Intermittent Tuning Problems

[paul.mcguire@live.co.uk]

Hi, I've just set up a new install of libreelec with NextPVR server and client on an intel NUC with two USB tuners. I am getting very intermittent behaviour with channel switching and recording. Errors seem to be either:

2023-04-26 13:34:47:299 [INFO] Tuning: 474167000 Hz
2023-04-26 13:34:47:299 [ERROR] dvb_fe_set_parms failed
2023-04-26 13:34:47:299 [ERROR] Failed to start stream

or 

2023-04-26 14:31:00:168 [DEBUG] waiting for signal lock
2023-04-26 14:31:06:995 [DEBUG] status 00 | quality 00 | signal ffff7b30 | snr 7530 | ber 00000000 | unc 00000000 | pre_ber 00000000 | per 00000000 |
....repeated  then
2023-04-26 14:31:07:021 [ERROR] Failed to start stream

(log attached)

Sometimes it will work fine other times after a few channel switches it gives up and fails to work. Sometimes one tuner works and not the other. Once it has managed to tune it seems to work ok though I can record one mux and watch another with no apparent signal problems visible.

Any thoughts would be much appreciated, would love to get this working.

[mvallevand]

Certainly that second one is signal related which can be temporary. There were bugs before on the parms but I think those have been fixed but you can check journalctl for driver errors. The quality of tuners on Linux varies dramatically, Windows driver are almost always more reliable.

Not much we can do based on just snippets though. Zipped NextPVR logs after a problem would be recommended.

Martin

[paul.mcguire@live.co.uk]

Thanks for your quick reply. 

I think it is only when using both tuners. Seems to be ok if I open a web interface on windows and repeatedly switch between channels, but when I try to record something at the same time it then fails. Also fails if I open a second web interface and try watching two channels at the same time.

Logs attached (I think).

[mvallevand]

Logs need to be zipped and under 2MB. Otherwise post them on an cloud storage somewhere.

Martin

[paul.mcguire@live.co.uk]

Sorry I seem to be having trouble attaching logs
I get "your allocated attachment usage quota is NaN MB."

[paul.mcguire@live.co.uk]

ok logs here

https://1drv.ms/u/s!AnwMMbw9wwuIibwXh_yosrcLcvL9Mg

Appreciate your help..

[mvallevand]

Thanks, given how often how BBC ONE South is failing, I think that one is probably signal.

I did see two instances where you where doing an OTA EPG update and it looked like you tried to watch Live TV or record on the same tuner milliseconds after the EPG might be finishing up. The logs don't go back far enough to tell if it even finished. If you watch or record a lot at 02:45 maybe change the EPG update time.

Martin

[paul.mcguire@live.co.uk]

I unplugged one of the tuners to eliminate the dual tuner set up. I restarted everything and then tried repeatedly changing channels, approx 1 in 8 attempts it just wont tune and you get an error. Retry and it works again. This is quite repeatable.

When it does tune in it works fine and plays reliably.

I tried repeatedly switching channels but staying on the same mux and this seemed ok after a lot of changes.

It does seem like it's to do with the initial tuning operation.

[mvallevand]

I don't think it has anything to do with the dual tuners they both seem to experience the same problem.

There were failures to the lock in the logs you provided staying on the same mux and changing the mux

I personally don't think it is NextPVR but you can always try TVHeadend. It doesn't use libdvbv5 and you might have more luck. Sub would have to comment on the tuning logic.

Edit: I see on the LE forum that you have the same problem with it. I rest my case. You could trying keep the tuner primed (always on) to see if constant power helps.

Martin

[paul.mcguire@live.co.uk]

yes TV headend has the same problem. I would not rule out signal issues it just seemed odd that when it tunes it works fine without a single glitch and all my tvs work fine, kind of implying the signal is ok.

Whilst not a nextPVR problem, I was hoping maybe someone had similar issues and there was some workaround. I'm still stuck as to what to do next. I did try the keep primed thing it didn't help.
Ta.

update - 

I have now installed nextPVR on Windows and connected the same USB tuners, no problems at all seen so far, so I'm thinking it must be an LE/driver issue. No idea how to fix it though.