[mythtv-users] digital cable channel scan incomplete

[matt lutz]

On Thu, Dec 4, 2008 at 6:19 PM, R. G. Newbury <newbury at mandamus.org> wrote:

>  matt lutz wrote:
> > On Thu, Dec 4, 2008 at 3:44 PM, R. G. Newbury <newbury at mandamus.org>
> wrote:
> >
> >>  matt lutz wrote:
> >>> All,
> >>>
> >>> I've recently switched from DirecTV/OTA to digital cable.  I have a
> >>> HDHomeRun that I wanted to tune the ATSC channels with.  I've
> >> successfully
> >>> set up the new listings, the HDHR, and scanned for the channels.  I get
> >> the
> >>> local networks in HD, and some other odd news channels, but I don't get
> a
> >>> decent amount of the available content.  I've been able to map all of
> the
> >>> channels it does find to the proper channel # and xmltv ID, but the big
> >>> problem is the missing channels.
> >>>
> >>> If I use the HDHR windows app, I get all of them.  here is my listings
> >> page:
> >>>
> >>
> http://www.silicondust.com/hdhomerun/lineupui?Cmd=LocationProgramsWeb&Country=US&Postcode=22302
> >>> Mythtv doesn't find anything with a 'program' number of over 100 for
> some
> >>> reason.  I've searched all over the place on how to add new channels to
> >> the
> >>> database, and I've done what I think should be correct, but myth can't
> >> get a
> >>> good channel lock on the new channel I add to the db.
> >>>
> >>> Like I said, I know the HDHR can tune the channel, because I can get it
> >> on
> >>> my windows laptop using the HDHR software.  Does anyone have any ideas
> on
> >>> what could be wrong in my myth setup?
> >> It's not clear what you are actually adding to the db. What you need to
> >> add are: a) the frequency to dtv_multiplex and b) the channel info to
> >> the channel table.
> >> The *number* which 'everyone' uses for a channel now means basically
> >> nothing. And there actually are NO channel frequencies with a number
> >> over 100: those are just for convenience.
> >>
> >> There is page here:
> >>
> >>
> http://www.mythtv.org/wiki/index.php/Adding_Digital_Cable_Channels_(For_ATSC/QAM_Tuner_Cards_--_USA/Canada)
> >>
> >> which discusses this in some detail,
> >>
> >> If your hdhr can see it, then it can produce output which you can use to
> >>  set up your database. You really want to install the dvb-apps package
> >> to  start with. It's in Fedora 'Everything' but available elsewhere of
> >> course. Among other things it provides files listing frequencies and
> >> channel numbers:
> >> /usr/share/dvb-apps/atsc/us-ATSC-center-frequencies-8VSB
> >> /usr/share/dvb-apps/atsc/us-Cable-Standard-center-frequencies-QAM256
> >>
> >> Since these are ATSC OTA channels, you would use the first page and the
> >> azap program to scan for channels. Or you could just create entries in
> >> dtv_multiplex with numbers and frequencies.
> >> THEN you have to find the digital streams, and set up the PID and other
> >> info in the channels table. The wiki page describes this, and how to
> >> test using azap and mplayer.
> >>
> >> I suspect that you are trying to push into the database, the number
> >> which you would use in casual talk to describe a station, when its
> >> actual channel and PID are quite different due to the digital shift. The
> >> 3 networks in Buffalo used to be '2,4 and 7' and they still call
> >> themselves that, but those are NOT the tuning frequency channels they
> use.
> >>
> >> Finally, if you can tune some unknown channel in mythtv, and recognize
> >> it by its content against the guide you can use the on-screen editor to
> >> set the Name (WABC-DT) and XMLTVID, to match you Schedules Direct
> >> lineup. (But note: the xlmtvid is the definitive identifier at the
> >> SchedulesDirect end, but a tv station (or cable provider) and (and they
> >> do) change the frequency and/or PID of the digital stream whenever they
> >> damn well please!
> >>
> >> Geoff
> >>
> >>
> > Geoff,
> >
> > Thanks for the reply.  Sorry - I misspoke when I said 'ATSC', I really
> meant
> > qam256.  I do know the feqid and muliplex ID.  referenceing the hdhomerun
> > listings data, I'm trying to tune feqid 91, multiplex 108.  These are the
> > fields that I've entered into a new row in the database.  via mythtv, I
> > can't get a lock on it.  That goes for any channel that has a multiplex
> id
> > of over 100.  I'm not sure if that's just a coincidence or not...
> >
> > I should also add that I'm running mythbuntu 8.04 w/ mythtv 0.21, and I'm
> > trying to tune Comcast digital cable.
>
> OK. If your dtv_multiplex table has 108 entries, it has some duplicates:
> There are not than many actual frequencies...85 or 87 IIRC.
>
> Run Mythtv-setup  and delete ALL tuners on the second page to get back
> to zero. And use mysql if necessary to delete all entries in the
> dtv_multiplex table.
>
> Install dvb-apps and use azap and mplayer (its in the readme and the
> wiki) to scan your channels. You can also use the hdhr. For the hdhr you
>  can directly tune the unit with something like:
>
>  hdhomerun_config 1010ea43 set /tuner0/channelmap us-bcast
>   hdhomerun_config 1010ea43 set /tuner0/channel 8vsb:$1
>   hdhomerun_config 1010ea43 set /tuner0/program $2
>   wxvlc udp://@
>
> In your case it will be the cable channel-map and qam256 not 8vsb. This
> is part of a script I wrote and $1 is the channel by frequency number in
> the list, and $2 is the program PID. If you have vlc (wxvlc) installed
> you can watch tv with this.
>
> When you have a good list, use mythtv-setup to do a scan. Then adjust
> the information in light of what the hdhr has found. You need only
> ensure that the channel table has the correct dtv_multiplex frequency
> reference, and the correct PID (plus a couple of other settings,
> discussed on the wiki page).  The name and XMLTVID must match what
> SchedulesDirect uses for that channel per your setup at SD.
>
> Geoff
>
>
>
Geoff,

Again, thank you for the help.  I was able to tune my missing channel in
Myth, but maybe there's something wrong that needs to be fixed?  What I was
trying to do was tune the following channel:

freq - qam256:627000000
prog - 108

I didn't realize that the multiplexID in the channel table needed to
correspond to the frequency in the dtv_mutliplex table.  It makes sense now,
but there is a decent amount of conflicting information out there.

At any rate, I now believe I can manually map all of the channels that are
available by cross-referencing the hdhomerun data with the dtv_multiplex
table to get a good listing.  I guess I'm still a little confused as to why
the channel scan didn't turn up any of these SD channels.  perhaps I am
missing something....

anyway - thanks for the help.  You pointed me in the right direction.

Matt
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