[mythtv] DVB3.5 - removed channels won't come back

Taylor Jacob rtjacob at earthlink.net
Mon Jan 10 12:51:23 EST 2005

I don't think I was clear enough last time as to why the ServiceVersion is kept
in dtv_multiplex.

The VersionNumber is only supposed to change when the payload changes.  Like I
said before these tend to change slowly not hourly.  I have seen most of them
remain the same in my market since I got my card working with the dvb patch

In dtv_multiplex there also is a date field that is used to force an update
after some window of time has gone by.. This should elimimate the issue of it
rolling all 32 versions before you happen to re-tune unless your carrier is
severly broken.

The Scaning class also will crawl all entries in the dtv_multiplex whenever the
Recorder is not actively using the card and re-validate the Service Tables (SDT
/ VCT) and pull new guide information, so you should be hitting each channel
every few hours anyway whenever your backend isn't doing anything.

So the only scenario I can think of where the Version would change all 32 times
between tunings would be if you had a backend so busy recording that it never
could tune to that multiplex and all 32 versions rolled by, and you also
couldn't be using that multiplex for any recording.

The second scenario would be if you left your backend turned off for weeks at a
time, but the updatedate field in dtv_multiplex would force an update, so this
one seems eliminated.

I would think the chances of the scenarios listed above happening are so small
that it is justified to keep the version number in the DB and not hit the DB so
much validating information that for the most part should remain static..


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