Confusion of Tuning/delay/timeout settings in Kodi/MythBackend
#1
Hi, I'm hoping someone can help me understand a couple of things. Previously i was getting a number of issues when changing channels, either very slow channel changes or the "channel not available" message. I posted a question within the PVR.MYTHTV add-on thread [http://forum.kodi.tv/showthread.php?tid=...pid2019077] and updated to a new version as advised.

After doing that, i didn’t get any "channel not available messages" but it was taking nearly a minute to change channels, I then decided to fiddle [!] within the add-on i reduced the tuning delay from 20 sec to 15 sec, and now I get channel changes of ~1-3 seconds (a reasonable time).

Would someone help me understand what all the [below "Tuning/delay/timeout "] settings mean in both Kodi & Myth Backend please (i've searched Kodi wiki & various Myth documents and it hasn't really answered my questions) ..

So for example, I would of thought "Tuning delay" means it delays tuning the channel for 15 secs, but it clearly can't, if I’m able change a channel now with in 1-3 secs... so what’s it's delaying? also Time Out in the Kodi Live TV settings, when channels was taking 60 secs to change i would have thought it would have timed out using a 20 sec value? but it didn’t

The good thing is it's seems to be working now, i'm just not too sure how! and i would really like to understand why....


Tuning/delay/timeout settings in Kodi/MythBackend

Kodi Live TV setup

Timeout when starting playback: set at: 20 sec - is this the same as the Mythbackend which value is used if they are different? the one i set in Kodi or the MythBackend?

Delay channel switch: set at 0.75 - I think this delays showing the "info panel" before the channel is tuned?

Add-on-settings

Tuning delay (sec) : set at: 15 sec (originally 20sec) - is this the same as the Mythbackend which value is used if they are different? the one i set in Kodi or the MythBackend?

Myth Backend config

Under capture cards > Recording options:

Signal Timeout (msec) = set at: 20,000
Tuning Timeout (msec)= set at: 20,000
Tuning Delay = set at: 0.75 (I’m not even sure, if i need to delay tuning on my card (it's a TBS6905 - quad DVBs)


Any answers gratefully received, happy to also enrich the wiki on the back of this....
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#2
I run both kodi and mythtv-backend using the defaults, with no problems. The only time I would expect to increase timeouts for dvb-s is where a motorised dish or some other satellite switch is being used.

I do not see why changing pvr.mythtv Tuning delay from 20 seconds to 15 seconds would speed up channel changes, my 0.27/4 fixes mythtv-backend with kodi 14.2 Helix pvr.mythtv 1.12.20 test system does not display this behaviour. All my channel changes are in a few seconds.

Kodi pvr.mythtv addon

Tuning delay in Advanced tab defaults to 5 seconds, and is the maximum time the addon will wait for a good channel change response from mythtv-backend, Unless there is good reason leave at 5 seconds, which is usually more than enough for dvb.

A higher value should have no impact if channel change is good, but will if the the channel is bad for whatever reason.

The pvr.mythtv addon will try all possible tuners when a channel change fails, so if you have 4 tuners, each with multirec set to 2 (in mythtv-backend), the maximum time to would be 8 x 5 = 40 seconds before kodi fails the channel change.


mythtv-backend

I have TBS 6981 dual dvb-s/s2 card which uses the defaults

Default Signal timeout is 7000
Default Tuning timeout is 10000 -this is used to timeout channel lock when changing channels

Again leave at defaults, unless you have good reason to change.

For dvb-s/s2 the actual channel change time is usually less that 1 second, but does take a little more to propagate through the system to your TV screen.

Tuning delay is rarely used these days and should be at default.

Mike
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#3
Thanks Mike for the confirmation, after doing some additional tests this evening, I now believe reducing the value of the tuning delay in the addon-on and the reduction in time to change channels was a coincidence.

I still have a problem when a scheduled recording has completed.... During recording everything is perfect, channel switching stays with in the ~1-3 second range. However once the recording has completed, the time it takes to change channels dramatically increases. It's not until I reboot, the channel changing reverts back to normal... I've got a feeling a log will be needed to understand what's going on, to which I will provide when I get some time...

Thanks again...
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#4
Ok I have this, http://xbmclogs.com/pql02necn, [i hope I have done this correctly, im affraid it's a little big] I turned on debugging and also debugging on the addon.

For this test, I truned on live TV, started a recording on another channel, watched another channel, waited a couple minutes changed channels a couple of times (everything ok) waited until recorded programme completed, then changed channels, changing channels now take ~20 sec or finally came up with the channels can't be found message.... Rebooting solves the issue and channels switching is back to normal...

Thanks in advance..
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#5
From the log you are running a very old version of mythtv 027/fixes, from March 23 2014

You need to upgrade to the latest version of mythtv 0.27/fixes

The easiest way to do this is from a terminal

sudo apt-add-repository ppa:mythbuntu/0.27
sudo apt-get update
sudo apt-get dist-upgrade
sudo reboot

Mike
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#6
Mike, thank you so much, it works, I've been battling with this over the last 3 months, it such a relief!!!
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