Re: Attn AU host-makers - PropertyListeners
Re: Attn AU host-makers - PropertyListeners
- Subject: Re: Attn AU host-makers - PropertyListeners
- From: Chris Reed <email@hidden>
- Date: Fri, 22 Nov 2002 11:36:23 -0600
This, along with your recent request to add MusicEffect support to AU
hosts, makes me think that perhaps we need a "Guide to Writing Audio
Unit Hosts" paper or FAQ. It should cover everything that's been
discussed here in depth.
I would be willing to help write this document, but I don't want to be
the only one working on it. And it would also be great to have Apple's
support here, like hosting or linking it on the CoreAudio documentation
site.
(And perhaps there should be a similar "Guide to Writing Audio Units"
that covers the other side of the equation.)
-chris
On Friday, November 22, 2002, at 11:17 am, Marc Poirier wrote:
Hi. I'm writing because I'd like to encourage AU host makers to please
install property listeners for the kAudioUnitProperty_CurrentPreset and
the kAudioUnitProperty_Latency properties.
Many plugins ways of managing their presets internally. In
particular, a
lot of synths offer a preset browser/loader in their UIs, and some
plugins
(like most of mine) respond to MIDI program changes to switch between
presets. So unless the host installs a property listener for
kAudioUnitProperty_CurrentPreset, the host's representation of the
current
preset does not reflect the actual selection.
The Latency property can change in some plugins via parameter changes
(for
example, in my Scrubby effect and Tom's Geometer effect), so a listener
for that property is also important.
I have checked in Logic, Rax, and Beyond, and none of these hosts
install
property listeners for either of these. Rax probably doesn't worry
about
latency (which makes sense, given what it does), but Logic and Beyond
should have property listeners for Latency, and all should do
CurrentPreset.
Also, I think that a nice thing about the AU API is the fact that
parameter configs can change on the fly (the number of parameters,
their
properties, etc.), so perhaps it would be nice if hosts also installed
property listeners for kAudioUnitProperty_ParameterList,
kAudioUnitProperty_ParameterInfo, and
kAudioUnitProperty_ParameterValueStrings, although I personally don't
think that's as important and Latency and CurrentPreset (although I
probably would if I had any plugins that changed parameter configs)...
Thanks for listening to my rambling,
Marc
_______________________________________________
coreaudio-api mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/coreaudio-api
Do not post admin requests to the list. They will be ignored.
_______________________________________________
coreaudio-api mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/coreaudio-api
Do not post admin requests to the list. They will be ignored.