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

Markus Schulz msc at antzsystem.de
Tue Mar 8 20:59:14 CET 2005


Am Montag, 7. März 2005 22:18 schrieb Robert Schlabbach:
> From: "Markus Schulz" <msc at antzsystem.de>
>
> > The packets are lost in dvb_dmx_swfilter_packets cause of sync byte
> > (0x47) can't be found at next "Modulo 188" address and so the whole
> > packet (next 188 bytes) are skipped.
> > i've build some debug code to search from this position for sync
> > byte and in my case the missing sync byte was everytime one byte
> > behind original position and the packet from this position one byte
> > to small (after 187 bytes the next sync byte is found).
>
> I have since bought a Cinergy 1200 DVB-C and wrote a Windows driver
> for it and ran into the same thing. It appears to be a timing issue
> between the demodulator and the SAA7146A (rather than a PCI DMA
> issue): It looks as if sometimes the "SYNC" line goes high so early
> that the SAA7146A latches in the last (check) byte of the previous
> packet and subsequently is one byte off on every byte.
>
> Try this: Invert the polarity of the output clock with which the
> SAA7146A latches in the bytes from the demodulator by _not_ setting
> the POCLKP bit in the POLA1 register (change the third byte in the
> third line of the init array from 0xa1 to 0xa0). This seems to cure
> the issue in my Windows driver.
>
> Please let me know what your results are.

works perfectly, no ts-packet loss anymore.
big thanks.


-- 
Markus Schulz




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