[mythtv-users] Trying to understand the multiplex values

Harry Devine lifter89 at comcast.net
Tue Dec 18 02:56:36 UTC 2007


Hello everyone,

I've been having trouble getting my Myth box to tune all of the channels 
that is being provided by Comcast.  I just upgraded to the SVN build as 
of 11/19/07, and tonight I thought I'd go through the effort of 
re-scanning my channels to see if my luck has improved.  I have my 
system set to NTSC for TV Format, us-cable as my frequency table (in 
mythtv-setup), and when I scan my channels on QAM-256 using the Cable 
frequency table, I get alot of channels that are named UNKNOWN108#5, etc.

Now, taking that channel as an example, I'm trying to figure out what 
the relationship is between the information for that channel in the 
channel table and the dtv_multiplex table.  For this channel, I see the 
following (I'm only showing the relevant columns):
chanid   channum   freqid   sourceid       callsign                   
mplexid   serviceid
2112      108#5      108      1            UNKNOWN108#5   67            11

For the dtv_multiplex table, I see the following information:
mplexid   sourceid   frequency       modulation   sistandard
67            1            699000000    qam_256      atsc

How does all of this information tie together?  How can I use what I'm 
seeing here to determine what channels I have so I can rename them 
properly (i.e. Channel 231 is my local HD ABC channel).  I recall 
reading in some post a while back that the mplexid somehow ties this all 
together. I just can't seem to figure out what the missing link is here 
in my case.

Any ideas or "pearls of wisdom"?

Thanks,
Harry



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