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MIDI enumeration (was: Re: getUserMedia use cases)

From: Chris Wilson <cwilso@google.com>
Date: Wed, 1 Feb 2012 10:24:30 -0800
Message-ID: <CAJK2wqXrdipXSMnpJwyRCTSb+s1qE1Qoy3iBQBoP5RKy0_xVAw@mail.gmail.com>
To: Joseph Berkovitz <joe@noteflight.com>
Cc: "Tom White (MMA)" <lists@midi.org>, Robin Berjon <robin@berjon.com>, public-audio@w3.org, Dom Hazael-Massieux <dom@w3.org>, jussi.kalliokoski@gmail.com
Forking subject.

So I can see the following enumeration/creation scenarios for MIDI:

- Enumerating MIDI interfaces present on the device (e.g. I have several
multi-port MIDI interfaces present, this lets me enumerate each input or
output, likely get unique IDs for each one (so a developer could maintain
MIDI config profile).
- Creating a virtual output port (e.g. a developer wants to create a
software synth program that, while running, creates a new device output for
other programs to enumerate) with some form of unique ID
- Creating a virtual input port (e.g. a developer wants to create a
sequencer program that, while running, creates a new device input for other
programs to enumerate) with some form of unique ID

Questions for the MIDI devs here-
- Is the "synth" output designation in Windows useful?  The #voices, type
of synth, etc?  Seems a bit overdone, to me.  It would seem like being able
to tell "this is a software synth" would be useful - although
- How about the MIDI device manufacturer/product ID?  Driver version #?
- Windows MIDI mapper.  This always seemed overblown to me; and, of course,
you can just use it as a device in Windows.  I don't think we need special
exposure, as in the Windows APIs.  Thoughts?

My off-the-cuff feeling, BTW, is that there should be a commonality of
pattern between audio port enumeration and MIDI port enumeration, but I
think they will end up as separate APIs.


On Wed, Feb 1, 2012 at 9:29 AM, Joseph Berkovitz <joe@noteflight.com> wrote:

> I also agree with Tom's suggestion that MIDI devices be considered as part
> of this sphere.
> ...joe
> On Jan 31, 2012, at 7:25 PM, Tom White (MMA) wrote:
> Chris Rogers said
> it would be good to have an introspection API to enumerate the available
> audio devices for both audio input and output.  A built-in microphone would
> be one such device.  Also commonly available is the line-in analog audio
> input on a laptop or desktop computer.  And, of course, any externally
> connected multi-channel USB or Firewire audio devices.  Some of these can
> present eight (or more) simultaneous audio input and output channels
> simultaneously.
>  It's important to not consider audio input in isolation, but also audio
> output capabilities when enumerating the devices.
> I can't help but point out that MIDI devices (software and hardware ports)
> are commonly used for audible* input/output and thus would also be a
> candidate for enumeration...
> Tom White
> www.midi.org
> *I say "audible" instead of "audio" so there is no confusion between MIDI
> and audio <g>
> ... .  .    .       Joe
> *Joe Berkovitz*
> President
> *Noteflight LLC*
> 84 Hamilton St, Cambridge, MA 02139
> phone: +1 978 314 6271
> www.noteflight.com
Received on Wednesday, 1 February 2012 18:25:00 UTC

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