[mythtv-users] Mytv Unreliable

[Frosty]

Tim Sawyer wrote:
> Hi Folks,
>
> I have a combined front end / back end, nvidia graphics card, Athlon 64 X2 
> 4400, Nova T-500 dual DVB-T tuner card, 1Gb RAM.  Root filesystem on a 
> different disk to the recorded programmes.
>
> I was ready to junk mythtv this time last week and go back to using a normal 
> shop-bought digibox. The problems I was having were:
>
> - live TV jerky
> - recorded programs playback blurred in fast pans (particularly noticable on 
> programme credits)
> - unreliability in recording, some tuners just wouldn't record programmes, so 
> when I came to look at the list of recorded programmes, there would be some 
> where it couldn't find the file, and there would be no picture in mythweb.  
> Sometimes the back end process would fail for some reason and then next time 
> I looked at the recorded programmes list it would tell me that the back end 
> was not running.
>
> I have since upgraded to 0.21 which fixed the first two of these problems.  TV 
> quality is now excellent, both in live TV and playing back existing 
> recordings.
>
> However, I've just been bitten by the second problem.  Only one of today's 
> recordings has actually recorded - the rest, mythtv thinks they've been 
> recorded, but there is no file on disk.
>
> I have a strong signal, which is split between TV and myth box using a Y 
> connector.  Normal analogue TV in this configuration is snowy, but digital is 
> ok.  Signal strength reported in the OSD is 58-62% ish.  I have three virtual 
> tuners on each physical one.
>
> Just tried going to live TV, and it couldn't lock into the channel before the 
> timeout.  I rebooted the box, and it suddenly could lock in.  The box has 
> only been up since yesterday evening when I upgraded to 0.21 and then 
> rebooted.
>
> Am I going to have a script a nightly reboot (windows!?) or does anyone have a 
> clue where I should start looking?
>
> Thanks,
>
> Tim.
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>   
Hi,

The Nova-T 500 has a known issue of losing 'lock' on one or both of the 
tuners. I have put an extensive amount of time into rying to debug the 
issue and have gotten nowhere. There are people out there with no issues 
at all, and there are others like me and you that have this annoying 
problem. I have been unable to determine the differences between mine 
and a working setup to find the cause.

I am using Debian Lenny, with svn compiled 0.21-fixes MythTV using 
latest firmware and fresh svn compiled v4l-dvb, using kernel 2.6.22 
debian installer kernel as well as 2.6.22.9 and 2.6.24.4 self compiled 
(2.6.24 made the problem much more frequent).

It only seems to happen once every few hours so I wrote a short perl 
script to restart MythTV once an hour, only if it was not recording. It 
polls the backend to check if it is recording, then restarts, and checks 
again an hour later. You can find this at 
http://www.nooblet.org/blog/2008/mythtv-dvb-reloadpl/ It requires a 
little editing of variables at the start of the script and assumes the 
backend is running local so it can run the restart script.

I have since replaced the Nova-T 500 with 2x Nova-T (single tuner 
variety) and have since had absolutely no problems for over a week.

Many thanks to those of you that know me in the IRC channels, I would 
just like to make a short point that the IRC channel was an extremely 
great help in diagnosing many issues regarding MythTV and I now have a 
working MythTV setup with 0 issues that can only be down to their help.  
xris, Dagmar, directhex, Dustybin, iamlindoro, hnitsuj, kormoc and 
anyone else I failed to mention that helped, thankyou very very much.

You can follow this issue at these locations:

http://www.mail-archive.com/linux-dvb@linuxtv.org/msg29209.html
    - A very long and still active thread with many people debugging 
this issue. There are some attempted fixes but these have not fixes the 
problem for everyone.

http://www.gossamer-threads.com/lists/mythtv/users/306857#306857
    - This issue has been discussed on this mailing list in the past.

http://www.linuxtv.org/wiki/index.php/Hauppauge_WinTV-NOVA-T-500#Losing_one_tuner.3F
    - LinuxTV wiki states they are aware of the problem and suggest 
disabling USB autosuspend.

http://www.mail-archive.com/linux-dvb@linuxtv.org/
    - The LinuxTV mailing list is quite active and the Nova-T 500 is 
discussed quite often there


Yours,
Frosty