[mythtv-users] Stability of FE/BE combos?

[James Abernathy]

On Wed, Jul 15, 2020 at 12:08 PM Stephen Worthington <
stephen_agent at jsw.gen.nz> wrote:

> On Wed, 15 Jul 2020 09:09:30 -0400, you wrote:
>
> >Since I'm retired and forced to stay home a lot due to Covid-19, I've been
> >experimenting with a bunch of media software to learn and stay busy.
> >
> >My production backend is Mythtv v31 on Ubuntu Server 18.04 with a UPS
> power
> >backup.  It is stable as a rock. Only gets rebooted when updated.  I do
> >find that my Shield TV running Mythfrontend, Leanfront, or Kodi is mostly
> >stable but occasionally fails and I have to restart the app, hardly ever
> >having to reset the Shield TV.
> >
> >I've been testing combos on RPi4 and old PCs and find the frontends fail a
> >lot more than I find acceptable. And since I can't fix the frontend
> without
> >resetting the whole combo I can lose recordings.
> >This seems to be true with Mythtv v30 and v31 and it's true with LibreELEC
> >TVHeadend.
> >
> >My biggest issues seem to be screen freezes, and the combo forgetting it's
> >resolution for the TV when the TV is powered off at night. With the combo
> >on a PC, I can ssh in and restart lightdm and that sometimes fixes the
> >resolution issue.  However, on Raspbian or LibreELEC I find rebooting is
> >the only way out.
> >
> >So I'm wondering if this is similar to other's experiences?
> >
> >I don't think I could ever use a combo FE/BE in production based on my
> >experiences.
> >
> >JIm A
>
> I have an FE/BE system.  With my old Nvidia GT220 card, it was
> completely solid for many years.  When I upgraded to the GT220, I had
> a couple of driver lockups that went away as Nvidia fixed the drivers.
> After that there was around 5 years with no troubles.  Since I have
> changed to an Nvidia GT1030 card, I do get occasional video lockups
> again.  I did nave a couple where the entire PC stopped, so I updated
> the Nvidia drivers to the 440 series from the PPA and that is better.
> I have had one video lockup since, but the backend was still fine and
> recordings kept happening.  I was able to restart the desktop using
> Ctrl-Alt-Backspace (which I had re-enabled many years ago).  This
> feels like Nvidia driver bugs again - it only happens when I am
> playing a recording or a video.
>
> The other problem I have occasionally is with the DVB-S2 tuners - they
> are used for my satellite pay TV service, and occasionally the
> software doing the decryption from my pay TV card does something
> strange and restarting it does not fix it, so I have to reboot.  This
> one feels like a software bug too, and as I have most of the source
> code I do hope to find the time some day to work out the exact
> problem.
>
> My mother's old FE/BE MythTV box was even more reliable than mine.  It
> had an ancient Nvidia card builtin to the motherboard.  It only ever
> got rebooted for kernel upgrades.  Unfortunately, a few weeks ago it
> started to crash every night after she had been watching a recording
> for about an hour.  Given that the motherboard was over 11 years old,
> it was not worth trying to fix it, especially as it had only 4 Gibytes
> of RAM and Nvidia no longer provided drivers for the builtin video, so
> it could not be upgraded past Ubuntu 16.04.  And it was swapping a lot
> too - MythTV has grown quite a lot over the years.  I thought it was
> probably a thermal hotspot developing on the CPU somewhere - the
> thermal paste breaking down.  So it has been replaced with a new
> motherboard and is using my old GT220 card, and we are hoping for
> another 11 years.  It has not had any problems in the week it has been
> running, and the upgrade meant I could add two of my old DVB-S2 tuners
> to it and give her the satellite service as well.  And MythTV showed
> just how good it is - it instantly found a new series of "The
> Durrells" to record for her from the satellite.  She was very pleased.
>
> So my story seems to be that the video drivers are the thing that
> causes serious problems.  That seems to be the case for a lot of
> people.  Life would be much better if we had open source drivers that
> we could fix ourselves - Nvidia do not always fix things.  And these
> days they are abandoning the older chipsets at an alarming rate.
>
> BTW The resolution problems can normally be fixed by an xrandr command
> from a terminal on the desktop.  I have not yet set up my xorg.conf to
> prevent the use of my TV's interlaced modes and since changing to a
> GT1030 I often get the TV going into 1080i mode, which is a pain as
> the text does not display properly.  It is fine for displaying 1080i
> recordings, of course, but I would prefer that the TV stayed in
> progressive modes and the Nvidia card did the deinterlacing, so that
> the text MythTV displays (for the I key, for example) displays
> properly.  At the moment, I just Alt-Tab to a terminal and run 'xrandr
> -r 52" which reselects 1080p mode and everything is fine again, until
> I stop playing the recording or do some other screen change such as
> Alt-Tab.  Working out the -r number to use seems to be a matter of
> trial and error.  I tried -r 52 as the native refresh rate of the TV
> is 50 Hz, so the correct number was likely to be 5x.  For a 60 Hz
> screen it is likely to be 6x.  Fortunately my TV displays the mode for
> a couple of seconds when it gets changed, so it was quite easy to see
> when I had found the right mode.
>
> It seems those with stable combo FE/BE are using PCs with NVidia GFX
cards.  My biggest issues are with RPi4.

I hate to use a PC as a Combo because there's a lot of heat and power near
my TV.  I've grown fond of the quality of my Nvidia Shield TV as a FE
because not only does it run Kodi, mythfrontend, and leanfront very well,
it also does a wonderful job on Netflix, Prime VIdeo, etc.

I've had good luck with backend only solutions on the RPi4 including
comskip or mythtv commflag. Any use of the RPi as a frontend has been poor
at best, even for Kodi which is usually pretty good.

I'm going to run a long term stability test of a RPi4 with Raspberry Pi OS
and mythtv backend and see how long it stays up.
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