sndio is the software layer of the OpenBSD operating system that manages sound cards and MIDI ports. It provides an optional sound server and a documented application programming interface to access either the server or the audio and MIDI hardware in a uniform way.[1] sndio is designed to work for desktop applications, but pays special attention to synchronization mechanisms and reliability required by music applications.[2]
The sndiod audio and MIDI server is the main component of sndio. It aims to fill the gap between programs requirements and the bare hardware as exposed by operating system device drivers.[3] This includes:[4]
perform re-sampling and format conversions; for instance to allow a program that requires 44.1 kHz sample frequency to use a device that supports 48 kHz only.
mix and route the sound of multiple programs; this allows multiple programs to use the audio device concurrently.
split an audio device into sub-devices, for instance allowing one program to use the front speakers and another program to use the rear speakers as they were independent simple stereo devices.
allow one program to record what other programs play.
control the volume.
route audio and MIDI data through the network; this allows programs running on one computer to use the sound card of another computer.
route MIDI data between programs, allowing one program to send MIDI data to another program as it was a hardware MIDI port. For instance for a MIDI sequencer to control a soft synthesizer.
start, stop and relocate synchronously a group of audio programs allowing multiple small programs to work together. This can be controlled through standard MIDI Machine Control (MMC) protocol, for instance from within a MIDI sequencer.
expose the sound card clock as MIDI timecode (MTC), allowing MIDI programs (e.g. sequencers) or MIDI hardware to be synchronized to audio streams.
The last few points are hooks in the sound server aiming to improve interoperability between audio and MIDI programs.[5] The use of standard MIDI protocols for volume and synchronization control enables interoperability with MIDI software or hardware connected to a computer.[6]
Historyedit
Minimal server capabilities were added to aucat—an audio stream manipulation tool and predecessor to sndiod—in October 2008,[7] shipping with OpenBSD 4.5.[8][9] In December 2011, aucat was renamed to sndiod[10] and later shipped with OpenBSD 5.1 as the default sound server started at operating system boot.[11]
^"sndio interface to audio devices". OpenBSD manual pages. Retrieved August 3, 2016.
^Ratchov, Alexandre (2010). "OpenBSD audio & MIDI framework for music and desktop applications" (PDF). AsiaBSDCon. Retrieved September 16, 2012.
^Arons, Barry (March 1991). "The Design of Audio Servers and Toolkits for Supporting Speech in the User Interface" (PDF). Journal of the American Voice I/O Society. Retrieved September 16, 2012.
^"OpenBSD manual pages". man.openbsd.org. Retrieved May 14, 2016.
^Alexander, Peter Lawrence; Whitear, Caroline J. (2001). How MIDI Works, 6th Edition. Hal Leonard. ISBN9780634020834.
^Ratchov, Alexandre (March 31, 2012). "The Story Of The Extra Audio Track: Recording Music With OpenBSD". Undeadly. Retrieved September 16, 2012.
sndio, software, layer, openbsd, operating, system, that, manages, sound, cards, midi, ports, provides, optional, sound, server, documented, application, programming, interface, access, either, server, audio, midi, hardware, uniform, designed, work, desktop, a. sndio is the software layer of the OpenBSD operating system that manages sound cards and MIDI ports It provides an optional sound server and a documented application programming interface to access either the server or the audio and MIDI hardware in a uniform way 1 sndio is designed to work for desktop applications but pays special attention to synchronization mechanisms and reliability required by music applications 2 sndioOriginal author s Alexandre Ratchov and Jacob MeuserDeveloper s The OpenBSD ProjectInitial releaseOctober 2008 15 years ago 2008 10 Repositoryopenbsd wbr su wbr src wbr include wbr sndio wbr hWritten inCOperating systemOpenBSD FreeBSD NetBSD LinuxTypeSound serverLicenseISCWebsitewww wbr sndio wbr org Contents 1 Features 2 History 3 Similar frameworks 4 References 5 External linksFeatures editThe sndiod audio and MIDI server is the main component of sndio It aims to fill the gap between programs requirements and the bare hardware as exposed by operating system device drivers 3 This includes 4 perform re sampling and format conversions for instance to allow a program that requires 44 1 kHz sample frequency to use a device that supports 48 kHz only mix and route the sound of multiple programs this allows multiple programs to use the audio device concurrently split an audio device into sub devices for instance allowing one program to use the front speakers and another program to use the rear speakers as they were independent simple stereo devices allow one program to record what other programs play control the volume route audio and MIDI data through the network this allows programs running on one computer to use the sound card of another computer route MIDI data between programs allowing one program to send MIDI data to another program as it was a hardware MIDI port For instance for a MIDI sequencer to control a soft synthesizer start stop and relocate synchronously a group of audio programs allowing multiple small programs to work together This can be controlled through standard MIDI Machine Control MMC protocol for instance from within a MIDI sequencer expose the sound card clock as MIDI timecode MTC allowing MIDI programs e g sequencers or MIDI hardware to be synchronized to audio streams The last few points are hooks in the sound server aiming to improve interoperability between audio and MIDI programs 5 The use of standard MIDI protocols for volume and synchronization control enables interoperability with MIDI software or hardware connected to a computer 6 History editMinimal server capabilities were added to aucat an audio stream manipulation tool and predecessor to sndiod in October 2008 7 shipping with OpenBSD 4 5 8 9 In December 2011 aucat was renamed to sndiod 10 and later shipped with OpenBSD 5 1 as the default sound server started at operating system boot 11 Similar frameworks editAdvanced Linux Sound Architecture JACK Audio Connection Kit Open Sound System PulseAudio FreeBSD PCM audio device infrastructureReferences edit sndio interface to audio devices OpenBSD manual pages Retrieved August 3 2016 Ratchov Alexandre 2010 OpenBSD audio amp MIDI framework for music and desktop applications PDF AsiaBSDCon Retrieved September 16 2012 Arons Barry March 1991 The Design of Audio Servers and Toolkits for Supporting Speech in the User Interface PDF Journal of the American Voice I O Society Retrieved September 16 2012 OpenBSD manual pages man openbsd org Retrieved May 14 2016 Alexander Peter Lawrence Whitear Caroline J 2001 How MIDI Works 6th Edition Hal Leonard ISBN 9780634020834 Ratchov Alexandre March 31 2012 The Story Of The Extra Audio Track Recording Music With OpenBSD Undeadly Retrieved September 16 2012 Ratchov Alexandre October 27 2008 Developer Blog ratchov s recent audio work Undeadly Retrieved September 16 2012 The OpenBSD 4 5 Release OpenBSD May 1 2009 Retrieved September 16 2012 Biancuzzi Federico June 15 2009 PuffyTron recommends OpenBSD 4 5 O Reilly Media Retrieved September 16 2012 src etc rc conf OpenBSD CVS December 9 2011 Retrieved May 14 2016 The OpenBSD 5 1 Release OpenBSD May 1 2012 Retrieved September 16 2012 External links edit nbsp Free and open source software portalOfficial website nbsp 13 Multimedia OpenBSD FAQ Retrieved September 16 2012 sndio 7 OpenBSD Miscellaneous Information Manual sndiod 8 OpenBSD System Manager s Manual Retrieved from https en wikipedia org w index php title Sndio amp oldid 1063121546, wikipedia, wiki, book, books, library,
