[sdiy] USAMO

Colin f colin at colinfraser.com
Thu Mar 26 17:12:26 CET 2015


> It seems crazy in this day and age that MIDI data cant be sent at the
right
> time given how slow the final 5-pin DIN connection baud-rate is, compared
to
> modern USB and CPU speeds!

For sending MIDI clock only, USB MIDI is actually worse than serial MIDI.

> I always thought that MIDI data *was* time-stamped and sent ahead of time
> to the MIDI interface.  Isn't that what Roland's MPU401 interface was
> supposed to achieve?  Or is it just that nobody chooses to do it that way,
and
> just uses a crappy windows driver and FIFO mode instead?

There have been Steinberg and E-Magic interfaces with proprietary
time-stamping, but never anything that could be shared.
The MMA missed a trick by not including it in the standard MIDI device
class.
A PC with a driver running a MIDI interface over a USB bus with a frame rate
of 1ms at best, driven by a process that can ask the kernel nicely for a
callback every 1ms but isn't necessarily going to get it, is never going to
do better than 2ms jitter.

Cheers,
Colin f






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