multiple instances of a direct show graph

NTDEV
1

Hi All,

How to support multiple instances of a direct show graph for Kernel
streaming drivers for a pin/stream.

We are developing a kernel streaming driver which has a analog video pin, I
want to know how to support multiple instances of directshow graph for that
pin. In the HW_STREAM_INFORMATION intially the value was 1, which I have
changed to 2 then I am able to get two directshow graphs for the pin one
more pin with same name gets added in the graph after I connect. Is this the
ecpected behaviour and the correct way of doing?

Is there any help available on this.

Any information is helpful.

Thanks and Regards,
Kdar.

2

> Is this the expected behaviour and the correct way of doing?
Yes this is the expected behaviour; I’m not sure about stream mpdrivers
but in the avstream model the similar manipulations with
KSPIN_DESCRIPTOR_EX.InstancesPossible / InstancesNecessary cause
DS Filter works like infinite pin tee filter (see example in DS SDK).
IMHO this counters have sense for splitter filters only and have no
relations
with number of running graphs (possibly in different processes).
So if you need two or more separate graphs to run simultaneously you need
to do something on device level. AFAIR avshws driver suggests to check
number of
working pin instances inside AVStrMiniSetDeviceState routine
(Acquire/ReleaseHardwareResources subroutines).

Hope this would help you.
Igor