[pvrusb2] HVR 1900: using analogue and DVB simultaneously?

[roccomoretti]

Mike Isely wrote:
> On Mon, 30 Mar 2009, Martin Dauskardt wrote:
> 
>> Now that the HVR 1900 is available in Germany I think about buying it.
>> Is it possible to use analogue and DVB-T simultaneously? If not, how do I 
>> switch? Is there a need to close the video device before I can stream from 
>> the DVB dvr device? 
> 
> Yes you are correct in that only one side (V4L vs DVB) can be open at a 
> time.  Opening the DVB side causes a mode switch to digital, while 
> opening the V4L side causes a similar mode swith to analog.

Regarding "closing" the video device, the answer is simple but not 
straightforward. ;)

The pvrusb2 driver takes care of mode switching automatically - you 
don't need to send any signals to the device to explicitly "close" one 
capture side before switching to the other. However, the driver won't 
let you perform the switch if there is any program which is still using 
the device. Where this becomes tricky is with programs like MythTV, 
which may have background processes which hold open the device while 
scanning for metadata. You need to turn these off before you can freely 
switch back and forth.