Editing MIDI (section)

===Interfaces===
A computer MIDI interface's main function is to synchronize communications between the MIDI device and the computer.<ref name="indiana.edu"/> Some computer sound cards include a standard MIDI connector, whereas others connect by any of various means that include the [[D-subminiature]] DA-15 [[game port]], [[USB]], [[FireWire]], [[Ethernet]] or a proprietary connection. The increasing use of [[USB]] connectors in the 2000s has led to the availability of MIDI-to-USB data interfaces that can transfer MIDI channels to USB-equipped computers. Some MIDI keyboard controllers are equipped with USB jacks, and can be connected directly to computers that run music software.

MIDI's serial transmission leads to timing problems. A three-byte MIDI message requires nearly 1&nbsp;millisecond for transmission.<ref>Robinson, Herbie. "[http://lists.apple.com/archives/coreaudio-api/2005/Jul/msg00120.html Re: core midi time stamping] {{webarchive|url=https://web.archive.org/web/20121028045258/http://lists.apple.com/archives/coreaudio-api/2005/Jul/msg00120.html |date=28 October 2012 }}". ''Apple Coreaudio-api Mailing List''. Apple, Inc. 18 July 2005. 8 August 2012.</ref> Because MIDI is serial, it can only send one event at a time. If an event is sent on two channels at once, the event on the second channel cannot transmit until the first one is finished, and so is delayed by 1&nbsp;ms. If an event is sent on all channels at the same time, the last channel's transmission is delayed by as much as 16&nbsp;ms. This contributed to the rise of MIDI interfaces with multiple in- and out-ports, because timing improves when events are spread between multiple ports as opposed to multiple channels on the same port.<ref name="WalkerTime" /> The term ''MIDI slop'' refers to audible timing errors that result when MIDI transmission is delayed.<ref>Shirak, Rob. "[http://www.emusician.com/news/0766/mark-of-the-unicorn/140335 Mark of the Unicorn] {{webarchive|url=https://web.archive.org/web/20140323225235/http://www.emusician.com/news/0766/mark-of-the-unicorn/140335 |date=23 March 2014 }}". ''emusician.com''. New Bay Media. 1 October 2000. Web. Retrieved 8 August 2012.</ref>