[mythtv-users] restoring some channels to get back EIT functionality

[Stephen Worthington]

On Sat, 31 Dec 2016 14:33:38 +0000, you wrote:

>I have a dvb-s2 setup. Annoyingly, I've always had several copies of most
>channels, as in: BBC One on channel 27340, BBC One on 27360, etc (I am
>making the numbers up), plus the other variations such as BBC One Wales,
>BBC One NI and so forth. This meant that while scheduling recordings each
>movie would appear a dozen times.
>
>A few days ago I decided to get rid of the seemingly redundant channels.
>First I backed up the database. Then I went into mythtv-setup, channel
>editor, and deleted all the BBC One variations except BBC One HD. Similarly
>for other channels.
>
>All seemed to work fine and a few shows were recorded since.
>
>Now however I have discovered that the guide data for BBC One HD and BBC
>Two HD is always empty. (Other BBC channels, such as BBC News HD, do show
>EIT guide data, and so do Channel 4 HD, ITV HD and so forth.) So maybe (go
>figure) one of the variants I deleted had the EIT data and I should try to
>get it back.
>
>Of course if I were simply to restore the database from just before nuking
>those channels, I would lose the metadata of the shows recorded in the past
>week, so that doesn't work.
>
>I see there is an option to do
>
>mythconverg_restore.pl --restore_xmlvids
>
>hopefully without clobbering the rest of the database about recording
>metadata, however
>a) it's unclear whether the xmlvids (whatever they are) are the things I am
>trying to restore
>b) this seems to work not from a general full backup (the one the wiki
>heavily encourages one to make) but from a backup created
>with --backup_xmltvids, so that won't work either.
>
>Another route might be to redo a channel scan. I am always wary of that, as
>another thing more likely to screw things up than to fix them, but anyway,
>let's live dangerously.
>
>From the channel editor I try channel scan, but the first screen I
>encounter, scan configuration, warns me of a "failure to open card" in scan
>type.
>
>I remember I had no end of trouble doing a scan in the first place since
>upgrading to Mythbuntu 16.04 and Myth 0.28, because it always failed to
>detect the adapter. But I eventually got it to work by running
>
>femon -H a0
>
>in a separate terminal and leaving it going before opening mythtv-setup.
>I tried the same trick here but no joy: still "failure to open card",
>meaning I can't run a channel scan.
>
>Have I got any other options left to restore EIT on those channels?

You always have the option of restoring your database backup on
another PC, or more usefully, on a virtual PC.  The virtual PC
probably only needs mysql installed, not a full MythTV setup.  Then
you can dump only the channel table using mysqldump, and just restore
the channel table only into the real database.  It is also possible to
restore the old channel table to a different table name (eg
channel_old), then compare the two tables using SQL commands to see
what the differences are and where you went wrong, and just copying
the specific rows you want back again from the channel_old table to
the channel table, then finally deleting the channel_old table.

Alternatively, if you have an editor that can handle text files as
large as the uncompressed SQL file inside your backup file, then you
can just edit the .sql file and copy out the part that restores the
channel table and use the "source" command from a mysql prompt to
restore the channel table.

As always, when fiddling with your database, do a full backup before
you start.

Let me know if you need more explicit help with trying these options.