I've been using VDR for a long time with one DVB-C card. Now I've added a second, identical card (Technotrend DVB-C 2.1).
I get a picture, but it's of very low quality and breaking up all the time. Do I have to do something special to get this setup to work properly? Suggestions?
VDR: 1.3.27 DVB: latest CVS
Here's the lspci output for the cards (formatted for readability):
0000:00:0b.0 Multimedia controller: Philips Semiconductors SAA7146 (rev 01) Subsystem: Technotrend Systemtechnik GmbH Technotrend/Hauppauge DVB card rev2.1 Flags: bus master, medium devsel, latency 64, IRQ 11 Memory at cfffce00 (32-bit, non-prefetchable)
0000:00:0d.0 Multimedia controller: Philips Semiconductors SAA7146 (rev 01) Subsystem: Technotrend Systemtechnik GmbH Technotrend/Hauppauge DVB card rev2.1 Flags: bus master, medium devsel, latency 64, IRQ 5 Memory at cfffcc00 (32-bit, non-prefetchable)
/Erik
erik@tjernlund.net(Erik Tjernlund) 25.06.05 13:00
I've been using VDR for a long time with one DVB-C card. Now I've added a second, identical card (Technotrend DVB-C 2.1).
I get a picture, but it's of very low quality and breaking up all the time.
How have you wired the 2 cards to your one cable cable? The direct cable signal is usually not able to drive 2 receivers.
Do you have error messages in /var/log/syslog?
Do I have to do something special to get this setup to work properly? Suggestions?
- Use the new card "in place" of the old to make sure that this new card is not DOA
- Place the new card (alone) into the intended slot.
- use different slots
- Use the old card as second board
- Remove all hardware not required
- Tell the BIOS to reassign the PCI resourses
VDR: 1.3.27 DVB: latest CVS
Here's the lspci output for the cards (formatted for readability):
0000:00:0b.0 Multimedia controller: Philips Semiconductors SAA7146 (rev 01) Subsystem: Technotrend Systemtechnik GmbH Technotrend/Hauppauge DVB card rev2.1 Flags: bus master, medium devsel, latency 64, IRQ 11 Memory at cfffce00 (32-bit, non-prefetchable)
0000:00:0d.0 Multimedia controller: Philips Semiconductors SAA7146 (rev 01) Subsystem: Technotrend Systemtechnik GmbH Technotrend/Hauppauge DVB card rev2.1 Flags: bus master, medium devsel, latency 64, IRQ 5 Memory at cfffcc00 (32-bit, non-prefetchable)
Are those interrupt shared?
/Erik
-- "Put me back on my bike!" -- Tom Simpson http://erik.tjernlund.net/ http://erik.tjernlund.net/pictures/
vdr mailing list vdr@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr
Rainer---<=====> Vertraulich // // <=====>--------------ocholl, Kiel, Germany ------------
On Sat, Jun 25, 2005 at 01:00:35PM +0200, Erik Tjernlund wrote:
I've been using VDR for a long time with one DVB-C card. Now I've added a second, identical card (Technotrend DVB-C 2.1).
I get a picture, but it's of very low quality and breaking up all the time. Do I have to do something special to get this setup to work properly? Suggestions?
This might sound insane, but please try it because it does work.
Try shining a torch on the DVB-C card - you should almost instantly see a boost in picture quality - it works for me... torch on card = watchable signal.. no torch = breakups, loads of UNCs...
I know people who have mounted lights inside their PC not for any decorative or ricer effect, but because it actually /does/ increase the efficiency of the frontend / tuner :)
Cheers, Gavin.
Gavin Hamill wrote:
On Sat, Jun 25, 2005 at 01:00:35PM +0200, Erik Tjernlund wrote:
I've been using VDR for a long time with one DVB-C card. Now I've added a second, identical card (Technotrend DVB-C 2.1).
I get a picture, but it's of very low quality and breaking up all the time. Do I have to do something special to get this setup to work properly? Suggestions?
This might sound insane, but please try it because it does work.
Try shining a torch on the DVB-C card - you should almost instantly see a boost in picture quality - it works for me... torch on card = watchable signal.. no torch = breakups, loads of UNCs...
I know people who have mounted lights inside their PC not for any decorative or ricer effect, but because it actually /does/ increase the efficiency of the frontend / tuner :)
How about hanging a dead chicken or two in front of tv or around the antenna :) You may need to experiment with the amount of feathers left on the bird or plucked off.
On Sat, Jun 25, 2005 at 06:31:33PM +0300, Lauri Tischler wrote:
How about hanging a dead chicken or two in front of tv or around the antenna :) You may need to experiment with the amount of feathers left on the bird or plucked off.
Bah :) I knew someone would reply with a smart answer like that :)
There is a sound scientific reason why shining light on the ICs has this effect - something so do with the chemical compounds used in manufacture..
Whatever the reason, it's a low-tech and cheap way of boosting a signal since you can't just plug a booster into a cable-TV feed :))
Cheers, Gavin.
Hmm. Ok. I've tried lots of different stuff now, but no change. Still unwatchable with two DVB-C cards in the machine. Tried to measure the signal strenght with the femon plugin, but I'm not really sure how to interpet that the signal-to-noise (SNR) ratio goes between ~87-91%.
If it is the signal strength, what do I do? Buy an amplifier? Use the shortest possible cable?
Rainer Zocholl wrote (2005-06-25 15:51):
How have you wired the 2 cards to your one cable cable? The direct cable signal is usually not able to drive 2 receivers.
I've just taken the coax cable from the cable-tv wall outlet, plugged in the first card and then used a short coax cable and connected the two cards.
Do you have error messages in /var/log/syslog?
No, no errors at all.
- Use the new card "in place" of the old to make sure that this
new card is not DOA
Check. Doesn't seem to be anything wrong with either card.
- Place the new card (alone) into the intended slot.
Check.
- use different slots
Check.
- Use the old card as second board
Check.
- Remove all hardware not required
Nothing in the machine except the two DVB cards and an AGP graphics card.
- Tell the BIOS to reassign the PCI resourses
Tried to fiddle with the PCI settings in the BIOS, but no change.
Are those interrupt shared?
Not sure. How can I check that?
/Erik
erik@tjernlund.net(Erik Tjernlund) 25.06.05 20:19
I've been using VDR for a long time with one DVB-C card. Now I've added a second, identical card (Technotrend DVB-C 2.1).
I get a picture,
Where do you get the picture? When connecting a TV on the second card or when recording and viewed via the first?
AFAIK VDR is supporting only one primary device.
but it's of very low quality and breaking up all the time.
Hmm. Ok. I've tried lots of different stuff now, but no change. Still unwatchable with two DVB-C cards in the machine. Tried to measure the signal strenght with the femon plugin, but I'm not really sure how to interpet that the signal-to-noise (SNR) ratio goes between ~87-91%.
that value should be OK. (I am running at STR resp. SNR as low as 65% with DVB-S)
If it is the signal strength, what do I do? Use the shortest possible cable? Buy an amplifier?
I've just taken the coax cable from the cable-tv wall outlet, plugged in the first card and then used a short coax cable and connected the two cards.
Have you swapped the the sequence: connect the wall outlet cable to the second card and then interconnect the first card to the second?
I looks very much that: The second card does not get enough signal(as i said: The cable signal is typically so low that not more than one receiver can be conneted), very annoying. So you need an amplifier.
Maybe an external splitter would be worth a test too, so both cards gets a lower level Maybe something like BVE 2-01 @ 2,90 Euro.
An amplifier like Axing TVS 10-00 37.90
might be too fat.
But don't by too cheap. The amplifier must be specified for "cable" else the signal quality may degrade.
But a
Axing TVS 8-01 16,90Euro TV distribution amplifier "suitable for CATV (TV, Radio)"
would be sufficient too. (See reichelt.de for a datasheet)
- Use the old card as second board
Check.
That means: If you use the old card as second card the receiptiton on the second card(=now old card) is still broken?
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First I want to thank you Rainer for all your help. It's very much appreciated.
I've been trying different things all weekend and I'm now pretty sure that my lossy picture problem is not related to the cable-tv signal strength at all. I think it is hardware related and specifically something with the PCI bus.
For example, if I change the PCI latency timer on the cards (setpci -s 00:90.0 LATENCY_TIMER=80), the picture becomes better on some channels (still not watchable though) and the thing these channels seem to have in common is their lower data rate.
Are there any other settings I can play with?
My next thing to try is to use another motherboard and see if it makes any difference. If it does, it's a bit annoying, as I really wanted to use the first machine.
Have to get it fixed in 4 days because it's when Tour de France begins. Allez Ullrich :-).
Rainer Zocholl wrote:
I looks very much that: The second card does not get enough signal(as i said: The cable signal is typically so low that not more than one receiver can be conneted), very annoying. So you need an amplifier.
/Erik
- -- "Put me back on my bike!" -- Tom Simpson http://erik.tjernlund.net/ http://erik.tjernlund.net/pictures/
-
Erik Tjernlund -
Gavin Hamill -
Lauri Tischler -
Rainer Zocholl