[linux-dvb] How to access /dev/videoK from /dev/dvb/adapterN?

Manu Abraham abraham.manu at gmail.com
Sat Jun 17 09:26:58 CEST 2006

Ralph Metzler wrote:
> Klaus Schmidinger writes:
>  > An application that uses the LinuxDVB driver can access the
>  > DVB devices via /dev/dvb/adapterN/* (N = 0, 1, ...). However,
>  > when it wants to, for instance, capture the current image on
>  > a device (like VDR with its GRAB command), it needs to access
>  > /dev/videoK, where 'K' is a number that is not directly related
>  > to the 'N' mentioned above for the DVB device.
>  > 
>  > So VDR has to do some guessing on which /dev/videoK device might
>  > belong to the /dev/dvb/adapterN device. This is getting particularly
>  > problematic if there are also other /dev/video devices that have
>  > nothing to do with any DVB devices.
>  > 
>  > Is there a defined way in which an application can query a DVB
>  > device for its related /dev/video device?
> Currently not.
> Since upcoming cards with decoder and V4L interface for those will
> need it too, should we add a call for this? In the DVB video device?
> We might also need something like this for audio.

Like what we discussed earlier, what about making the nodes children to 
the adapter device, this will shoot at least 2 or 3 birds in one shot. 
ie a /dev/dvb/adapterX device, all are just child nodes of the adapter 

This would solve

(1) solve the issue with the demux for multistandard devices
(2) This current situation
(3) Calls that might belong to more than one device/belonging to the 
card etc


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