Subject: Re: [linux-audio-dev] MIDI interface latency
From: David Olofson (david_AT_olofson.net)
Date: Fri Feb 13 2004 - 02:38:51 EET
On Friday 13 February 2004 00.53, Tim Goetze wrote:
> David Olofson wrote:
> >Depends on the wire. For standard 31250 bps MIDI cables, the
> > minimum latency for a NoteOn message (status, pitch, velocity -
> > three bytes) is 0.96 ms. (It is one start bit and one stop bit,
> > right...?)
>
> yes, but you forgot there's only two bytes for the message in
> running status.
Good point - but running status (by definition) only works when you
happen to deal with multiple events with the same status. (That is,
same event type and same channel.) In real life, that means you get 3
bytes for the first note in a chord, and (if you're lucky), 2 bytes
for each of the following notes. Though this can save bandwidth and
reduce latency slightly at times, you can't really rely on it in any
truly useful way in this context.
//David Olofson - Programmer, Composer, Open Source Advocate
.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,... |
`-----------------------------------> http://audiality.org -'
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