[mythtv] [mythtv-commits] Ticket #2965: ATSC QAM256 channels fail to tune (partial lock) that are working channels with xine and vlc

[Jerry Rubinow]

On 1/22/07, Daniel Kristjansson <danielk at cuymedia.net> wrote:
> On Mon, 2007-01-22 at 20:10 -0500, Jerry Rubinow wrote:
> > On 1/22/07, Daniel Kristjansson <danielk at cuymedia.net> wrote:
>
> > And I can configure my firewire input to use the same
> > channel lineup, and everything's good.
> I don't think this is a good idea. Firewire uses the freqid
> to tune, but this is only set for completeness in a QAM scan;
> and for the DVB card this is the actual frequency in a frequency
> table, while for the firewire card it is what gets sent to
> the channel changing script or is used by the internal channel
> changer as the channel to send to the STB.

Hmm.  What's the proper way to set this up then?

How does myth figure out which analog tuner to use when two analog
tuners share a lineup?  Or I guess the more general question is how
does myth figure out which tuner to use in general when two tuners
share a sourceid and you change to a channel they both share?  It
works properly for two analog tuners, but you're saying it may not
work when a DVB and firewire tuner share a sourceid.

I was thinking that for DVB channels, myth uses the mplexid and
serviceid for tuning, and that for firewire it uses the
atsc_major/minor numbers or freqid.

Hmm.  One difference I see between the two analog tuners case and the
firewire/DVB case is that for the analog tuners, there's only a single
instance of a given channum.  While in the DVB/firewire case, there
are two different chanids which share a channum.  I can understand how
myth could be confused by the second case.  Is it possible that if I
collapsed the two chanids into one, which had both the freqid,
mplexid/serviceid and atsc info, that myth would be able to deal with
it?

> channums are not used for tuning with either recorder, these
> should not have an effect. How exactly are you renaming the
> channels?

On my first attempt, I used the wiki instructions of watching live,
pressing E, putting in the XMLTVID, and hitting Probe.  The very first
time I did this it worked.  But then later when I rebuilt my DB from a
clean slate, configuring new cards and inputs, that resulted in things
not working right.  That's when I tried starting with tweaking the
channel table entries experimentally.  I tried a lot of different
things, it was late, memory hazy.  My incomplete knowledge of how myth
does the tuning made it hard to figure out and frustrating.

> I think the XMLTVID is a red herring. I will get my DVB setup
> working again tonight and try to to reproduce this. It might
> be related to #2394, or it could be something new.

My process was as follows:

1. drop mythconverg
2. run mythtv-setup
3. configure the DVB card, then the firewire card
4. Setup the channel lineup.
5. Setup inputs, setting both cards to the single lineup.
6. Scan channels in the DVB card.
7. Mythfilldatabase -do-channel-updates
8. Startup myth
9. Watch TV
10. Switch to DVB tuner.
11a. Hit E, enter XMLTVID, Probe, repeat.
11b. Alternately, instead of 11a, edit the DB and manually put in the
XMLTVID and a channum that matches the equivalent firewire channum.
12. Run mythfilldatabase again.
13. Enter live, tuning doesn't work.  Or it does.  Possibly related to
which tuner was initially configured first?

On a related note, how does myth decide which tuner to use when you
first go into live tv?  I would have assumed it would use the
priorities, but this doesn't seem to be the case.

-Jerry