Re: [linux-audio-dev] Re: OSC vs MIDI

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Subject: Re: [linux-audio-dev] Re: OSC vs MIDI
From: David Olofson (david_AT_olofson.net)
Date: Sat Sep 04 2004 - 02:44:28 EEST


On Saturday 04 September 2004 00.16, Steve Harris wrote:
[...]
> > I *think* bluetooth should be able to handle the bandwith
> > requirements of a mouse (125 Hz frame rate for the MX models,
> > IIRC), but 15-20 ms latency spikes would be an issue that cannot
> > be fully compensated for regardless of bandwidth. Jitter or delay
> > (buffering to eliminate jitter) would cause problems with real
> > time controllers, such as mice or musical controllers.
>
> Bluetooth can do realtime ADPCM audio, so a mouse should be no
> problem. Maybe HID controllers use a different bit of the protocol?

I dunno... Either way, ADPCM audio is just a matter of bandwidth, but
latency seems to be the issue here. 15-20 ms (in addition to
driver/OS polling latency + jitter and video buffering latency) is
unacceptable for a gaming mouse, so I suspect that messages are just
sent and handled ASAP, without timestamping. Just means you get
terrible jitter instead, which is probably *worse* than the
latency...

//David Olofson - Programmer, Composer, Open Source Advocate

.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,... |
`-----------------------------------> http://audiality.org -'
   --- http://olofson.net --- http://www.reologica.se ---


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