[linux-dvb] Re: Which CRC-code is used in TS of DVB?

[Holger Waechtler <holger@convergence.de>]

Rene Bartsch wrote:
> As subject says, which CRC-code is used in TS of DVB?
>
> I think I've read CRC32 somewhere - is that correct?
> it's CRC32, the decoder model is described in ITU-T H.222.0, Annex A.
it's used for section data only, read ITU-T H.222.0 for details.

> > > Nevertheless: 
> > > http://www.linuxtv.org/mailinglists/linux-dvb/2002/11-2002/msg00176.html is 
> > > interesting, from Oct Nov 2002 where Holger speaks about CRC32 checking 
> > > being broken in the av7110 firmware. Is this still the case and would that 
> > It is not broken, just not implemented.
>
> There have been mails on the List from Holger Waechtler that it has been
> reenabled - this was in October 2002. There also where mails on the
> kernel-ML about impementing a generic CRC32 class into DVB-kernel.
no, there is now a fallback in the software demux, you can use this by 
loading the driver with hw_sections=0. In this case you pass the data 
through the software demux where the crc32 checksum is correctly checked.

> OK, what passes the CRC-check, then?
When you enable DMX_CHECK_CRC only section data with valid CRC will 
arrive in userspace.

> > Yup, it is part of the demodulator hardware. 
> With the full-featured cards only or also with low-budgets?
yes.

Holger



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