[mythtv-users] Quick and dirty workaround

[Jay R. Ashworth]

On Wed, Aug 11, 2004 at 05:57:58PM -0700, Bruce Markey wrote:
> Jay R. Ashworth wrote:
> > On Tue, Aug 10, 2004 at 09:35:20PM -0700, Bruce Markey wrote:
> >>...yet there it is. The rules that govern what station broadcast
> >>from where are moot. The point is that devices that output RF
> >>normally have a a mechanism to select the output frequency and
> >>the choices are suspect at best. This is why super VHS included
> >>a new type of connector to get away from issues of broadcast
> >>interference entirely.
> > 
> > 
> > No, it *so* isn't.
> 
> 1) Devices that output RF do have a mechanism to select the output
> frequency.
> 
> 2) S-video does avoid issues of broadcast interference entirely as
> you acknowledge in next two paragraphs.
> 
> Which are you saying 'no' to?
 
"this is why S-video included a new type of connector to get away from
issues of broadcast interference". 

That implies, at least to me, that the issue of S-video's existence at
all, and in addition it's choice of a specific connector, has *anything
at all* to do with braodcast interference.

It doesn't.

RF signals, as might be found at the normal television viewing location
not located within 10 miles of a transmitter tower (:-), aren't going
to have any more effect on a composite video signal running through a
single RCA cable than they will on an S-video signal running through
*it's* sort of connector: neither of those signals is likely to take
visible interference from any broadcast signal regarless of channel.

The issues are orthogonal.

> > S-video is completely unrelated to RF interconnections; *it's* job was
> > to deconflict NTSC 3.58MHz subcarrier color from the luminance of a
> > baseband video signal, as I noted in another posting, so that you
> > didn't have to use brickwall or comb filters to do that.
> 
> That is true also. The fact that you interpret this to be more
> important does not lessen the fact that the signal is not RF.
> Early VCRs came with only a coax out and an adapter for antenna
> leads. In designing a new format for a better signal from a VCR,
> an important criteria was to avoid RF interference. Separating
> luma and chroma made it better than composite.

But, of course, as I noted in another posting, the concept behind
S-video wasn't *invented* for consumer S-VHS and Hi-8 recorders, it's a
modification of the U-matic Dub Out connectors, which goes back, if
memory serves me correctly, to the VO-2860's in about 1982 or so, which
well predates 87 for S-VHS.

> > *Any* kind of baseband video interconnect is an attempt to avoid local
> > broadcast RF interference; S-video isn't anything special on that
> > specific front.
> 
> And I've never said anything to the contrary. If you go back
> to the discussion of the user questions and answers from before
> you went off-topic in a desperate attempt to prove that you are
> correct about irrelevant minutia,

Aw, get over it, Bruce, willya?

>                                   the point was that either
> s-video or composite were better choices than coax because of
> RF interference. He could have used s-video so the topic was
> never choosing s-video over composite because of luma and chroma
> separation.

Then why is it that you raised that issue?

> > I wasn't pissing at all; I was trying to be informative.  If you think
> > that one counter example to someone else's rule, which I was merely
> > quoting, changes my attempt to be helpful into "pissing", then my
> > apologies and condolences.
> 
> You've neglected to include your superior definition of a pissing
> contest.

I didn't define a pissing contest.

I merely applied the definition I carry internally, which involves
minor things like *motive*, to what you said, and decided it didn't
fit.

> The question was "In other words, shouldn't mythtv just default
> to [using the preset channel] when I'm using an external channel
> changing program?" The answer is that devices that output RF have
> a switch to select which frequency to use so myth needs an option
> to know which preset channel is to be used. Why manufactures
> believe that "3" and "4" are adequate choices for most situations
> is irrelevant. What is relevant is that devices DO have a selector
> switch or software option.

Yes, and I know that, and I knew that when the gent asked his original
question; the awkward phrasing of said question didn't make it clear
that that feature fixed his problem.

> I know for a stone cold fact that there are regulations regarding
> where transmission towers can be placed, what frequencies they can
> carry and the maximum wattage. I know that atmospheric conditions
> affect signal strength at a distance. I know that very few people
> watch TV at the base a transmission tower and that most people
> live at varying distances from several transmission towers whose
> signals they can receive. I know that large expanses of rural
> America can get at least a snowy signal on both channel 3 and 4.
> I know that the assumption that at least one of these channels
> won't have enough interference to be too big of a problem is not
> very reassuring.

Well, IME, if your cables are all crimped correctly, and you have a
good ground on your rack and decent quality equipment, it takes a
fairly damned strong broadcast signal to cause appreciable
interference.

>                   And, I know there are armies of people reading
> mailing lists looking some trivial point to try to show off how
> smart they are.

Shame that you can't make me out as one of them, no matter how you try,
isn't it?  :-)  I've been at this for 20 years, I can enjoy a good
technical flamefest as much as the next guy, and I realize that not all
the civilians on a list like this 'get' that... but you don't sound
like a civilian to *me*, so I'm having a hard time figuring out why you
sound like you're trying to make it personal, not just business.

> With all this in mind, I mentioned that devices have have a
> selector switch and the usually choices are 3 and 4 because "most
> cities" have one or the other but not both. I deliberately chose
> the more flexible "most" knowing that there would be numerous
> people chomping at the bit to chime in that they get both where
> they live. This does not change the fact that there IS a selector
> switch on devices with RF out.

Fine.  We had that.

> The reason that I was conscious of how I worded it is because I've
> read Usenet for decades and have seen this pattern thousands of
> times:
> 
> 1) Someone asks a question.
> 2) Someone else give a correct answer.
> 3) Someone else tries to show off how smart they are by nit-picking
> a point in the correct answer that adds nothing to answering the
> original question.

1) I wasn't trying to show off.
2) No, I wasn't entirely trying to answer the original question.
3) No, I don't think it contributed *nothing* to the discussion, or,
obviously, I wouldn't have bothered.

> What I hadn't anticipated is that some know-it-all wannabe would
> want to show off that he was 'the one' who knew that there was such
> a thing as the FCC to regulate transmissions and replace my cautious
> "most cities" with the absolute "all cities". This in no way
> changes the fact that there IS a selector switch on devices with RF
> out. Instead, it invites other to try to show off that they know
> more about whether or not anyone receives adjacent channels. Totally
> askew to the topic. Pointless pissing contest.

Projection is a horrible thing.

> Any housewife, construction worker or secretary that ever set up a
> VCR has seen the switch for 3 or 4, read the quick setup guide and
> knew to set it to 4 if they get a strong channel 3 or the other
> way around. Anyone who ever saw this could infer that there must
> not be any place where there is both a strong 3 and 4. In "trying
> to be informative", the only new information  that you contributed
> is that you know the web address of Goggle. BTW many housewives,
> construction workers and secretaries also know where to find Google.

Do they?  Not according to the guy I just saw on the news, plugging
tbo.com for hurricane information... ;-)

> > Alas, we have no "paraphrase marks" :-)
> 
> Your <paraphrase>markings for a paraphrase</paraphrase> included
> two completely backwards mis-conceptions. First. the OP was in
> fact using RF from his external box and not one of the other video
> inputs for his card. Second, he had not originally asked what the
> option was for. He had overlooked it entirely and did not know
> that this was the option that he needed.

Then I was misinformed.

> > I guess it was those "multiple promptings" that I missed out on.
> 
> That would be consistent with your having not read the thread
> and only commenting on the basis of your impressions. In his first
> posting he was concerned about keeping the tuner on channel 3
> which meant that he must have been using the tuner input. I then
> asked him in two messages to verify this just to make sure we
> were on the same page. When he confirmed this he said <paraphrase>
> he thought it didn't matter</paraphrase> which tells me he was
> unaware that the different types of inputs were not equivalent
> and the preset channel issue was unique to the tuner input.

Clearly, that would be the case.

> >>>Cause that's what *I* thought he was asking about.
> >>
> >>I have to admire your willingness to at least admit here that
> >>you were wrong. Perhaps if you read the actual text rather than
> >>making up your own quotes you wouldn't make these mistakes.
> > 
> > Indeed.  And for that, I apologize.  My snap reaction to his posting,
> > as I think was true for others, was "it's supposed to already be doing
> > what I think you're saying you want, Matt; what's up?"
> > But clearly, I missed the boat a little.
> > How nice, that we all have you here, Bruce, to keep us in line.
> 
> Not a problem. Glad I could help.

:-)

> My primary concern is that I want to have the best DVR system
> possible. As a result of Matt's misunderstanding of the option
> and a related thread a day or two later, I did update the help
> text to hopefully help others better understand the preset channel
> option in the future.
> 
> If you'd like to direct your energies to contribute more to the
> project than just trying to show off how smart you are (or show
> off how smart you are by contributing code and documentation ;-)
> I'm sure those efforts would be appreciated.

Well, I'd be glad to turn some of the terse technical answers I am
*not* receiving to the query I posted last week... if I'd gotten any.

Cheers,
-- jra
-- 
Jay R. Ashworth                                                jra at baylink.com
Designer                          Baylink                             RFC 2100
Ashworth & Associates        The Things I Think                        '87 e24
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	"You know: I'm a fan of photosynthesis as much as the next guy,
	but if God merely wanted us to smell the flowers, he wouldn't 
	have invented a 3GHz microprocessor and a 3D graphics board."
					-- Luke Girardi