WASAPI
More info
- Owner
- Microsoft
- Released
- 2007
- Type
- Audio API
Windows Audio Session API — the audio interface that arrived with Windows Vista and, for the first time, gave applications a low-level path to the sound card without a third-party driver.
Before Vista, audio was mixed in the kernel by kmixer, with delays that made Windows useless for music without ASIO. Vista moved the audio engine into user space and put WASAPI underneath everything else. In shared mode an application's audio is mixed with the system's and resampled to the device format. In exclusive mode one application takes the device outright, bypasses the mixer and can send bit-perfect PCM — at the cost of silencing everything else.
Windows 10 cut the shared-mode buffer to a few milliseconds, and plenty of players and DAWs offer WASAPI as the default. ASIO still rules the studio: vendors' own drivers remain faster and more dependable, and habit is a powerful thing.