This could be due to fluctuations in my system clock (it is NTP'ed but > nothing is perfect), or in the TV board, or just bad signal from the > cable company, but I wonder: what is the stability and long-term > accuracy of the 50Hz synch clock in a broadcast TV signal? Anyone know > where I can find such information? according to ITU Document 11/30E (1998), fluctuations of line frequency can be +/-0.02% and corresponding frame freq. +/-0.0001%. but I think, that card is syncing with the source, otherwise, You will get garbage instead of images. :) really, there is a great problem in all those grabbing hw: no cards with synched audio. don't ask me why. so, the difference in ADCs frequences makes bad game in video. but, it seems, that problem touches nobody.
