Date: Mon, 22 Mar 1999 17:18:34 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: multimedia@freebsd.org Subject: bad video effects with vic&3.1 Message-ID: <199903221618.RAA06121@labinfo.iet.unipi.it>
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Hi, after switching to 3.1 i notice some nasty effect in video capture with vic and the bt848 driver. What happens is that at times the image shows a lot of horizontal lines in each DCT block, plus something looking like the "snow" effect on TVs when you have poor signal. Same hardware did not have this problem on 2.2.x, and i can reproduce this reliably on all systems i have. I am not sure if the meteor driver has the same problem -- i could not reproduce it but i only ran it for a few minutes (the problem with the brooktree appears reasonably often). Possible sources of problem: + maybe some change in vic, using one frame at a time on 2.2.x/ continuous capture in 3.1 ? (this would explain the problem as data would change in the middle of the DCT transform). + some change in the PCI code that somehow causes DMA to abort or write some bad data in memory. same as above. + changes in the driver (but this seems not to be the case). Any ideas ? These effects are very annoying, plus every scrambled frame takes a lot of bandwidth! cheers luigi -----------------------------------+------------------------------------- Luigi RIZZO . EMAIL: luigi@iet.unipi.it . Dip. di Ing. dell'Informazione HTTP://www.iet.unipi.it/~luigi/ . Universita` di Pisa TEL/FAX: +39-050-568.533/522 . via Diotisalvi 2, 56126 PISA (Italy) -----------------------------------+------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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