Well, I made some of the suggested tests, and here are the results. I disconnected from the powerline every device except the monitor and then recorded from the satellite receiver (yes, the one with 35 meter long cable...): same results.
I tried with decimation 2: same results. I tried with JPEG quality 80%: same results. I tried with the new card, but with "streamer" instead of lavrec: same results. Right now I got a suspicion: I have a wireless keyboard (and mouse). Could it interfere in some way with the capture cards? And why this interference doesn't affect some colors? Before go crazy, I will try with a standard keyboard and mouse, I should have one somewhere. Best regards. Mark Heath wrote: > I've split this image into it's Y-U-V channels, > > There appears to be no noise in the chroma channels only the Luma > channel. > > This could be due to: > > * the chroma channels being half resolution, not enough resolution to > represent the noise pattern. (below the nyquist value) > * the interference frequency is not high enough to cause colour shifts. > > Or due to JPEG compression. > > * notice that the noise falls cleanly within Macroblock boundaries. > * the noise may be falling below the quantizable threshold in those > areas. Thus not being encoded into the Macroblock. > > If you get to capture the image again, maybe do it at a very high > bitrate, so we don't see compression artifacts. > > I have seen this type of noise before, even recorded onto a digibeta > provided by Universal, but never looked into methods of removing it. > > Have you tried a bit of trial and error, to see if the noise goes away? > > * Turn off all electrical appliances. > > * Try the capture source closer to the computer. > > Mark > > -- > Check out my latest YUV tools at http://silicontrip.net/~mark/lavtools/ > > On 08/03/2008, at 8:34 AM, Andrea Giuliano wrote: > >> Okay, you and Burkhard suspect radio interference. But you have not >> seen >> the full pictures I sent to Bernhard Praschinger. In those picture you >> could see that the pattern is not spread all over the frame: the >> trunks >> of the trees, and the rocks too, are only affected very little, if >> even >> not at all. Could an interference affect some colors and not other? >> I'm >> not expert of interference, nor of colors, indeed? >> >> So here is a link to one of those frames: >> >> http://www.webalice.it/sarkiaponius/00000669.jpg >> >> It's just 54K big. If you zoom around the trunks or the rocks you will >> surely understand what I'm trying to say (sorry, my native language is >> neapolitan, not english...) > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Mjpeg-users mailing list > Mjpeg-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/mjpeg-users -- Andrea ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Mjpeg-users mailing list Mjpeg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mjpeg-users
