[linux-dvb] Re: transport errors & femon

[Hamish Moffatt <hamish@cloud.net.au>]

On Tue, Feb 10, 2004 at 09:54:16AM +1100, Nigel Pearson wrote:
> >Then I tell Myth to change to station Y, which involves changing
> >frequency (and perhaps FEC rate & guard interval) as well as new pids.
> 
> 	I assume changing to something else from the same transponder
> (e.g. 9 Digital -> 9 HD -> 9 Guide) causes no problems?

Last night I saw it pretty badly with anything -> 2 SD. I didn't try
changing within a transponder; Myth doesn't seem to cope well with Nine
HD and I haven't added any of the other minor channels. I'll check
tonight.

> >After changing I get continuous transport errors and the picture/audio
> >breaks up. It doesn't seem to resolve within a few seconds. If I quit
> >live TV, Myth keeps the frontend running and tuned.
> 
> 	I would suspect Myth's buffering.

I would too. However, Myth is only declaring transport errors when it
sees the transport error bit in the MPEG-2 TS packet headers. So I think
buffer management in Myth must be causing overflows on the card, or
something like that. That might explain how tzap/femon report no
uncorrected errors yet I still get error-flagged packets.

> 	As a test, you could try mplayer or Xine on /dev/dvb/adapter0/dvr0
> and see if they also have transport errors.

I get a low error rate with that. I haven't seen any problem changing
channel like the Myth problem when testing with Xine.

Hamish
-- 
Hamish Moffatt VK3SB <hamish@debian.org> <hamish@cloud.net.au>


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