[linux-dvb] Re: A/V disturbances while recording (was:Today's CVS driver)

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

"Marcus O.C. Metzler" wrote:
> 
> Klaus Schmidinger writes:
>  > I just made the following experiment:
>  >
>  > My third DVB card recorded the current ZDF programme, while the first card
>  > immediately replayed the recorded data. My tv set is able to do PIP
>  > (picture in picture), so I was able to view the live signal from the AV output
>  > of the third card as well as the replayed signal from the first card (with a few
>  > seconds delay).
>  >
>  > Much to my surprise the audio disturbances and video artifacts happened on the
>  > *LIVE* signal - the recording just repeated what it had received earlier.
>  >
>  > Another test with 3sat showed the same errors in the *LIVE* signal.
>  >
>  > I then recorded 3sat with my third card and also tuned to 3sat on my first
>  > card, thus having the live picture on both a card that is currently recording
>  > and one that is just showing the programme. As I already expected, the disturbances
>  > happened only on the card that was recording.
>  >
>  > I double checked this with the CVS driver version 2001-05-17, where during several
>  > minutes of testing I have observed only one such disturbance. So it would appear that
>  > this has become a lot worse between CVS driver versions 2001-05-17 and 2001-05-25.
>  >
>  > Whether or not such disturbances happen apparently depends on what kind of
>  > programme is currently broadcast. There are times when (even with the latest driver)
>  > I can't observe any errors for several minutes, and other times when they occur every
>  > few seconds. It would appear that 3sat is a good test candidate, and here especially
>  > the "nano" programme. But also the ZDF shows this behaviour.
>  >
>  > Can anybody else reproduce these effects?
>  >
>  > Can the driver developers think of anything that might cause this?
>  > I don't think that the *live* signal should be affected by the fact that
>  > the card is recording!?
>  >
>  > Am I doing something wrong here?
>  >
> 
> My guess would be that it has something to do with OSD since that is
> the only thing we are not really using.

When these errors occur there is no OSD activity at all.

> We had no problems here.

I only have this on certain channels (so far I've seen it on ZDF and 3sat).

Klaus
-- 
_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
_______________________________________________________________


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