[linux-dvb] Re: Ideas Wanted: Grundig STB Works, Nova-T Doesn't

["Robert Schlabbach" <robert_s@gmx.net>]

From: "Martin Smith" <martin@spamcop.net>
> That's interesting. Is there any way to prove where the corruption is
> happening?
> I guess if it's between PCI and main memory then it's very difficult
> to do this.

No, it's quite simple: The demodulator will only output either correct
packets, or ones with the error bit set. If you end up with packets that
don't begin with the SYNC byte (0x47), you have data corruption. If you
find continuity count errors in the stream, although there were no
transport stream errors, there were packets lost during the data transfer
(buffer overruns).

If you have some kind of MPEG-2 transport stream analysis tool, try dumping
the output from the card into a file and analysing it for errors...

> My test system is an Intel PIII 1GHZ with an Intel PIIX4 chipset and
> 768MB of RAM. It's maybe getting a bit long in the tooth but it's been
> stable for a long time.

PIIX4 is an IDE controller, AFAIK. Is it maybe an i440BX chipset? That's
what I am using on my (Windows) test machine and it's working well. The
only problem I had was that I had to fine-tune the SAA7146A PCI bursts for
my budget DVB-Cable card, because I had packets lost if the burst length
was too high...

> The machine that will be the eventual home for the cards is my analogue
> MythTV box, an Athlon 1800XP with Via chipset. I was hoping not to have
> to touch this until I had the card working in the test box.

It might just as well be working flawlessly in that box ;)

> Thanks for the information,

You're welcome.

Regards,
--
Robert Schlabbach
e-mail: robert_s@gmx.net
Berlin, Germany



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