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

[Daniel Kristjansson]

On Mon, 2007-01-22 at 20:10 -0500, Jerry Rubinow wrote:
> On 1/22/07, Daniel Kristjansson <danielk at cuymedia.net> wrote:

> I'm currently having a very difficult time trying to get a DVB tuner
> working properly and I'm wondering if it could be related to this or
> changeset 12618.  I configured an AverTV HD A180 configured and
> scanned the channels and am able to tune properly - with all the
> channels still in the 71#1 type format in the database and to
> XMLTVIDs.

> 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.

> However, when I try to map the
> channums of the DVB scanned channels to the equivalent channums in the
> firewire, it stops being able to tune them, with partial lock
> messages, etc, similar (apparently) to what Wylie mentioned.

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

> Oddly, I can revert to an earlier incarnation of my database, and they
> play happily together.  But when I remake my card and inputs from
> scratch, I run into problems.  I'm running trunk SVN from earlier this
> month.  Does it sound like it might be this or some other bug, or does
> it sound more like I'm screwing something up?
The only thing I can think of is that there used to be a bug
in the firewire recorder where it used the channum for tuning
instead of the freqid; but these are equivalent in the example
you give below, so it shouldn't matter.

> To give an example, for a DVB chanel, I have chanid 2711, channum
> 71#1, freqid 71, sourceid 2, mplexid 17, serviceid 1140.  And for the
> equivalent firewire channel, it's chanid 2810, channum 810, freqid
> 810, sourceid 2, atsc_major 810, atsc_minor 0.
> This will tune ok to the DVB channel if I go into live tv, and hit Y
> to select the DVB tuner.  However if I change channum to 810 and set
> the XMLTVID to be the same, I start getting the partial locks when I
> go into live tv and try to tune the DVB channel.

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.

-- Daniel