Wasapi Exclusive mode with Hardware Acceleration doesn't seem to work

Question

We have an application that uses Wasapi in event-driven exclusive mode, and it works fine on most devices. However, when we run across a machine that has enabled Hardware Acceleration for the playback device properties, we get silent output. No errors are reported, and the Wasapi system appears to function perfectly normally in debug. However the output is simply silent.

If we turn off hardware acceleration using the sound properties in control panel, it works just fine.

So far, we've been only able to do this on low-end devices using the Intel SST Audio Device (WDM).

Anyone else run into this? Is there a special WASAPI initialization procedure we have to do to work with hardware-accelerated devices in exclusive mode?

Answer 1

I have the same issue but according to microsoft https://msdn.microsoft.com/en-us/library/windows/hardware/dn302026(v=vs.85).aspx the offloaded streams go directly to the hardware bypassing the software sound engine. However, it also says that a loopback stream is returned to WASAPI through the loppback pin which is provided by the driver. I could not figure out how to access that stream though.