mythtv-setup can't scan DVB-S

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realh
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mythtv-setup can't scan DVB-S

Post by realh » Tue May 29, 2018 11:48 pm

I'm trying to set up an Ubuntu 18.04 PC to receive Freeview and Freesat. I'm using mythtv-setup. The Freeview scan worked, but no matter what frequency and parameters I enter, it won't scan on the satellite card. It says "No new channels found", but I don't believe it's even trying, because (a) it gives the same response even if I enter a nonsensical frequency and (b) it did much the same thing when I tried it before a few months or years ago, except the error message was something about invalid parameters. It also keep crashing on another occasion I tried to use it, so I assumed the database was corrupt and deleted it before I installed it this time.

On those past occasions I switched to tvheadend, but I can't stand it any more, so I'd rather spend my time getting mythtv working. I think my best bet, unless I've somehow missed that mythtv-setup has been replaced, is to write a script that converts a file from some other scan tool to mythtv-compatible SQL. Does such a thing already exist? If not, is there a guide to mythtv's database structure, hopefully with helpful comments?

MikeB2013
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Re: mythtv-setup can't scan DVB-S

Post by MikeB2013 » Wed May 30, 2018 7:06 am

You don't mention mythtv version and the brand name of the DVB-S/S2 satellite card.
As you are on Ubuntu 18.04 I am assuming mythtv 29 from the Ubuntu repository or from ppa:mythbuntu/0.29 (this keeps mythtv up to date, the version in the Ubuntu repository is a snapshot which is not likely to get updates).

I have a test system with Freeview (TBS 6280 dual DVB-T/T2) and Freesat (TBS 6981 dual DVB-S/S2) tuners on Xubuntu 18.04 running mythtv 30 built from source from (although newer than mythtv 29 there is little if any difference in channel scanning). Note I am not suggesting you upgrade to mythtv 30, as this is the development version and is therefore subject to breakage.

There are a few niggles at present with mythtv-setup on Ubuntu 18.04 (and others) which mean you need to run all mythtv-setup commands from a terminal session. You may be aware of these but just in case.
mythtv-backend must be stopped before using mythtv-setup and started using the appropriate systemctl command:
To stop mythtv-backend use "sudo systemctl stop mythtv-backend"
To start mythtv-backend use "sudo systemctl start mythtv-backend"

To find out your mythtv version run "mythbackend --version" in a terminal session.
To see what tuners have been created run "dmesg | grep frontend" in a terminal session.

In mythtv-setup:

Capture Card:
I have:
Signal timeout 7000
Tuning timeout 10000
Wait for SEQ start header ticked
Open DVB card on demand unticked
Use DVB card for active EIT scan ticked (if using external program data e.g. Schedules Direct this should normally be unticked unless you have a mixture)
DiSEqC (Switch, LNB, and Rotor Configuration) set to LNB (depending on theme you may have to scroll to see this)

The Freesat tuning parameters I use for my TBS 6981 tuner are:
Frequency 10714000
Symbol Rate 22000000
All other parameters are at default

Note if after running channel scan you are still getting no channels check dmesg output it may show issues with firmware or tuning.

realh
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Re: mythtv-setup can't scan DVB-S

Post by realh » Wed May 30, 2018 12:40 pm

Ah, it was the DiSEqC option that was the problem, mine was still "Unconnected". It seems to be working now. Thanks for your help.

I might as well give the other details. Yes, it is the official Ubuntu 18.04 package. Would you recommend using the mythbuntu PPA instead? I usually prefer to use the latest versions of most software, within reason, rather than assume an old version is more stable. But the reason I use Ubuntu on that box is to avoid having an extra machine to do frequent updates on, so if the mainstream package (currently 2:29.1+fixes.20180414.32) is OK once set up, I might as well stick with that. Although I did read something about DASH support being in the pipeline, and that would be nice.

I think my tuner is a TBS 6922, it's a single tuner PCI-E card.

MikeB2013
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Re: mythtv-setup can't scan DVB-S

Post by MikeB2013 » Wed May 30, 2018 2:16 pm

Personally I would use the mythbuntu ppa to keep up to date, I also prefer running the latest stable version.

There have been a few changes since the version in Ubuntu repository, as time goes by the differences will get greater.

Fortunately it is easy to use the ppa, so in your case just run in a terminal session

sudo apt-add-repository ppa:mythbuntu/0.29
sudo apt dist-upgrade

I would then reboot, not strictly necessary but I prefer a clean start after updating (adding a ppa in Ubuntu 18.04 automatically does an apt update, so any other pending updates will be pulled in).

Note the apt dist-upgrade is normally only needed when going from one version of mythtv say 29 to 30 (when it is released) to the next, but it does no harm. This has caught out a few people in the past when upgrading.

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