[linux-dvb] Re: C/A routing Question

[Rob.McConnell@Zarlink.Com]

Thanks Johannes,

I agree that as more hardware with PVR capability is becoming available, we
will have to consider different routing scenarios.  The h/w that I am
working on allows for parallel/serial TSs from multiple sources as well as
from C/Is and from a HDD.  Yes, in the HDD case the complete TS that was
recorded on the HDD can be routed through the C/I.  This allows the TS to
still be recorded encrypted on the HDD and then decrypted through the C/I
(keys would have to be stored to prevent them expiring, etc.).

I would favour an IOCTL to setup the possible TS sources to the demux and
then the PID filters should have the choice of which TS source to filter
on.   For example, if the demux can only handle 2 TS inputs but there are 5
possible sources, then we need to setup a "router/switch" to implement this
and each PID filter would have to choose which TS input (#1 or #2).

Any more thoughts out there?

Best Regards,

Rob ;-)



                                                                                                                                
                      Johannes                                                                                                  
                      Stezenbach               To:       Rob.McConnell@zarlink.com                                              
                      <js@convergence.d        cc:       linux-dvb@linuxtv.org                                                  
                      e>                       Subject:  [linux-dvb] Re: C/A routing Question                                   
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                      linuxtv.org                                                                                               
                                                                                                                                
                                                                                                                                
                      24-Feb-2003 01:17                                                                                         
                      PM                                                                                                        
                                                                                                                                
                                                                                                                                




Rob.McConnell@Zarlink.Com wrote:
>
> I've looked at the Demux API and had a quick look at the C/A but I don't
> see an apparent way in which to route a TS from a different source other
> that from the front-end to a C/A device.  What I want to be able to do is
> route a TS from different front-ends and also a HDD to the C/A and then
> back in to the Demux.  This would require a router on the input side to
the
> C/A.
>
> Do we currently support this? If not, then would it make sense to put
this
> routing in the C/A device or the Demux?

Well, the demux API certainly has a weak spot here. We've been
discussing this off-list, but it's not yet clear how to clean
it up without breaking all applications _again_.

The Metzlers introduced DMX_SET_SOURCE, but it has no well-defined
semantics yet, and is even unimplemented for current drivers.

IMHO it is supposed to switch the input of the whole demux from
frontend to dvr device. (This somehow makes the input field of
struct dmx_pes_filter_params redundant.)
The stream you feed to the dvr device is then routed through the CA
device which is implicitely connected to the demux.
(Hardware: ECDs are usually embedded inthe demux, so you aren't free to
route
streams through them at will. CIs are usually connected between frontend
and demux, so you usually cannot pass a stream from the HDD through CI.
Or am I wrong?)

We talked to some Toshiba guys recently, and they would prefer
to have stream routing generally be done at the sink, i.e.
drop the DMX_OUT_DECODER thing and add VIDEO_SET_SOURCE,
AUDIO_SET_SOURCE etc.

I feel there's a need for a broader discussion here.


Best Regards,
Johannes


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