[linux-dvb] Re: dvb-kernel TS continuity errors

[Manu Abraham <manu@kromtek.com>]

On Mon September 27 2004 12:19 am, segarral@free.fr wrote:
> Hi,
>
> I have maybe this kind of problem with a WinTV Nova-S budget card:
>
> When I'm recording a TS, some payloads (188 bytes) are forgotten.
>
> A consequence is, for example, when I'm listenning to the 'Radio FG'
> with mpg123, I can read the error message:
>    Illegal Audio-MPEG-Header
>
> (RadioFG: 12207MHz-V-27500-3/4- APID: 243)


I get an error like this,  with around 12 streams. I have been doing some 
digging around, without much results lately

libdvbpsi error (PSI decoder): TS discontinuity (received 10, expected 9)
libdvbpsi error (misc PSI): Bad CRC_32 (0xcdf6ce8e) !!!
libdvbpsi error (PSI decoder): PSI section too long
libdvbpsi error (PSI decoder): TS discontinuity (received 15, expected 14)
libdvbpsi error (misc PSI): Bad CRC_32 (0xd360758c) !!!


Manu

> I have the same problem with some other transponders (not so many).
>
> I check this: When I edit the recording file and have a look to the counter
> which is in the header of payload of 188 byes, I can see some jumps.
>
> Is this the same kind of problem? Am I the only one in this case?
> please, if you have a WinTV Nova-S, could you tell me if you can
> listen to 'Radio-FG' without any 'Illegal Audio-MPEG-Header' ?
>
> PS: I added some lines to dvbtraffic to see when I loss some payloads
> (188bytes). If someone is interesting...
>
> Thinks.
>
> Selon Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>:
> > Klaus Schmidinger wrote:
> > > I'm currently testing VDR under kernel 2.6 with the dvb-kernel
> > > driver (version from linuxtv.org CVS as of 2004-09-10).
> > >
> > > When I run 5 parallel recordings on the same transponder
> > > (RTL, RTL 2, Super RTL, VOX and RTL Shop) it works just fine on a full
> > > featured DVB card, while I get TS continuity errors when I
> > > do the same thing on a WinTV NOVA-S budget card.
> > >
> > > What makes this so strange is that normally it is said that
> > > a _budget_ card can deliver the full TS, while a full featured
> > > card is limited in what it can deliver. In this scenario it would
> > > appear that the FF card works better than a budget card.
> > >
> > > Could it be that there is a bug in the budget card driver
> > > that causes problems with multiple recordings from the same
> > > transponder (which means high data transfer rate)?
> > >
> > > Note that with two recordings on the budget card (RTL and RTL 2)
> > > I don't get these problems. The more recordings I run on the same
> > > budget card, the more TS continuity errors I get. On the FF card
> > > with 5 recordings I don't get a single continuity error. Needless
> > > to say that the recordings where the continuity errors happened are
> > > broken (video and audio artefacts), while those made with the FF card
> > > are perfectly fine.
> > >
> > > Also, during all these tests there were no buffer overflows in VDR,
> > > and also none in the driver (at least none that were reported by the
> > > read() call).
> > >
> > > One observation is that with 5 recordings the FF card typically returns
> > > some 30KB in one read(), while the budget card delivers around 4KB per
> > > read(). So with the budget card there are apparently a lot more read()
> > > calls. Don't know whether this constitues a problem, though.
> > >
> > > Any ideas what could be causing this?
> > >
> > > Klaus
> >
> > I just realized that the dvb-kernel driver apparently numbers the
> > devices differently than the old DVB driver did. With the old driver
> > I had the following device sequence
> >
> >   0  FF card
> >   1  budget card
> >   2  FF card
> >
> > while with dvb-kernel I have
> >
> >   0 FF card
> >   1 FF card
> >   2 budget card
> >
> > I became aware of this when I was wondering why my CAM was detected
> > at the "second" card, while it is physically attached to the "third"
> > card (as seen by the old driver).
> >
> > So what I wrote above is apparently wrong - the budget card does deliver
> > a flawless data stream, even with 5 parallel recordings. It's the FF card
> > that has the problems.
> >
> > Klaus
>
> --