Author Topic: Mythtv corruption when recording with 2 or more tuners.  (Read 1142 times)

OnTarget

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Mythtv corruption when recording with 2 or more tuners.
« on: October 11, 2010, 07:54:18 am »
Hello,

When recording (or viewing) 2 or more shows on different muliplexs all of the recordings will go green and pixelate. If you stop the additional recording straight away everything goes back to normal. If you leave the recordings going eventually the tuner card will crash with i2c_scan errors. At this point you need to turn off the core and turn it back on to have mythtv start to function again.

This only happens when the second (or third) tuner is used. If can record 2 shows on the same multiplex with one tuner fine. I have tested all tuners individually and they are fine. Following other posts about the i2c_scan errors it suggested that poor signal may have been the issue. I have excellent quality signal in the 50-60% strength range but I went out and bought a booster just in case. Now my signal is 70-80% but had no effect on my problem.

Mythbackend logs show no error. dmesg and /var/log/messages also show no error unless you let the problem proceed to a tuner crash. I don't know how to access mythfrontend's output in linuxmce.

My system details are below. Any help would be greatly appreciated. I have exhausted all the this forum and google have on the subject.


Core
AMD phenom x4
4GB DDR3
1x 80GB hdd (os)
1x 1TB pipeline hdd (data)
3x Winfast USB DTV GOLD tuners
2x Gigabit nic

MD
Asrock 330HT diskless

Software
Linuxmce 8.10 net install as per wiki. Latest updates.
VDPAU on MD

Crawtech

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Re: Mythtv corruption when recording with 2 or more tuners.
« Reply #1 on: October 11, 2010, 08:30:22 am »
Hi
I would say the problem is with you turner card or hardware

I have 8 tuners on my system and  have at least 4 in use all the time and all in use some of the time with no problems at all


 
« Last Edit: October 11, 2010, 08:36:27 am by ihas »

purps

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Re: Mythtv corruption when recording with 2 or more tuners.
« Reply #2 on: October 11, 2010, 10:35:13 am »
Is your booster a "1 in, 3 out" type? Are you using a proper roof antenna, or an indoor one?

Remember you can have the best signal strength in the world, but it doesn't matter if the signal quality is rubbish. Maybe try adjusting the gain on the booster (start low/off, and try increasing it in small increments, see if it makes any difference).

In the name of diagnosing the problem (I am not suggesting this as a permanent solution), maybe get an indoor aerial (assuming you are using a roof one) and hook it up to one of the tuners. Tune the channels and make sure it works OK. Hook up the roof antenna to another tuner (I would suggest leaving the third one out of it for now). Then try it out. If it works, they you'll know it's a booster/antenna-related problem.
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OnTarget

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Re: Mythtv corruption when recording with 2 or more tuners.
« Reply #3 on: October 11, 2010, 12:48:34 pm »
Thanks for the replies.

All the tuners have been tested individually and all happily record 2 shows on the same multiplex. So I know the tuners are fine.

As far as the booster goes. I know it not the problem as I only purchased it as a potential solution. So most of my testing has been done without it. Our signal quality here is excellent, to the point that analog TV is flawless across all channels and you never get pops or clicks in the sound with digital. For reference its a 1 in 4 out booster.


purps

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Re: Mythtv corruption when recording with 2 or more tuners.
« Reply #4 on: October 12, 2010, 10:18:54 am »
Can I just confirm that you are aware that there is a difference between signal strength and signal quality?

Does your booster have gain control?

I still think that testing the tuners separately, one with external antenna, one with indoor antenna, would be a good idea in trying to narrow the problem down.
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OnTarget

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Re: Mythtv corruption when recording with 2 or more tuners.
« Reply #5 on: October 12, 2010, 12:14:23 pm »
Hi,

Yes I am aware of the difference between signal strength and quality. I will be trying your test as soon as I can borrow an indoor antenna.

I am also testing a usb power issue tomorrow. Either way I will post my results.

Cheers.

purps

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Re: Mythtv corruption when recording with 2 or more tuners.
« Reply #6 on: October 12, 2010, 02:30:43 pm »
OK cool.

Another thing that occurred to me, is that the booster should be as close to the tuners as you can get it, so one long cable from the aerial to the booster, and then short stubby ones from the booster to the tuners.

Either way, might also be worth checking the integrity of the cables, make sure they are properly shielded and haven't come loose inside the connectors or anything.

Good luck!
1004 RC :: looking good :: upgraded 01/04/2013
my setup :: http://wiki.linuxmce.org/index.php/User:Purps