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

[David Olofson]

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

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