[mythtv-users] unencrypted QAM scanner and dynamic channel insertion

[Andrew Kuan]

I hacked together a script that scans my cable feed for unencrypted QAM
channels and then does the following:

   1. Creates a channels.conf file and plops it into the .mplayer config
   directory
      - 0:565778200:QAM_256:161:164:10
      - 1:619780900:QAM_256:113:116:7
      - 2:625781200:QAM_256:0:0:7
      2. Grabs a single frame as a jpeg and copies it to a folder on
   my web page for browsing
   3. Inserts new channel and dtv_multiplex records:
      - insert into dtv_multiplex
      (mplexid,sourceid,frequency,modulation,symbolrate,polarity,sistandard)
      values (91,5,619780900,'qam_256',0,'v','atsc')
      - insert into channel
      (chanid,channum,freqid,sourceid,callsign,name,mplexid,serviceid,atscsrcid)
      values (5901,901,901,5,'TMPCHANO1','TMPCHANO1',91,7,0)

I'm running into a few strange problems though.

First off, the records I insert can't quite be tuned by MythTV for some
reason. The OSD will say "LAm Partial Lock" when I tune to one of these
channels and I get nothing. I can't seem to find any documentation on how to
interpret what that means. Can someone point me to where some doco for the
DVB OSD resides or explain what I'm doing wrong on those inserts?

Second off, because of the above problem, I use mplayer as a backup. I can
fire up one of these channels like this: "mplayer dvb://1" and sometimes it
works just fine. But for some shows mplayer has a terrible time dealing with
the channel's sound/A52 encoding and dies every few minutes. I'm certain
this isn't a CPU issue but rather a sound decoder problem since it only ever
uses 5% CPU while it's displaying one of these shows and mplayer never barfs
when I use the "-nosound" setting.

I'd welcome any suggestions on how to fix either problem -- including using
some software other than MythTV or mplayer to view these channels. I'm also
happy to describe and share the script (the hack that it is) if anyone's
interested.

Thanks!

Andy
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