WASAPI driver type support

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mschoeffler
mschoeffler's picture
Joined: December 29, 2011

Hi Ross,
it seems that Windows Multimedia driver type is currently not using the Windows Audio Session API.
I'm just interested if you have any future plans in supporting also WASAPI as driver type?

Ross B.
Ross B.'s picture
Joined: April 11, 2009

Hi. "Windows Multimedia" is the standard WMME driver type that has been supported since Windows 95. It is the default because it is universally available. WASAPI was introduced in Windows Vista. It has a number of known bugs in different versions of Windows (notably some versions of Vista). These facts are my justifications for the current state of things.

> I'm just interested if you have any future plans in supporting also WASAPI as driver type?

As for the future. Yes. There are plans to support WASAPI and WDM/KS/WaveRT. Quite possibly in the near future -- the main issue will be broad testing to ensure stability -- possibly I could include these as "Experimental" driver types until they can be trusted in AudioMulch.

mschoeffler
mschoeffler's picture
Joined: December 29, 2011

Thank you for your quick reply!
It is good news that you have plans for WASAPI :)

Ross B.
Ross B.'s picture
Joined: April 11, 2009

I'd be interested to know why you think WASAPI is interesting for you. I've worked with all the APIs to some extent and in my view ASIO and WDM-KS are really the only two that are useful for pro-quality low latency audio [edit: on Windows]. Have you had a positive experience with WASAPI?

mschoeffler
mschoeffler's picture
Joined: December 29, 2011

At my place of work, we often use ASIO for newly developed applications that rely on low latency. Users, which have low-budget sound cards without ASIO support, have to install some "workaround drivers" (e. g. ASIO4ALL). In order to save this step for those users, i have started to evaluate WASAPI (especially the exclusive mode). My impression is that not that much audio applications support WASAPI. So I asked you, if there exist any plans for AudioMulch.

I've developed one application that uses WASAPI. The exclusive mode works well and I haven't had any mentionable problems. But it should be also mentioned that i have not that many users :)

Ross B.
Ross B.'s picture
Joined: April 11, 2009

The sound-driver in AudioMulch is done with portaudio (portaudio.com) -- it's an open source project that I was involved with originating a while back. There is a WASAPI version of PortAudio, and it is used by some apps -- so we have some experience with it. There seems to be many pitfalls, with different performance characteristics and bugs in Microsoft's implementation on different platforms. I think with Windows 7 it is more stable than on Vista for example. I think it is not so widely used because it was not very reliable in the early versions.

Overall, for AudioMulch, I would recommend that people who are serious about doing live audio processing get at least a music-oriented soundcard, they usually come with ASIO drivers anyway. That said, I often run ASIO4ALL on my laptop for basic testing.

paradiddle
paradiddle's picture
Joined: June 24, 2009

Native instruments do support wasapi but it's kind of useless as far as performance and latency. It's better to use asio4all if no asio cards are present. I don't have one on my laptop and I can set asio4all's buffer to 64 samples with no problem.