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: Mon, 26 Jul 2004 11:02:55 -0700
On 26/07/2004, at 6:28 AM, Stefan Gretscher wrote:
>
Am 23.07.2004 um 21:25 schrieb William Stewart:
>
> For example. Lets say that I have an effect that can be set to any
>
> num channels in to out as long as they are the same (this is the
>
> default for most effects).
>
>
>
> Now, I have a 6 channel stream.. Somewhere above my effect that
>
> stream has some kind of surround/spatial characteristic. But the
>
> effect doesn't know about this - it just takes 6 channels in and
>
> outputs 6 channels.
>
>
>
> It does NOT support the AudioChannelLayout property. It doesn't need
>
> to because it is just processing channels with no implications to if
>
> of where those channels are spatially.
>
But isn't that exactly what old Logic multichannel does: processing 6
>
(or 8) channels on one bus without any spacial information?
>
I don't understand the conflict with Pavol's suggestion here.
>
>
> Therefore, we've specified that support of the ACL is optional and
>
> should only be supported by those AU's that are doing something based
>
> on spatial locations.
>
According to this statement, what is the problem with the old Logic
>
mode:
>
one bus, 8 outs on that bus, no spacial info = 8 plain channels.
>
In what way does this conflict with the specs?
In the first case, the 6 channels are still somewhere before it, a
surround stream.. i.e. the channels were generated by an AU that is
doing surround and publishes an ACL (for example AUMatrixReverb's
surround outputs). We're also talking about an effect that takes audio
in to audio out.
>
> I guess you could argue that an AU Instrument is generating audio and
>
> typically not processing it, so if it is outputting more than 2
>
> channels it is likely to be doing so with some spatiality assumed.
>
> But I'm loathe to make this a rule...
>
Old Logic mode does not assume spaciality, it's using 8 equally
>
handled channels.
>
So in my opinion we are not creating a new rule here but follow the
>
existing ones.
The problem is that these 8 channels are really a collection of stereo
and mono channels. If this is the only way (which Logic encourages by
its implementation) that a synth can output more than one set of these,
then it is *not* implementing this the way we've described and
expected.
For the common case, we've expected that these streams be provided to a
host through different buses from the AU. After all, that is generally
what happens to these 8 channels after they have left the AU correct?
Logic allows you to route them to different effect chains, etc, as
stereo or mono buses? That's why we created the concept of both in and
out scopes having the possibility of more than one bus.
However, doing it Logic's way I've suddenly got an AU that says it does
8 channels, but doesn't give me any indication about what those 8
channels are. I've also as a host described a particular way that now
*all* hosts have to work and furthermore that is requiring work on the
host side that can easily (and is already internally) being done by the
AU.
I agree with what Pavol was saying, that a synth that is capable of
outputting more than 2 channels *should* publish an ACL to describe
this capability.
I was (probably clouding the issue somewhat) making the point that this
is not a hard and fast rule that can be expected to be applied across
all AU's.
Bill
>
>
Best,
>
>
Stefan Gretscher
>
>
plug-in development & 3rd party plug-in support
>
Emagic Soft- & Hardware GmbH
>
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