Compatibility with foobar2000+foo_out_asio+WASAPI

[yzwduck]

FlexASIO doesn't work with foobar2000 with ASIO output and WASAPI backend (on my PCs).
FlexASIO initializes successfully, but hangs after entering stream callback. I can reproduce this issue on two different PCs.

I tested with FlexASIOTest.exe and it didn't report any error.

I also tested with foobar2000+asio using default (DirectSound) backend and it worked perfectly.

Log: FlexASIO.foobar+wasapi.log

foobar2000 1.4.8 https://foobar2000.org/
with plugin foo_out_asio 2.1.2 https://www.foobar2000.org/components/view/foo_out_asio

Steps to reproduce:

1. Get foobar2000 and the asio output plugin mentioned above,
2. foobar2000 File -> Preferences -> Playback -> Output, set Device to "ASIO: FlexASIO",
3. Play any audio file.

[dechamps]

Thanks for the report. I am indeed able to reproduce the exact same problem in the configuration that you describe.

My best initial guess as to what might be happening is that, when using WASAPI, the first stream callback fires in the context of the ASIOStart() call, and FlexASIO ends up blocking on that callback to complete before returning from ASIOStart(). It might be that foo_out_asio is doing the exact opposite (i.e. it waits for ASIOStart() to complete before returning from the callback), resulting in a deadlock.

The reason why other backends would work fine is because the interaction between ASIOStart() and the first stream callback depends on the backend used. For example with DirectSound the first stream callback fires after ASIOStart() returns.

When I have some time to work on FlexASIO I will dig deeper into the issue and hopefully come up with a fix.

[dechamps]

This is fixed in FlexASIO 1.6.