[mythtv-users] Quality of recordings degraded

Joel Anderson myth at jobless.ca
Wed Jul 7 17:47:27 EDT 2004

Bob Cottingham wrote:
> Joseph A. Caputo said:
>>On Wednesday 07 July 2004 10:43, John OKeefe wrote:
>>>I just got my MythTV setup working and it has been up and running for
>>>almost two days. The recordings have been great so far. Then this morning
>>>it recorded a show and the quality of the recordings has degraded. This
>>>also happens in LiveTV. Specifically I am getting some slight noise and
>>>some transparent blue vertical lines in the picture. I have watched the
>>>shows on the T.V. without the MythTV box and they look fine so I know it
>>>is not the signal from that Satellite receiver.
>>>I was looking at the recording profiles last night but I am pretty
>>>sure I did not change any settings. Could changing the recording profiles
>>>i.e. bit rate or recording type affect the recording/LiveTV like I
>>>mentioned above?
>>>Any thoughts on what is causing this?
>>>Is the box getting to hot and that is affecting the picture? Is that
>>>something that typically happens? I am not at home right now so I am 
>>>unable to check the box to see if it is hot or not.
>>>Here are my system specs:
>>>KnoppMyth R4V4
>>>P4 1.4 Ghz
>>>120GB Maxtor 7,200 RPM hard drive.
>>>512mb ram
>>>AC97 On board sound.
>>>Elite P4VXMS motherboard.
>>>Thank you for any help in advance!
>>Shut down your box, power off, and reboot.  (Note: you must cycle power,
>>not just warm reboot).
>>This is a known problem with ivtv-driven cards (PVR-x50, M-179).  Not
>>sure if it's the firmware or the driver.
> I get this once in a while with my PVR-250 as well.  It's a grounding problem from what I understand.  Simply disconnect the coax cable and then reconnect.  Instantly fixed.  While rebooting will work too, there's no need in my experience to go to such lengths.
> Bob C

I've seen speculation that this is a grounding problem, but I have yet 
to see any evidence of that.  I've checked that my stuff is all grounded 
properly, and I still have it happen occasionally.  There was discussion 
on the ivtv dev list of this being a driver issue, and someone posted 
recently that it has been fixed in current ivtv cvs.

Most people either reboot or use the test_ioctl command that Kyle posted 
earlier in this thread.  I also found that simply going into live tv and 
changing the channel is usually enough to fix it on my setup.


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