Re: bus count and channel info confusion
Re: bus count and channel info confusion
- Subject: Re: bus count and channel info confusion
- From: William Stewart <email@hidden>
- Date: Tue, 20 Jul 2004 19:33:19 -0700
Interesting discussion... posting again in two parts because its too
big...
PART 1
Comments below...
On 16/07/2004, at 7:15 AM, Marc Poirier wrote:
>
Hi Frank. I don't know about some of these, but I will respond
>
(hopefully correctly) about the ones that I think I know about, to
>
start with...
>
>
>
On Jul 16, 2004, at 5:13 AM, Frank Hoffmann wrote:
>
>
> 1. Mono Audio Effect
>
> Input Bus Count: 1, not writeable
>
> Output Bus Count: 1, not writeable
>
> Channel Info: {1,1}
>
>
Correct.
>
>
> 2. Stereo Audio Effect:
>
> Input Bus Count: 1, not writeable
>
> Output Bus Count: 1, not writeable
>
> Channel Info: {2,2}
>
>
Correct.
>
>
> 3. Audio Effect with the ability to do Mono in Mono, Mono in Stereo
>
> and Stereo in Stereo processing
>
> Input Bus Count: 1, not writeable
>
> Output Bus Count: 1, not writeable
>
> Channel Info: {1,1}, {1,2}, {2,2}
>
>
Correct.
>
>
> 4. Audio Effect with any ability to process any number of channels
>
> where the number of input channels has to be equal to the number of
>
> output channels
>
> Input Bus Count: 1, not writeable
>
> Output Bus Count: 1, not writeable
>
> Channel Info: {-1, -1}
>
>
Technically correct, but the preferred way (and way which you should
>
recognize since it's what most N-N effects do) is to not supply any
>
Channel Info, it will return an error from GetPropertyInfo() because
>
the property is not being supported.
>
>
> 5. Audio Effect with the ability to process any number of channels
>
> where the number of input channels has not to be equal to the number
>
> of output channels
>
> Input Bus Count: 1, not writeable
>
> Output Bus Count: 1, not writeable
>
> Channel Info: {-1, -2} or {-2, -1}
>
>
Correct.
>
>
> 7. Audio Effect that processes stereo only, but has a side chain
>
> input that can be mono or stereo.
>
> Input Bus Count: 2, not writeable
>
> Output Bus Count: 1, not writeable
>
> Channel Info: Not possible to describe
>
>
Yeah, I think that you just can't do this, though I'm not sure about
>
that.
I believe this should be described as Reaktor (and Reaktor FX)
describes its channels:
Input Bus Count: 1, writable
Output Bus Count: 1, not writable
Channel Info: { -4, 2 }
Then the host can decide to use either 3 or 4 of the input channels as
the user wants. The AU can easily deal with this situation even if the
host configures this as 4 mono inputs too, I believe.
By formatting the first bus to be stereo input (and output), then I
think the AU is providing a pretty reasonable hint to the host about
its preferred configuration (and some hosts may even decide to use this
as the starting off point when presenting dynamically configurable
AU's).
>
>
> 8. Stereo Synth (Music Device)
>
> Input Bus Count: 0, not writeable
>
> Output Bus Count: 1, not writeable
>
> Channel Info: {0, 2}
>
>
Correct. * (see footnote)
>
>
> 9. Music Device that can output Mono or Stereo
>
> Input Bus Count: 0, not writeable
>
> Output Bus Count: 1, not writeable
>
> Channel Info: {0, 1}, {0, 2}
>
>
Correct.
>
>
> 10. Music Device that can output Mono or Stereo and has a side chain
>
> input, which can be mono or stereo
>
> Input Bus Count: 1, not writeable
>
> Output Bus Count: 1, not writeable
>
> Channel Info: {0, 1}, {0, 2}, {1, 1}, {1, 2}, {2, 1}, {2, 2}
>
>
Assuming the input is a "sidechain" and optional, correct. Otherwise
>
it shouldn't have any of the {0, X} configurations. Also, it may
>
choose to not support mixed {2, 1} or {1, 2} configurations if the i/o
>
are tied together in some way. Anyway, depends on the AU, but I could
>
see either of those possibly being the case.
>
Bill
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