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Pinnacle PCTV40i analogue noise with recent kernel versions



Hi, Karsten

Karsten Suehring wrote:
Not sure whether we already had this:
Please ensure that you are using the new drivers from linuxtv.org.
The code supporting your version of the tuner is quite new and using
the old version causes an i2c failure. The only way out of this is to
power cycle the machine. This also means that you *must* ensure that
the system does not load old modules in between.


Okay, but that makes remote debuggig impossible :-(

Yes, but only as long as the silicon tuner versions are mixed up. So
-at least for analog, the problem vanisches after the driver update.

Not sure what you mean. To my experience, you should  *not* merge the
mercurial tre into the kernel source. just unpack it and do a make and
- optionally - a make install.


In the debian packages the modules direcory did not contain the links to
the original source build directory which are needed for the v4l build.
Took me some time to figure out why "make" in the v4l directory failed...

Aha, i see.

Aha. You mean the small dots? This is "cross luma" distortion. It occurs
when the decoder expects s-video but receives CVBS at the Y input. This
also occurs with not properly shielded s-video cables due to cross talk.
This is more common than you might expect.

If you are interested in the technical background:
The small dots in the coloured areas are the modulated colour carrier. At
PAL, this is a quadrature modulated 4.43MHZ carrier. In CVBS mode, a notch
filter suppresses this at the cost of some bandwidth. This filter is off
in S-video mode since there are separate inputs for the Y and C signals.


Well, the card is only equipped with a S-Video connector to the outside.
 I think a saw only a pin for connecting composite directly to the
board. I'm using the adaptor included in the package for connecting my
composite signal to the S-Video port. I'm not sure about the exact
specification of that adaptor.

Do I understand you right that the filter can be enabled on the card and
would probably solve my problem?

Thats possible. We should add an additional composite input with .vmux=0.
This makes the Y input a CVBS input and should solve your problem.
Can you please try it?

Hartmut

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