| Title: | * * Computer Music, MIDI, and Related Topics * * |
| Notice: | Conference has been write-locked. Use new version. |
| Moderator: | DYPSS1::SCHAFER |
| Created: | Thu Feb 20 1986 |
| Last Modified: | Mon Aug 29 1994 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2852 |
| Total number of notes: | 33157 |
Can somebody tell me how the MIDI clock scheme works? Specifically,
I don't understand how the thing starts.
I read somewhere that when a sequencer is stopped, it outputs STOP
messages at the same rate that the CLOCK messages would be coming
if the sequencer was running, so that the other devices can stay
in sync.
Does the sequencer just power up outputing STOPs without any controls
being touched? (assuming that it is set up to generate external
sync).
What happens when you want to start? Does it put a START message where
the next STOP message would have been and then send CLOCKs from there
on? Is the START message, or the first CLOCK message the first beat in
the piece?
Presumably a CONTINUE message could just be substituted for a START
message where appropriate?
Thanks,
Steph
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 873.1 | attempted answers | SAUTER::SAUTER | John Sauter | Mon Jul 20 1987 13:22 | 19 |
I don't have the MIDI spec with me, but I believe that START, STOP
and CONTINUE messages are one-shots. The CLOCK messages can continue
to be sent while stopped, so that other devices can stay in sync,
though I'm not convinced of the value of this. When START is sent,
things don't really start until the next CLOCK.
CLOCK messages are sent 24 times per quarter note, so they aren't
necessarily beats, though usually they have a simple relationship
to beats.
After START, the next CLOCK is the first CLOCK of the song. After
CONTINUE, the next CLOCK is the first clock after the last CLOCK
before the last STOP. In other words, the receiver ignores CLOCK
between STOP and CONTINUE.
I hope the above is accurate--it's from memory of the MIDI spec,
and it's been too long since I read it. If you need reliable answers,
I recommend you read the spec.
John Sauter
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| 873.2 | Enter a title for your reply: | ECADSR::SHERMAN | one rubber nose! | Mon Jul 20 1987 16:35 | 6 |
re -.1: The value I find with the clock continuing is that, for
example, my drum maching continues to respond to the tempo I've
set in the sequencer. So, I can work out drum suff at tempo on
the drum machine, then dump this stuff to the seqeuncer. FWIW
Steve
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