Es schrieb Trent Piepho: > > On Thu, 11 Dec 2003 v4l@xxxxxxx wrote: > > > Grab all frames (i.e. 25 QBUF and DQBUF per second) and copy only the > > > ones you want, maybe on the basis of the timestamp or timecode returned. > > > Even if your QBUF were *perfectly* rythmed, what counts is the video > > > synchro signal, not the system clock. > > > > > > > Hi, > > > > That's what I used before, and that works ok. The problem is that I'm using > > 4 or more grabbers in one PC now, and capturing everything and skipping > > frames causes too much data on the PCI bus, resulting in image distortion. > > (distorted horizontal lines at random places, etc)... > > You need to use the temporal decimation register on the bt8x8 chip, to have > the card drop frames. This is the only sure way you can get smooth dropping > of frames, without capturing all frames and deciding what to drop yourself, > which of course has the PCI bus problems you mentioned. > > The only thing is the temporal decimation register is a strange thing, and > doesn't appear to work as described in the data sheet. > > I remember a thread on this list a long time ago, were we discussed it. I > think someone actually managed to get it working correctly and had a patch > for the driver. I can't find any searchable archives for this list, but > maybe there is some information out there. > It is truncated in the searchable archiv http://www.riverside.org/archive/html/video4linux but last tracks point to redhat video4linux-list/2002-May/msg00062.html and it is downloadable here http://www.spinics.net/lists/vfl/msg01145.html regards, Hermann
