Re: AU MIDI Controller range bug?
Re: AU MIDI Controller range bug?
- Subject: Re: AU MIDI Controller range bug?
- From: Doug Wyatt <email@hidden>
- Date: Mon, 16 Feb 2004 12:20:05 -0800
The problem looks like AUMIDIController is expecting 14-bit values for
MIDI controls 0-31 (using MSB/LSB pairs). The internal implementation
can be configured to interpret 7-bit values but unfortunately that's
not exposed through an API.
So what happens is that a control value of 0x7F is converted to the
14-bit value 0x3F80 (0x7F << 7) and then divided by 0x3FFF (maximum
14-bit value) to get the 0-1 multiplier.
We'll fix this, probably by making 7-bit values the default and 14-bit
values configurable, but I can't say when.
Doug
On Feb 11, 2004, at 10:10, Patrick Gostovic wrote:
Folks from Apple -- Is this a bug or am I doing it wrong?
On 7-Feb-04, at 9:58 AM, Patrick Gostovic wrote:
I'm using AUMIDIControllerMapEventToParameter to map AU params to midi
controllers and then using AUMIDIControllerHandleMIDI to send midi
messages to the AU. I'm finding that a 0-127 controller value range
corresponds to less than 100% of the param's value range. Doing the
mental extrapolation, I suspect that 0-128 would span the entire
range.
The worst side effect of this behaviour is that it is impossible to
control a boolean parameter. Has anyone else experienced this?
Patrick
--
Doug Wyatt
Core Audio, Apple
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