[linux-dvb] Best way for multiple frontends on one dvb-adapter

Patrick Boettcher patrick.boettcher at desy.de
Thu Nov 3 09:47:45 CET 2005

Hi list,

I'm working on support for handling multiple frontends and their data 
inputs on DVB-USB devices. Therefore I had to change the dvb-usb-framework 
in order to register additional dvb-device-nodes and to handle an usb 
device with several input streams. If everything works out well, I can 
release this change just before those devices hit the market.

I know that some of the following issues have been discussed recently, but 
I'm not sure on which way we agreed on :).

The device has 2 (independent) DVB-T frontends connected to one 
USB-device-controller handling their (partial) MPEG2-TS data inputs. 
Demuxing has to be done in software.

For me as a newbie to multiple-input-cards it seems to be the "correct 
way" to register 2 frontends and 2 demuxs for one dvb-adapter.

This is how it currently looks like:

$ ls /dev/dvb/adapter0/
demux0  demux1  dvr0  dvr1  frontend0  frontend1  net0  net1

It is working well with tzap and mplayer (playing dvr0 and dvr1) under the 
assumption that dvr0 is connected to frontend0 and dvr1 to frontend1.

As Ralph pointed out, there are applications out there, which are not 
working with dvrX and demuxX (X >= 1). So in that case it's maybe better 
to register a dvb_adapter per stream-input to be more compatible with 

OTOH and IMHO, it would be better to extend the applications to make use 
of all the features of the DVB-API.

In the latter case the question remains, whether the assumption that all 
dvb/*0-nodes and all dvb/*1-node descibe one input stream good enough or 
not. Afaik it's not a good assumption. I hope I'm wrong. :)

What is "the correct way" to mount all *0 and all *1 logically together?

thanks for your help in advance,

   Mail: patrick.boettcher at desy.de
   WWW:  http://www.wi-bw.tfh-wildau.de/~pboettch/

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