What is a QAM user?

What is a QAM user?

Postby faginbagin » Sun Sep 28, 2014 2:06 pm

I am trying out the mythtv JSON grabber and am confused by the instructions found here:
https://github.com/SchedulesDirect/mfdb ... I-20140530
specifically the definition of a QAM user.

WideOpenWest is my cable provider, I use only clear QAM, I do not have a cable card tuner, and it looks like the correct lineup for me is USA-MI58783-X. I thought I was a QAM user, but I no longer think so, because:
- There is no lineup that ends in -QAM available for my zip code.
- When I look at the channel table populated by sd-utility.php, the mplexid values are all 32767 and the dtv_multiplex table is empty.

Perhaps the README.md could be more clear on what is meant by a QAM user?

I am testing on a newly installed/updated mythbuntu 14.04 system runninf mythtv 027-fixes. So, no video sources existed before today and no previous channel scans have been done. I've got a production system that uses the current XML service and mythfilldatabase and did not want to risk breaking it, but I though I might be able to help prepare for the future with a spare machine.

FWIW, my next steps are to:
1) Mark as invisible all the encrypted channels I can't get
2) Do a channel scan via mythtv-setup.
3) Try once more to do an Update via sd-utility.php

If that all works and I have listings, are you interested in my tuning data? If so, do I use "sd-utility.pp --extract" or the instructions found here: viewtopic.php?f=3&t=1211?

If "sd-utility.pp --extract" is the correct approach, then why does the README.md direct me to viewtopic.php?f=3&t=1211?

Confused (and hoping to help the next user),
Helen
faginbagin
 
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Re: What is a QAM user?

Postby rkulagow » Sun Sep 28, 2014 4:23 pm

OK, so a QAM user is one where we have a QAM lineup, and that means that we've received a channel scan from someone. For you, it appears that we haven't.

If you look, you'll see that one of the options in the MythTV portion is "Extract". That will take the channel scan that you performed in mythtv-setup and create a file that can be sent to us. If you run --help, you'll see that there's a dedicated extract command as well.

What we're trying to avoid is the "classic" issue with QAM - you run a scan in mythtv-setup, then you need to link the scanned channels with XMLTV stationIDs, either by watching each channel live until you can figure out what it is, or using SCTE/65 (if it's available as a hint).

We will take a raw scan, process it, do the correlation, and then create a QAM lineup for the user. If you're the first / only user, then there's a little bit of a lag, and there may be some back-and-forth as we get things figured out. If you're the _next_ user, or you have to rebuild your system in the future, then there's already a QAM lineup available for you. No scanning necessary, because the QAM lineup you download will already have the correlation between the QAM data on your coax and it will put the correct frequencies, etc, into the appropriate tables in MythTV.

Is that a little clearer?
rkulagow
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Re: What is a QAM user?

Postby faginbagin » Sun Sep 28, 2014 8:31 pm

That does seem to confirm what I had guessed. But I'm still confused about one point. I asked in my original post:
If "sd-utility.pp --extract" is the correct approach, then why does the README.md direct me to viewtopic.php?f=3&t=1211?

Also, given that I cannot tune encrypted channels since I don't have a cable card tuner, are you interested in my tuning data?

FWIW, I do know of one other user who could use that data, my sister.

Regards,
Helen
faginbagin
 
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Re: What is a QAM user?

Postby rkulagow » Mon Sep 29, 2014 9:18 am

I've updated the README to make QAM slightly clearer, I hope.

Now that the extract functionality exists, we don't need to use an external script.

Thanks for the reminder.
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