Support for Virtual Surround Sink

[jaakkopasanen]

Add support for Pulseaudio's module virtual surround sink. The module was recently changed to support longer impulse responses and the author promised to add support for asymmetric HRIRs with two files. WAVEFORMATEXTENSIBLE header is required by the virtual surround sink.

https://www.reddit.com/r/headphones/comments/er5rv0/adapting_hesuvi_presets_for_use_with_pulseaudio/

[kode54]

libsndfile may be able to handle the speaker presence flags, but I’m not sure.

[kode54]

I have completed my stereo convolver thus far, but need to produce test material. I will throw something together quickly with C and direct byte copying to avoid any floating point rounding issues, and see what it does when given a stereo set. It may need adjustment to the normalizing function to account for having twice as many channels to normalize for.

[aqxa1]

Pipewire supports Hesuvi type IRs out of the box with a filter-chain config file as an alternative to Pulseaudio.

I've tested the impulcifer demo and it appears to work, albeit with a big cut to volume (I'm not sure if that's expected). Standard Hesuvi IRs work fine as well.

EDIT: Volume issue occurs with Hesuvi on Windows as well, so not related to Pipewire. Probably an issue on my end.