[linux-dvb] Re: cinergyT2: which kernel/usb module to use?

[Holger Waechtler <holger@qanu.de>]

Klaus Schmidinger wrote:

> Holger Waechtler wrote:
>
> > Klaus Schmidinger wrote:
> >
> > > John Dalgliesh wrote:
> > >
> > > > On Mon, 29 Nov 2004, Klaus Schmidinger wrote:
> > > >
> > > > > From an application programmer's view it really would be great if 
> > > > > the driver
> > > > > gurus could agree on a reference implementation of how exactly tuning
> > > > > and waiting for a lock is supposed to be done...
> > > >
> > > >
> > > >
> > > >
> > > > I must be missing something here, but where is it useful to wait 
> > > > for lock
> > > > anyway - what's wrong with just waiting for some data to come 
> > > > through? I'm
> > > > not having much luck imagining an application where the demod's 
> > > > internal
> > > > idea of lock is any use waiting for, over just waiting for the actual
> > > > data that you want to get out to arrive.
> > >
> > >
> > >
> > > Well, that's what VDR originally did.
> > > But then there was this never ending series of problems with "unknown
> > > picture types" and "video data stream broken", and the general 
> > > belief was
> > > that filters should only be set when a device has a stable lock.
> >
> >
> >
> > Where do these messages come from? A properly designed MPEG decoder 
> > should be able to handle any input and recover sync if the incoming 
> > data contains garbled packets (despite the fact that all demods but 
> > the stv0299A mut the TS if it is not valid). All decoders but the 
> > av711x do so (you get the idea why I call it ancient and broken then 
> > and when? - ;)
>
> Well, they may "ancient" and "broken", but AFAIK they're the only ones
> available. I'd gladly buy a better full featured DVB-S card (preferably
> HDTV replay capable), but to my knowledge there are none.

:) stop dreaming, hook in a software decoder. It's unlikely that such 
cards will ever get designed again, the main reason for computer 
equipment developers to do so is that Microsoft requires decoderless 
cards in their "designed for Windows" BDA requirements. The second most 
important one is the all-dominant cost argument: a decent MPEG-decoder 
processor costs almost as much as the entire cinergyT2 device bill of 
material. You probably get the idea why av711x-based cards still cost 
more than twice as much in the shops if normal sold (and the av711x is 
really not a "today's processor").

You'll be surprised about quality, performance and flexibility if the 
implementation is well-done -- VDR will be able to transparently play, 
encode, decode and transcode all video formats of your codec library 
including HDTV formats, MPEG4 and the DivX flavors.

> > I any case the frontend_notifier callback code in dvb_frontend.c 
> > should work around this av711x/stv0299A bug, doesn't it works 
> > anymore, did any of the recent changes introduced a bug in this code?
>
> The problem is that the dvb-kernel driver just doesn't run reliably 
> (at least
> for me). I recently tried the linux_2_4 branch, but every now and then a
> channel switch failed. So if these "recent changes" are not in the (old)
> DVB driver, I won't benefit from them.

Ermmm... isn't the linux_2_4 branch exactly the 1.1.x release source? 
You are really encountering new problems there?
With "recent changes" I meant Andrew's refactored code (now in the HEAD 
branch but not in linux_2_4).

Holger