On Tue, 2006-10-10 at 00:13 +0200, Hans Verkuil wrote: > There have been a few complaints about the Samsung image quality, even > with the 'Low Noise Amplifier' fix applied (as it the case with > 2.6.18/ivtv-0.8).
> First of all, make sure you have a decent signal. As I said, I now am going from cable into top-line, 8 port drop amp with +3dB gain. Quality is excellent now on direct TV tuner as well as the pair of PVR250s. > > But the other problem is that I suspect that while channels with a low > signal strength are now shown properly (or at least as good as the > Windows driver can produce), channels with a high signal strength may > now be worse than before. > That is exactly what seems to be happening with mine. With the LNA turned on and the +3dB amp, it looks like there is a lot of cross interference. With the LNA off, it is actually better, but a bit snowy. > The datasheet for the PAL variant of the Samsung tuner actually has a > flow chart showing when to set or clear the LNA bit, but the NTSC > datasheet has no mention of this. When I worked on this tuner I asked > someone who had the PAL tuner to take a look at a certain tuner > register to see how it fit with the flow chart, but it made little > sense to me at the time, so I ignored this flow chart completely. > Are the datasheets available anyplace? I would be interested in seeing them. > But based on the feedback of the last couple of days I may need to look > at this again. But I need help with this! > > First I need confirmation that the setting of the LNA bit does in fact > make some channels worse. So if you are using 2.6.18 and have these > problems, then please go to drivers/media/video/tuner-types.c in the > kernel sources, search for 'Low Noise' and you'll see the PAL and NTSC > Samsung tuner entries. Remove the '+4' from your tuner, recompile, > install and check if the problematic channels are now improved. Please > let me know whether or not that is the case! > > Assuming that removing the LNA does in fact solve this problem, then I > need help from someone who can compile kernels and do some tests and > preferably can do some testing/programming without too much help from > me. > The one issue I have is that I'm running with 2.6.17 and the tuner.ko changes (specifically adding or removing the "4" bit in the three lines. If I can make changes to the 2.6.17 versions I will do them. The problem is this is my production TV box, so can't easily play with a different kernel and things. I also will be getting a different board from Amazon.com by the end of the week or so. We'll see if it has the same tuners, and if it has the same problems. _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
