4 Sep
2004
4 Sep
'04
9:10 a.m.
On Sat, Sep 04, 2004 at 01:44:28 +0200, David Olofson wrote:
On Saturday 04 September 2004 00.16, Steve Harris
wrote:
[...]
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...
There cant be any latency jitter on the audio... I would guess that either
that part of the protocol is reserved for audio in some way, or the
logitech implementation is just rubbish.
- Steve
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?