Hi all,
This is my first message and I am new to Windows Driver development so
apologies if I say something silly, I tried to search for an answer but I can't
find anything.
I started studying Windows driver development and I wanted to so something to
implement a loopback audio driver.
What I am trying to do is having two application running, A and B, and have
them communicating via the loopback driver:
- the output of A speakers becomes the input of B mic- the output of B speakers
becomes the input of A mic
B runs all the time, A is on request, it opens and closes the channel
I downloaded the Windows Driver examples from
https://code.msdn.microsoft.com/windowsapps/Windows-Driver-Kit-WDK-81-cf35e953
And I modified the msvad - vadsimpl implementation to remove the logic that
writes to a file and add a circular buffer in CopyTo and CopyFrom.
I also simplified the topology to be as follow:
static PCCONNECTION_DESCRIPTOR MiniportConnections[] ={ // FromNode,
FromPin, ToNode, ToPin
{ PCFILTER_NODE, KSPIN_TOPO_WAVEOUT_SOURCE,
KSNODE_TOPO_WAVEOUT_VOLUME, 1 }, { KSNODE_TOPO_WAVEOUT_VOLUME, 0,
KSNODE_TOPO_WAVEOUT_MUTE, 1 }, {
KSNODE_TOPO_WAVEOUT_MUTE, 0,
KSNODE_TOPO_LINEOUT_VOLUME, 1 }, { KSNODE_TOPO_LINEOUT_VOLUME, 0,
PCFILTER_NODE, KSPIN_TOPO_LINEOUT_DEST },
{ PCFILTER_NODE, KSPIN_TOPO_MIC_SOURCE,
KSNODE_TOPO_MIC_VOLUME, 1 }, { KSNODE_TOPO_MIC_VOLUME, 0,
PCFILTER_NODE, KSPIN_TOPO_WAVEIN_DEST }};
Everything works really well except that after 2 or 3 days the application B
(the one that runs ll the time) stops receiving audio, putting some tracing in
CopyFrom I noticed that one of the drivers stops calling CopyFrom, it only
calls CopyTo, while the other one calls both.
If I close and restart B, everything starts working again. If I run the same
test using VB calble (http://vb-audio.pagesperso-orange.fr/Cable/) it works
without errors for several days so I am assuming that there is something in the
driver that I didn't implement properly and it triggers only at random time.
Has anyone ever seen something similar before? I am not sure where to start
looking at.
Thank you very much for the help!
Best Regards,Andrea
