5 Jul
2010
5 Jul
'10
12:05 a.m.
On Sun, 2010-07-04 at 23:35 +0200, fons(a)kokkinizita.net wrote:
Well, at least those sound cards that provide both
audio and midi
*could* do this - timestamp incoming midi and provide that info
in some way, and requiring similar time stamps for outgoing midi.
Could do it even with separate midi and audio cards, as long as the midi
RX ISR can somehow grab a timestamp from the audio card driver (in an
interrupt context), and as long as the midi RX ISR is getting serviced
with negligible latency (Otherwise you need to timestamp in hardware).
In reality is is probably only practical in an embedded context where
you have total control over the hardware.
Note that even with this you will have some jitter due to the way a UART
typically over samples to get the centre location of each bit (But at
midi rates this should only be measured in tens of microseconds).
MIDI on general purpose hardware with a general purpose OS is hard to
get really right.
Regards, Dan.