[mythtv] [mythtv-commits] Ticket #3418: [13136] prevents seeing channels with duplicate callsigns

Daniel Kristjansson danielk at cuymedia.net
Mon May 7 23:03:44 UTC 2007

On Mon, 2007-05-07 at 13:59 -0700, Bruce Markey wrote:
> Daniel Kristjansson wrote:
> > On Sun, 2007-05-06 at 13:17 -0700, Bruce Markey wrote:
> >> Michael T. Dean wrote:
> >>> On 05/06/2007 02:01 PM, MythTV wrote:
> >>>> #3418: [13136] prevents seeing channels with duplicate callsigns

> Back to CNN. This is a network that is sent to affiliates.
Ok, I got ya. The callsign in this case refers to the network
stream, and each affiliate uses the same callsign; but modifies
the stream as affiliates do.

> However, I
> infer that you intended to say something like 'the content from
> the station is identical for every channel that carries the
> station'.
What I meant was for WNET/WLIW the programming on
for example "WNET-HD" will be the same OTA and over CATV.
So in this particular case 'callsign' == 'content'.

> > The same is the case for the News Corporation, it has
> > 4 'stations' in NYC with different callsigns:
> >  WNYW     5.0 (5  VHF analog)
> >  WNYW DT  5.1 (44 UHF digital) and 9.2 (38 UHF digital)
> >  WWOR     9.0 (9  VHF analog)
> >  WWOR DT  9.1 (38 UHF digital) and 5.2 (44 UHF digital)
> I agree that frequency != callsign. I disagree that frequency !=
> channel. A channel is the frequency (or ID) for a receiving
> device to 'tune' to in order to receive a broadcast signal. The
> origin of the programming that is broadcast over that frequency
> (if any) is a different issue. Two or more channels may carry
> programming from the same station and that programming may be
> identical but they are still two (or more) different frequencies
> which the receiving device may tune to. 9.0, 9 VHF analog, 9.1,
> 38 UHF digital, 5.2, and 44 UHF digital are six examples of
> channels. If I tried tuning devices to these six channels in
> southern Nevada, most would have snow or no signal and none
> would show WWOR content but the receiving device could be
> instructed to tune to that carrier frequency. Therefore, each
> frequency is a channel (regardless of the content sent over
> that channel).

All I meant was that the transmission on a frequency can be a
multiplex carrying more than one "channel of programming"; the
frequency UHF 44 contains the set {5.1,5.2}, while the 5.1
"channel" contains the set {5.1}, and {5.1} != {5.1,5.2}. The
frequency UHF 44 is an "FCC channel", but corresponds to two
"channel" rows in MythTV with different tuning information.
Should I refer to 5.1 as a "sub-channel" rather than a channel
to avoid confusion?

> My point is that we fall into the trap of saying that 'IFL
> Battleground is on 9' and '9.0 is the exact same channel'.
> Well, it is WWOR that broadcasts IFL and tuning an NTSC device
> to channel 9 in New York should show the WWOR content. 9.0
> would be entirely different tuning information for an HDTV
> device to determine which packets to decode in order to see
> the content sent from WWOR.
I grok you completely on this.

> Second, she is only recording IFL to be able to converse with
> her boyfriend. Dancing With the Stars must, of course, record
> in HD on her only HD card and therefore it is okay for the Single
> record rule for the IFL event to use 1009 on an NTSC card to
> capture the same programid at the same start time from a WWOR
> broadcast.

> A suggestion was made that the callsigns should differ but that
> will affect schedule decisions. I suggest that the callsigns
> should remain the same but use a different cosmetic channel.channum
> so the EPG will show two rows and as a visual aid everywhere to
> clue you in on which channel (fre...) is being referenced.
This is a sensible way to do things; we should do this
in the mythweb as well.

> > Second, manual recordings should be based
> > on the channel not the station (currently if you create a manual
> > recording selecting "1071, WABC-HD" and MythTV has a "7-1
> > WABC-HD" you can end up with the wrong one being recorded.
> > (I ran into this with a couple FTA DVB-S channels, one without
> > listings, the other day.)
> This is a little fishy. Manual record rules can, do and should
> behave like rules that match showing in the listings. If two
> channels are given the same callsign, we should assume that the
> content is predominately the same. If that is not true then change
> the callsigns. Therefore the manual timeslot for either WABC-HD
> channel should grab the same content. However, it is possible
> in a rare exceptional case that the manual rule is for content
> only shown on one of the channels and not the other but is not
> shown in the listings. In that case, the preferred input can be
> set in the rule's Scheduling Options to force which input should
> be used. The ability for the majority of manual rules to failover
> to another channel from the same station should not be sacrificed
> for this rare exception.

I'm fine with this. If you have no listings data for a
channel you either need to give it its own callsign or
create a preferred input rule. (This happened to me
with a partially configured machine anyway, I hadn't
set up DataDirect yet for the source I wanted to record
from; hence the manual record rule.) The argument
against this of course is that if you are using manual
record you probably have listings problems. But this
could be solved with a specific check to see whether
the channel has programming info, and modifying the
record rule in the case of no programming info to add
an input preference by default; I'm happy to consider
that a feature request and not think about it again
unless someone writes a patch.

> > I also have to change those smarts I just added in the multirec
> > branch to check that the current programs are identical before
> > substituting one WABC for the other WABC when the desired one
> > of them is on an unavailable tuner and they have a different
> > channum, I thought that 'callsign' == 'programming stream
> > aside from commercials' in MythTV.
> Right. This is part of the thought that I don't care what CNN
> is broadcasting from Atlanta GA, what I need to know is what
> Cox cable 20 will be showing from CNN. Regardless of if callsigns
> are the same, different or similar, we need to know what specific
> shows to expect when we tune to a specific channel(!). On Sunday
> evenings, I've needed a program entry for 1003 (3 KVBC), 10pm,
> "The Apprentice". Another row for 2123 (123 KVBC) that tells me
> that sending 123 to the channel change script then recording from
> s-video would also capture "The Apprentice" from this NBC affiliate.
> However, a few hours earlier I could only record Ebert & Roper
> from 1003 but I could have recorded Nevada Newsmakers on 123 at
> the same time from an s-video input.

Makes sense. I just hadn't thought about it this way
before yesterday because all channels I get from various
sources have the same programming when the callsigns are
identical (only the commercials differ). But obviously if
I had both DishNet and CableVision CNNHN would probably
differ because first is a national (or at least East coast
feed), while the other is a regional feed.

-- Daniel

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