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[Bug 18992] Running status should be prohibited

From: <bugzilla@jessica.w3.org>
Date: Tue, 25 Sep 2012 07:57:07 +0000
Message-Id: <E1TGQ0x-00013T-3O@jessica.w3.org>
To: public-audio@w3.org

Jussi Kalliokoski <jussi.kalliokoski@gmail.com> changed:

           What    |Removed                     |Added
                 CC|                            |jussi.kalliokoski@gmail.com

--- Comment #1 from Jussi Kalliokoski <jussi.kalliokoski@gmail.com> 2012-09-25 07:56:51 UTC ---
(In reply to comment #0)
> Input from Yamaha:
> ● Prohibit to receive/send ‘Running Status’ (‘Running Status’:
> http://goo.gl/Cyjtz)
> ○ Running Status is not able to stream in the spec of USB-MIDI. So the Web MIDI
> API must care the
> Running Status.
> ■ About sending MIDI Message from web browser: The iOS for example, the spec
> says that
> to set Running Status to MIDIPacket is prohibited, so Web MIDI API also follow
> the spec and prohibit to set Running Status. And also, we do NOT know the
> device which accepts Running Status, so we think this spec is appropriate to
> the Web MIDI API.
> ■ About receiving MIDI Message from external MIDI input devices: The iOS for
> example, status byte is added when the Running Status from MIDI mesages found.
> We think this spec is also appropriate to the Web MIDI API.

Interesting, somehow I didn't even know of Running Status messages. I also find
it odd that USB-MIDI doesn't support it, couldn't it just treat it as an
arbitrary message? Weird.

Anyhow, I think the course of action should be to just fix running status
messages, e.g. if the developer sends a running status message, the underlying
implementation will add the status byte and same for receiving. I'm not sure it
makes sense to explicitly prohibit Running Status messages, as if we can detect
them we can also just add the missing byte. Does that encourage people to use
running status? I doubt it, they'd have to keep track of the previous status to
keep the stream functional to no apparent performance gain even. But
"supporting" Running Status may well help someone porting old software to the
web, this could be a hard to debug issue.

As a side note, I'm rather unhappy to learn something like that even exists.
Sounds like a silly convenience addition that just makes things break. :(

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Received on Tuesday, 25 September 2012 07:59:28 UTC

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