Building a MythTV PVR

Epilogue - 3 years on

It is now spring 2019. How has it gone?

Pretty well, all in all. It is still the main method I have of recording off air TV programmes (although I have written a similar backend of my own for Linux in C++).

Mythbuntu seemed to die a death, although I just recently noticed there is now a Mythbuntu 16.04 on the web, so I assume it is back alive again. Probably I should reinstall from scratch using that, but it was such a faff getting it all going in the first place that I just cannot face it. Probably if I were to do something like that that I would base it on the latest LTS Ubuntu at the time of doing it, but use my own backend, not MythTV's one. Whilst it is less generally capable than MythTV - and I have never written a Kodi PVR add-on for it, it does do a few things that I specifically want.

At the end of the day, it is a tool to use, not a development project, so I am not inclined to change it until it ceases to do its job in some significant way. There are problems with it, but not major ones:

• Occasional failure to boot up (once every few months)
• Occasional failure to start Kodi (once every few months)
• Database table corruption

The failure to boot seems to have been dealt with by setting the boot loader to retry on a boot failure. Haven't seen that issue for a long time now.

The Kodi failure does occur. It does not stop the backend starting up, but since it will not shut down unless Kodi is running, once booted, it stays booted. This is still running Kodi V15, and I guess it should really move to a later version.

The database table corruption occurred once. It was just one table and the consequence was total failure to store any event information, and therefore inability to set a recording from the EPG. It was fixed by using raw SQL to remove and replace the table. I later found that Mythweb does have a table check and repair function so that might have been an easier way to do it. However - one does not want it to happen in the first place.

I thought the most likely cause was a power outage at the wrong moment. Since we live in the country with overhead power lines, we do get an awful lot of short term (2-3 second) power dropouts, and probably - sooner or later - one of those would happen at an inopportune moment and cause the corruption. (As well as that of course, an outage while recording will ruin the recording). Therefore I invested in a small UPS - an APC BE700G-UK. I have not tested it, but estimate this would hold power up for 15-20 minutes.

The system, HD Homerun TV tuner and UHF aerial signal booster / splitter all run from the protected sockets, so this should allow it to continue over any short outage. Probably consideration of a longer outage is not necessary given that an unscheduled long term outage is very rare, but I did install the software to allow a graceful shutdown if the outage is so long the battery goes flat.

It does come with Windows software (Power Chute) but no Linux software. However, there is a generally available alternative for Linux - apcupsd. This was installed (USB connection) as follows (note all script editing must be done as administrator):

Download and install the driver via a terminal window:

I also installed udev:

but as that only offers hot plugging capability for USB ports etc, it was probably not necessary

Edit /etc/default/apcupsd, altering the line ISCONFIGURED=no to ISCONFIGURED=yes.

Edit the main configuration file /etc/apcupsd/apcupsd.conf, setting the following lines: UPSNAME <pick a name>, UPSCABLE usb, UPSTYPE usb and DEVICE <leave blank>. Everything else was left as default.

Check the installation by running apctest (also as administrator, and you may need to stop the service first if it is already running - /etc/init.d/apcupsd stop). There are also various command line, GUI and web utilities for checking its status.

There is some help for this on the internet, for instance https://www.cyberciti.biz/faq/debian-ubuntu-centos-rhel-install-apcups/ and http://www.apcupsd.org.