[linux-dvb] [DVB-T] lockingproblems

[Torsten Kunkel <dvbml@tkunkel.de>]

Hi,

I'm running vdr and have some huge problems with my system.
I use one dvb-s and one dvb-t in my computer (same situation with only 
the dvb-t inside).

When zapping in vdr from the dvb-s-channels to one of the dvb-t-channels 
vdr stands still for about 10sec then it shows a black screen, I have to 
do this several times (about 5-10) and then suddenly the channel appears.
From this moment on, I have on this channel a perfect image (femon 
shows values above 90% for signalstrengh and zero errors).
My homeregion is marked as "indoor aerial" but my dvb-t is plugged in my 
roof aerial, so this can't be a problem.
Mostly the problems continue, e.g. when switching from RTL to Sat.1 the 
same game comes on... once again black screen (no lock) and so on, until 
the channel appears.

Becaus of this I mustn't programm any timer for the dvb-t-channels, 
because it would just record a black screen.

I can reproduce the behavior without vdr:

b5:/usr/src/vdr/dvb-apps/util/szap # ./tzap -c ./de-Braunschweig "RTL 
Television"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
reading channels from file './de-Braunschweig'
tuning to 498000000 Hz
video pid 0x0151, audio pid 0x0152
status 00 | signal 9696 | snr 0000 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr b0b0 | ber 0001fffe | unc 00000000 |
status 00 | signal cccc | snr 0000 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr 6464 | ber 0001fffe | unc 00000000 |
status 0c | signal cdcd | snr 0000 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr 7c7c | ber 0001fffe | unc 00000000 |
status 0c | signal cdcd | snr 0000 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr 8383 | ber 0001fffe | unc 00000000 |
status 0c | signal cdcd | snr 0000 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr 8383 | ber 0001fffe | unc 00000000 |
status 0c | signal cdcd | snr 2424 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr 8f8f | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr b6b6 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr bbbb | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr b8b8 | ber 0001fffe | unc 00000000 |
[endless]

after ctrl-c

b5:/usr/src/vdr/dvb-apps/util/szap # cat /proc/interrupts  > 
/freigabe/int_nachher
b5:/usr/src/vdr/dvb-apps/util/szap # ./tzap -c ./de-Braunschweig "Sat.1"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
reading channels from file './de-Braunschweig'
tuning to 658000000 Hz
video pid 0x0181, audio pid 0x0182
status 00 | signal 9696 | snr 0000 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr e0e0 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr b4b4 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr b2b2 | ber 0001fffe | unc 00000000 |
status 00 | signal cccc | snr b3b3 | ber 0001fffe | unc 00000000 |
status 00 | signal cccc | snr bbbb | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr bebe | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr b0b0 | ber 0001fffe | unc 00000000 |
status 00 | signal cbcb | snr 5858 | ber 0001fffe | unc 00000000 |
status 1f | signal cccc | snr fefe | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK
status 1f | signal cccc | snr 0000 | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK
status 1f | signal cdcd | snr fefe | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK

after ctrl-c

b5:/usr/src/vdr/dvb-apps/util/szap # ./tzap -c ./de-Braunschweig "RTL 
Television"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
reading channels from file './de-Braunschweig'
tuning to 498000000 Hz
video pid 0x0151, audio pid 0x0152
status 00 | signal cdcd | snr 9191 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr 9191 | ber 0001fffe | unc 00000000 |
status 00 | signal cdcd | snr aeae | ber 0001fffe | unc 00000000 |
status 1f | signal cdcd | snr fefe | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK
status 1f | signal cdcd | snr fefe | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK
status 1f | signal cdcd | snr fefe | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK

Now it works "at once"


I had this problem since I bought my dvb-t-card, but the last month made 
it harder and harder to use the card.

I tried dvb-1.1.0, dvb-1.1.1 and currently dvb-cvs.

One final information.
I noticed it's impossible to get a lock in my dvb-t when the dvb-s has a 
recording (I tried to get a lock about 200 times on different channels 
to be shure). I hope this helps you.

For a newbie like me it looks like some kind of timing-problem, because 
sometimes it workes, othertimes it does not.
But you are the experts :)


If there is anything I could give to you in order to analyse or if there 
is any information you need, please contact me.

Hopefully
    Torsten