Transition from tv_grab_uk_rt to tv_grab_sd_json

Hi.

I have made the transition from tv_grab_uk_rt to tv_grab_sd_json, following
the instructions in the MythTV wiki and in earlier mails to this list.

I encountered a few problems which others making the transition might want
to be aware of:

* Programme timings were all one hour early.  I suspect this is because
I'm still on a very old MythTV version (0.24).  Although the XML had
"+0000" as the timezone, MythTV was taking the times as local time (BST).
I fixed this by adding 

    $dt->set_time_zone('local');

before the first strftime call in write_programme.  This might cause
problems around the time when the clocks go back, but I hope I will have
upgraded MythTV before then - I've been putting it off because I plan a
hardware upgrade at the same time.  (Since I'm on MythTV 0.24 I also put
back the $previously_shown{'start'} = $dt->strftime('%Y%m%d%H%M%S %z');
line that was changed to '%Y%m%d' in XMLTV 0.5.68.)

* The xmltvid value for ITV1 London (Carlton) in the wiki didn't match my
tv_grab_sd_json output.  The wiki has:

central.itv1.itv.co.uk     21832       # ITV 1 London (Carlton)

but my tv_grab_sd_json output has:

<channel id="17468">
    <display-name>ITV1 (London)</display-name>

The value 21832 doesn't appear in my tv_grab_sd_json.conf file (even with
a "!" to indicate an unwanted channel).  I chose the GBR-0001314-DEFAULT
lineup (the south-east Freeview choice with Anglian/Carlton rather than
the one with Anglian/Carlton/Meridian), so I suspect 21832 might be a
Meridian channel.

* Some of my test runs reported "Use of uninitialized value in sprintf" for
the line: $ch{'id'} = sprintf($channel_id_format, $channel->{'stationID'});
in write_channel. It didn't happen in last night's run from cron and things
seem to be working, so I have ignored it, but the developers might want to
look into it.

Regards,
Geoff Clare.

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