Bradley M. Kuhn

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MythWeb Confusing Error Message

Sunday 13 March 2016 by Bradley M. Kuhn

I'm finally configuring Kodi properly to watch over-the-air channels using this this USB ATSC / DVB-T tuner card from Thinkpenguin. I hate taking time away, even on the weekends, from the urgent Conservancy matters but I've been doing by-hand recordings using VLC for my wife when she's at work, and I just need to present a good solution to my home to showcase software freedom here.

So, I installed Debian testing to get a newr Kodi, I did discover this bug after it had already been closed but had to pull util-linux out of unstable for the moment since it hadn't moved to testing.

Kodi works fine after installing it via apt, and since VDR is packaged for Debian, I tried getting VDR working instead of MythTV at first. I almost had it working but then I got this error:

VNSI-Error: cxSocket::read: read() error at 0/4

when trying to use kodi-pvr-vdr-vnsi (1.11.15-1) with vdr-plugin-vnsiserver (1:1.3.1) combined with vdr (2.2.0-5) and kodi (16.0+dfsg1-1). I tried briefly using the upstream plugins for both VDR and Kodi just to be sure I'd produce the same error, and got the same so I started by reporting this on the Kodi VDR backend forum. If I don't get a response there in a few weeks, I'll file it as a bug against kodi-pvr-vdr-vnsi instead.

For now, I gave up on VDR (which I rather liked, very old-school Unix-server module was to build a PVR), and tried MythTV instead since it's also GPL'd. Since there weren't Debian packages, I followed this building from source tutorial on MythTV's website.

I didn't think I'd actually need to install MythWeb at first, because I am using Kodi primarily and am only using MythTV backend to handle the tuner card. It was pretty odd that you can only configure MythTV via a QT program called mythtv-setup, but ok, I did that, and it was relatiavely straight forward. Once I did, playback was working reasonable using Kodi's MythTV plugin. (BTW, if you end up doing this, it's fine to test Kodi as its own in a window with a desktop environment running, but I had playback speed issues in that usage, but they went away fully when I switched to a simple .xinitrc that just called kodi-standalone.

The only problem left was that I noticed that I was not getting Event Information Table (EIT) data from the card to add to the Electronic Program Guide (EPG). Then I discovered that one must install MythWeb for the EIT data to make it through via the plugin for EPG in Kodi. Seems weird to me, but ok, I went to install MythWeb.

Oddly, this is where I had the most trouble, constantly receiving this error message:

PHP Fatal error: Call to a member function query_col() on null in /path/to/mythweb/modules/backend_log/init.php on line 15

The top net.search hit is likely to be this bug ticket which out points out that this is a horrible form of an error message to tell you the equivalent of “something is strange about the database configuration, but I'm not sure what”.

Indeed, I tried a litany of items which i found through lots of net.searching. Unfortunately I got a bit frantic, so I'm not sure which one solved my problem (I think it was actually quite obviously multiple ones :). I'm going to list them all here, in one place, so that future searchers for this problem will find all of them together:

• Make sure the PHP load_path is coming through properly and includes the MythTV backend directory, ala:

  setenv include_path "/path/to/mythtv/share/mythtv/bindings/php/"

• Make sure the mythtv user has a password set properly and is authorized in the database users table to have access from localhost, ::1, and 127.*, as it's sometimes unclear which way Apache might connect.
• In Debian testing, make sure PHP 7 is definitely not in use by MythWeb (I am guessing it is incompatible), and make sure the right PHP5 MySql modules are installed. The MythWeb installation instructions do say:

  apache2-mpm-prefork php5 php5-mysql libhttp-date-perl

  And at one point, I somehow got php5-mysql installed and libapache2-mod-php5 without having php5 installed, which I think may have caused a problem.
• Also, read

  this thread from the MythTV mailing list as it is the most comprehensive in discussing this error.

I did have to update the channel lineup with mythfilldatabase --dd-grab-all

Posted on Sunday 13 March 2016 at 12:50 by Bradley M. Kuhn.

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