[vdr] Troubles when resuming from EPG scan

Tuomas Jormola tjormola at cc.hut.fi
Fri Oct 7 15:12:21 CEST 2005


My VDR system is having some annoying problems with EPG scanning. I'm  
not quite sure where to begin looking for solution so I thought to  
share my experiences with this list.

First, the system configuration. A regular Athlon64 PC running Ubuntu/ 
breezy (i386, not 64bit amd64). This is a one-card VDR box with a  
Technotrend DVB-C 2.1 FF card installed. I've tried with Ubuntu's  
2.6.10 and 2.6.12 kernels and self-compiled 2.6.14rc2 (there was some  
DVB driver updates since 2.6.12 so I thought to try a later kernel  
too). dvb-ttpci firmware is 261f. VDR version is 1.3.33 with  
dvbplayer5 patch by Reinhard Nissl, and enAIO 2.6 and dvbsubtitles  
0.3.8 patch compiled by Rolf Ahrenberg. These plugins are used:  
control, subtitles, osdteletext, xine, text2skin, lcdproc, femon. I'm  
using the Xine plugin with Xine player to display TV with a projector  
connected to computer's DVI port. The TV network is HTV in Helsinki,  
Finland. I've got an HTV Conax card connected to the DVB-C card.  
channels.conf contains about 135 TV, radio and data channels.

When the EPG scan kicks in, either automatically after the EPG scan  
timeout is reached or manually choosing scan in EPG setup or after  
issuing SCAN command via SVDRP connection, live TV picture goes off  
and vdr-xine displays a NO SIGNAL picture as expected. But sometimes,  
it looks like the scan never completes successfully. After about 2  
hours since the "info: Starting EPG scan" message in syslog EPG  
bugfix statistics for various channels might appear to the syslog  
(but not always, I'm using the EPG bugfix level 3). But the channel  
that was on before starting the EPG scan is never switched back on.  
In fact, VDR is unable to display picture and sound on any channel  
anymore, not even after restarting VDR. You have to unload the  
dvb_ttpci driver with rmmod and modprobe it again and then it works  
again. Now the funny thing is that EPG scanning sometimes sort of  
works. It takes about 7 minutes to complete and then the last channel  
viewed is switched on again. However, many times after completing the  
scan, picture has all kinds of disorders so you really can't watch it  
and sound is awful snap, crackle & pop. Example can be seen in [1].  
This is on all channels, all muxen. I sometimes get that also when  
normally changing channels, but that's pretty rare. Again, just  
restarting VDR doesn't fix these disorders, you have to reload the  
kernel driver in order to get working picture. The syslog is flooded  
with messages that can be seen in [2]. Femon reports very good signal  
quality all the time.

And then, sometimes the scan works just fine, the last channel is  
restored normally with a clear picture and sound after the scan  
completes. I've not been able to find any pattern between these three  
possible outcomes (all channels lost, bad picture while changing back  
to the last channel, works ok) of EPG scan. Except that automatic  
scan seems to always produce the all channels lost scenario, though  
it shouldn't make an sense (the actual scanning process, whether  
launched automatically or manually, is always the same, right?). But  
anyways, when you leave the VDR box on for the night and try to watch  
TV the next day, there's always the NO SIGNAL picture greeting you  
and no channels available until VDR is stopped, kernel driver  
reloaded and VDR started again. Any idea what might cause the bad  
picture after resuming from EPG scan (and occasionally, while  
normally changing channels)? And why tuning any channel after  
initiating an EPG scan sometimes doesn't work? Is anyone else using  
HTV (or other) network experiencing this?

[1] http://solitudo.net/vdr-bad-picture.jpg
[2] http://solitudo.net/vdr-syslog.txt


Tuomas Jormola <tjormola at cc.hut.fi>

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