[mythtv] Corrupt analog recordings

Tyson Harding tharding at cs.utah.edu
Mon Aug 14 15:59:35 UTC 2006

Torbjörn Jansson wrote:
> mythtv-dev-bounces at mythtv.org <> wrote:
>> Torbjörn Jansson wrote:
>>> For a few weeks now i've been having corrupt recordings from my
>>> analog card. This only happends for some of the recordings and i
>>> have not found any patern to it. 
>>> A corrupt recording have perfect audio but the video looks like a
>>> blocky mess, sometimes a more or less corrupted frame is visibel.
>> I saw the same thing start a few weeks ago. The problem I had was that
>> some change a few weeks ago has caused the analog video encoder to be
>> much less efficient. I noticed that when recording from the
>> analog card
>> the CPU utilization went to 100%, were before it used to only hit
>> 80%-85%.
> Hmm...
> Intresting, i'm prety sure i saw 100% cpu utilization too when one of the
> bad recordings was being recorded.
> My normal cpu utilization for analog recordins is also around 80-85% if i
> remeber correctly.
> Do you know what change it was that started this?
> And do you also have the message "v4l2: unable to handle these sampling
> parameters" in the backend log?

I think I found the problem...
rev 10580 fixes a bug where the iDCT and IME options were not actually 
being used. The patch attached to ticket 2061 
http://svn.mythtv.org/trac/ticket/2061 fixes this, causing significantly 
more CPU utilization. See if either of these settings are being used. If 
either are, then that is most likely the problem.

So this isn't actually a bug, but a bug fix ;)


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