On 01/28/2006 08:29 PM, Rudy Zijlstra wrote: > Michael T. Dean wrote: >> On 01/28/2006 12:46 PM, Dylan R. Semler wrote: >>> Michael T. Dean wrote: >>>> On 01/27/2006 01:07 AM, Robert Johnston wrote: >>>>> On 1/26/06, Dylan R. Semler <[EMAIL PROTECTED]> wrote: >>>>>> For analog, the picture quality is pretty bad (noisy)... The >>>>>> picture quality is much better using tvtime and those lines do not >>>>>> appear. >>>>>> >>>>> As for the noise, make sure that Myth is tuning into the same >>>>> frequency (EXACTLY the same frequency) as TVTime is. It sounds like >>>>> Myth's off by a few Khz. >>>>> >>>> Being off by a few KHz shouldn't matter. Many of the NTSC cable >>>> channel frequencies are off by 12.5 KHz (and the same goes for IRC, >>>> and HRC varies by 5-15KHz), but the tuner hardware's fine-tuning >>>> mechanism should still be able to find the appropriate center >>>> frequency. See >>>> http://www.gossamer-threads.com/lists/mythtv/dev/164614#164614 >>>> (which was totally ignored by the guy complaining in Trac that the >>>> frequencies are off) for an in-depth listing of what frequencies are >>>> off and why it shouldn't matter. >>>> >>>> If you (Dylan) want to try an academically-correct list of frequency >>>> definitions, I'd be happy to create one for you (against SVN--just >>>> let me know which frequency list you're using: ntsc_bcast, >>>> ntsc_cable, ntsc_hrc, ntsc_irc (I'm assuming NTSC based on your >>>> e-mail address)), but you'll have to do all the testing because I >>>> don't have any RF-modulated sources. >>>> >>> Well it's worth a shot. I'd love to get better picture quality. I'm >>> using ntsc_cable. >>> >> OK. Attached is a patch... >> >> If there really is a >> difference (and I still don't think there will be)
Read this ^^^^ > probably good to improve, but.... > > for the silicon tuners i know about, (which are both the ones we use on > our products as well as some others), this makes no difference at all. > Most modern (silicon) tuners are able to finetune to the correct > frequency if the initial frequency is within 125KHz of the correct > frequency. > We make use of this is the scanning algo, as this makes it possible in > Europe to scan with 250KHz steps in case we have to do a frequency sweep.... > Please keep in mind, Europe cable does not have any standard to adhere to. > That's what I've been saying all along--since someone mentioned that the frequency might be off by a few kHz... However, it's hard to convince people it's not a problem if they can't test it for themselves... ;) Personally, I don't think it's worth changing the definitions in the source, but between the "This is so trivial to fix that it's silly not to." comment in Trac ( http://svn.mythtv.org/trac/ticket/610 and my response http://www.gossamer-threads.com/lists/mythtv/dev/164614#164614 ), and "common wisdom" about using the finetune values to adjust frequencies by a few kHz (which is often suggested), I figured a patch on the list that lets people see for themselves that it doesn't matter would be the best way to get other people to see it my way. Mike _______________________________________________ mythtv-users mailing list [email protected] http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
