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[linux-dvb] Re: Continuity Errors with tda10021 (Re: Distordedvideo with Cinergy1200 DVB-C)



Robert Schlabbach wrote:
From: "Anssi Hannula" <anssi.hannula@gmail.com>

I tested here (QAM128, Tampere Finland) using the exact same
tda10021-i2c-register values windows driver is using (AGCREF 0x50, LTHR
0x2d, MSETH 0x2d, PWMREF 0x80, checked with saa7146dump). It did not
affect the distortions. I think the problem isn't in those.

Is it possible that the "distortions" you are seeing are _not_ the result
of reception errors, but rather the result of incorrect DMA transfers from
the SAA7146A to the PCI bus? If you have no issues with QAM64 channels,
that might only be due to their lower data rate.
We have no QAM64 channels here, so I couldn't test.
Though I noticed that in Windows there is some activity in SAA7146 DMA3 control registers, when in Linux those are zeroed, but I don't know if this is at all related to this problem.

You should make sure the register bit which makes the TDA10021 set the TEI
bit in any packets incorrectly received, and then dump and examine the raw
MPEG-2 transport from from an QAM128 channel. If you have TEI errors and
continuity errors in there, it's a reception problem. However, if you
_only_ have continuity counter errors in there, it's a DMA error.
BER and UNC were zero, doesn't that mean that the tda10021 received them correctly?

If the error indicator bit is "MSB of the second byte", the tda10021 currently (as by default) sets the error bit in case of an error.
"IEI : when high, IEI inhibits setting the error indicator bit (MSB of the second byte) in the MPEG2 packet in the event of an uncorrectable RS block. The default value is IEI = 0."

How do I inspect the TS for continuity and/or TEI errors?

Unfortunately I can't do any new tests anymore, as the card was my friend's and he is using the 14 day product return right of remote selling we have here in Finland. I'm confident that others who have this problem can continue testing. I still have the TS and register dumps, though.

--
Anssi Hannula




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