[mythtv-users] Mythtv can't tune one channel tunable using tzap+mplayer
w.munson at comcast.net
Fri Dec 28 22:28:25 UTC 2007
Ian Peake wrote:
> [Apologies if a similar message is posted later.. my first mail was
> from a not-subscribed
> alias address and has been held for moderation and/or dropped for several days.]
> I have ongoing problems with mythtv tuning just one particular multiplex
> ("SBS") which tunes passably using tzap+mplayer.
> Can someone suggest next steps to tracking down this problem?
> See backend log at http://pastebin.ca/828312 and further details below.
> The problem is quite reproducable on my setup:
> Mythfrontend OSD always gives "LMs" (partial SDT) with signal of approx 58% but
> no better, i.e.: no picture or sound. I can tune with tzap_mplayer.
> Mythtv is a recent Debian build 0.20.2.svn20071210-0.0 and several earlier
> I am using a Hauppauge Nova-T 500 with very recent
> v4l-dvb subsystem (from mercury repo sources),
> I have tried patching with the Hauppauge "reception patch"
> I have also enabled the low noise amplifier (force_lna_activation=1).
> Admittedly reception seems only marginal to fair
> (approx. 20m connection to old outdoor antenna),
> however I can adequately tune all channels apart from SBS
> in mythtv. (That is, about four other multiplexes over a combination of HD/SD.)
> I can also tune all channels using an STB on the same antenna.
> Moreover, tzap+mplayer works for all multiplexes/channels,
> and seemingly on both tuners.
> The one odd thing is that tzap reports a SNR of 0. I have seen
> that reported elsewhere for the Nova-T 500 but not any
> solution or explanation.
> Admittedly signal quality (BER metric) seems quite variable
> rapidly while using tzap.
> A similar problem described at
> was solved by manually adding 166667 to the frequency of the
> multiplex. That doesn't seem to work for me.
> It wouldn't surprise me if I somehow corrupted mythconverg tables
> but as far as I can interpret the diagnostics and log
> myth is at least getting a lock.
> tzap "SBS" shows..
> using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
> tuning to 536625000 Hz
> video pid 0x00a1, audio pid 0x0051
> status 07 | signal 9748 | snr 0000 | ber 001fffff | unc 00000035 |
> status 1f | signal 978f | snr 0000 | ber 00000000 | unc 000000d8 | FE_HAS_LOCK
> status 1f | signal 97c8 | snr 0000 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 1f | signal 9765 | snr 0000 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
From your tzap report I would say that you may need to add a new
transport to your dtv_channel table with a freq of 536625000 Hz and then
set the channels table entry for your problem channel to your new
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