- From: Chris Wilson <cwilso@google.com>
- Date: Fri, 2 Mar 2012 12:35:12 -0800
- To: James Ingram <j.ingram@netcologne.de>
- Cc: public-audio@w3.org, Chris Rogers <crogers@google.com>
- Message-ID: <CAJK2wqUF1U3OeF8G1+bUUiB2XQs4omfNjZwbHrh2skiRVWZSDQ@mail.gmail.com>
On Fri, Mar 2, 2012 at 4:27 AM, James Ingram <j.ingram@netcologne.de> wrote: > Right. This is true of the Windows APIs as well; when received and sent, >> the messages are time-stamped. This is for use by the underlying MIDI >> driver and hardware; it's not part of the MIDI protocol itself. >> > > If its not part of the MIDI protocol itself, then it should probably be > hidden behind any new (JavaScript) W3C MIDI API. Yes? > As others stated - the API exposing this info is fairly critical to getting timing accuracy. > So I'll stick to my guns, and repeat that MIDI commands (in the MIDI > protocol) don't use time stamps. SMFs use the methods outlined by Anthony > yesterday [2]. These generally consist of projecting a series of nominally > regular ticks (of some sort) onto the other messages in the file. > The MIDI >protocol< doesn't use timestamps. MIDI APIs typically do, in order to minimize latency errors. > And I'd like to have a function in the JavaScript API which would allow me > to set the frequency with which the clock-ticks are sent. (i.e. give me > control over how fast to play a MIDI file.) > You've actually hit the nail on the head - it's relatively easy to write code that would inject a beat clock from the API. However, you're quickly going to want to interface with that beat clock - e.g., have the transport controls, time code, etc, all directly represented - and that becomes a fairly large and complex API surface in order to enable all possible DAW/sequencer/synth designs. > This is perfectly good MIDI language, but I have to say that my toe-nails > curl up when I see MIDI talking about "tempo" and "quarter notes". MIDI > uses "beat" and "quarter note" interchangeably -- as in "beats per minute" > and "quarter-notes per minute". This is the kind of confusion that got > 20th century music notation into big trouble. > Noted. I'll try to avoid saying "quarter note", which I don't think is used outside of SMF. > Apropos age: I'm not very interested in the Standard MIDI File format. Its > a binary format, and there's a lot of software and better expertise than > mine out there for dealing with it. I think we only have to support it for > historical reasons. > I actually think SMF is interesting for more than historical reasons, but I think it's a lot more interesting as a publicly available library. -C
Received on Friday, 2 March 2012 20:35:41 UTC