[mythtv-users] abc and fox

Paul Bender pebender at san.rr.com
Sun Jul 6 16:51:13 UTC 2008


Shawn Hamzee wrote:
> Thanks Paul. Your answer makes sense. I'll go ahead and see what I can 
> do to delete those channels numbers and have myth try to tune in to them 
> again.
> 
> */Paul Bender <pebender at san.rr.com>/* wrote:
> 
>      > Shawn Hamzee wrote:
>      >> these are hd channels i am missing. they were on the same multiplex
>      >> of channel 110 on my cable providers coax. sorry for the lack of
>     info
>      >> in my first post. i'd like to know if this is me or a bigger problem
>      >> though. thanks.
> 
>     Off and on, I have a problem where my cable provider does not include
>     the ATSC channel number for the channel. The channel is there, but
>     MythTV could not tune to it because there was no valid ATSC channel
>     number included. Once I deleted the ATSC channel number from the MythTV
>     database, MythTV tuned based on the PID and everything was fine.

Here is an email that I sent to friends when I encountered the problem 
the first time. It includes some SQL commands that fixed the problem for 
me. Hopefully, it will make the process easier.

-----

I already posted some of this over at <http://hdtv.forsandiego.com>. 
However, I thought that I would mail it directly and include additional 
information.

I did some experimenting using my HDHomeRun and the hdhomerun_config 
utility for Linux.

When I scan, the correct serivice ids (i.e. 1706 and 1707) show up on 
channel 91 but without the ATSC channel numbers (i.e., without 6.1 and 
39.1). However, when I tune to the service id (aka PID or program 
number) and capture the stream, I can view the captured audio and video 
and it is correct.

Therefore, they appear to be missing some key information that most 
hardware / software use to determine that they have locked onto the 
stream. Apparently, the cable boxes that still work do not use this 
information.

For MythTV, the missing information is the ATSC channel number. Looking 
at the MythTV code for controlling the HDHomeRun device (isn't open 
source wonderful), I found that the ATSC channel number is used to tune. 
Only when the ATSC channel number is not present in the database does 
MythTV use the service id.

The solution is obvious: null the ATSC channel number for the crippled 
FOX and NBC channels. To view the relevant channel information, you can 
use something like:

SELECT atsc_major_chan,atsc_minor_chan,serviceid \
   FROM channel,videosource \
   WHERE videosource.sourceid=channel.sourceid \
     AND channum=706 \
     AND channel.sourceid=2' ;

Of course, replace the values of channum and channel.sourceid with the 
values for your setup and repeat for both FOX and NBC. My digital TV 
source from zap2it is source 2 in MythTV and I numbered my channels to 
match the TWC channel numbers.

To null the ATSC channel number, you can used something like:

UPDATE channel,videosource \
   SET atsc_major_chan=NULL \
   WHERE videosource.sourceid=channel.sourceid \
     AND channum=706 AND
     AND channel.sourceid=2 ;
UPDATE channel,videosource \
   SET atsc_minor_chan=NULL \
   WHERE videosource.sourceid=channel.sourceid \
     AND channum=706 AND
     AND channel.sourceid=2 ;

Again, replace the values of channum and channel.sourceid with the 
values for your setup and repeat for both FOX and NBC.

Once I did this, MythTV was able to tune FOX and NBC again.


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