Hi, NetBSD-8 features and in-kernel audio mixer with a sun audio/OSS compatible audio interface.
Each instance of an open audio device provides a seperate audio device to each audio application/audio server with independent software volume for each channel. This makes it possible to run portaudio, SDL audio apps, pulseaudio, esd, nas, sun audio applications and OSS v4 applications, etc side by side. As for OSSv4 see: http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=46611 I imported the necessary ioctls into libossaudio for compatibility with oss v4 in 2014. The exported oss version number is still lower than v4 as the mixer control api is yet to be added. It makes it possible to use applications in package source that require oss v4 support and these addition of an oss v4 compatible api has been essential for many packages for quite some time. As for midi, These devices should be supported by midi(4). There are usb/spkr(4) attachments as well as midi ports found on older sound cards. Additionally there is also the pseudo audio device pad(4) which allows audio to be captured to file or used in conjuction with the bluetooth a2dp streaming daemon. I hope this helps, Best regards, Nat