Re: AU sidechain inputs?
Re: AU sidechain inputs?
- Subject: Re: AU sidechain inputs?
- From: Bill Stewart <email@hidden>
- Date: Mon, 07 Oct 2002 18:07:13 -0700
This is primarily a documentation issue for us (and I'll make sure we
address it:)
An effect unit is "by convention" required to support only a single main
input and output bus (elementID) - where elementID == 0
Additional busses that maybe found through the BusCount property on either
or both input and output scopes are presumed to be "side chains" for the
effect.
However, we are not explicit about this - and as the audio unit creates the
busses for both input and output there is no enforceable restriction here
about what those busses actually are (nor do we want them to be)...
Ultimately, what arbitrates a connection is whether the format that is
published for a given bus is provided by the host.
One way that we haven't yet implemented (but I think is reasonable) to
distinguish FOR THE USER the intention of a published bus. The AudioUnit
would provide names for its busses...
Thus you could have:
"Main Bus"
"Side-Chain Modulator bus"
Or in the case discussed below:
"First Input"
"Second Input"
Then really it is up to the host to query an AudioUnit on its number of in
and out busses, and present a way for a user to choose which audio goes
to/from which in/out bus
Does this seem a reasonable solution?
Bill
on 7/10/02 4:44 AM, Richard Dobson wrote:
>
This raises a very important question for me about the assumptions for
>
both hosts and plugins. With VST, a plugin can have any number of inputs
>
and outputs, and I have, for example, plugins under development that
>
will, for example, take two input signals, and morph/cross-syntehsize
>
them to a single output (you can naturally imagine this scaled to
>
stereo, etc). Now in a graph-oriented application like AudioMulch, the
>
plugin is simple to use - you just wire up the connections as you want.
>
>
>
However, in a trak-based DAW, this is impossible, unless you can assign
>
multiple tracks to selected inputs of the same plugin. In DAW-speak this
>
would be a 'side-chain': but even that term presumes a hierarchy,
>
whereas as far as I am concerned I am simply processing two signals to
>
create one output. Having to define one input as a 'side-chain' seems
>
arbitrary, and potentially restrictive. I may or may not want the output
>
to comprise the same 'track' as one of the inputs - which a DAW might
>
conceivably force me to do.
>
>
>
So my comment on this question is that it really implies a limitation of
>
the host, rather than of the plugin API as such; and needless to say I
>
hope very much that the said API will not be designed with the
>
assumption that all hosts are DAW-style, with their concomitant limitations!
>
>
>
>
Richard Dobson
>
>
>
>
Andy wrote:
>
>
>> If I'm making a compressor or vocoder effect plug-in (and I am!), is
>
>> there
>
>> a way to hint to the host that one of the inputs is a sidechain, and
>
>> should
>
>> normally be connected to a different audio source to the other input(s) ?
>
>> (and in the case of a compressor, it's optional that it is connected).
>
>
>
>
>
> I've been wondering about this too. I've got several AUs that have
>
> modulation inputs.
>
> It would be nice to have some way of differentiating them from simple
>
> audio ins.
>
> _______________________________________________
>
> 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.
--
mailto:email@hidden
tel: +1 408 974 4056
__________________________________________________________________________
"Much human ingenuity has gone into finding the ultimate Before.
The current state of knowledge can be summarized thus:
In the beginning, there was nothing, which exploded" - Terry Pratchett
__________________________________________________________________________
_______________________________________________
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.