Re: Channels and frames
Re: Channels and frames
- Subject: Re: Channels and frames
- From: Marc Poirier <email@hidden>
- Date: Wed, 26 Oct 2005 14:57:07 -0400
On Oct 26, 2005, at 6:39 AM, john smith wrote:
A: Tell the host my channel configuration (for instance mono ->
stereo, stereo -> stereo, no inputs -> 8 stereo outputs, etc.
etc.). The "no inputs" part can wait a bit if it's complicated,
at this point I'm concentrating on effect plug-ins.
I'm not sure what you are trying to tell the host.
I'm trying to tell my host what channel configurations my plug-in
support.
For instance, maybe the plugin is a mono plugin (mono->mono) only.
Or maybe it is a stereo plug-in. Or maybe it can do mono->mono and
stereo->stereo, but is not able to do mono->stereo (if AU supports
that at all).
Later on I'll need things like 0 inputs can 16 outputs (configured
as 8 stereo), but for simplicity I decided to leave that out for
now, and concentrate on what I consider to be the 3 major
situations for effect plug-ins:
mono->mono
mono->stereo
stereo->stereo
I do just want to throw in here that I would encourage you to
consider whether you really need to limit your effect to these
configurations. If your plugin doesn't have any inter-channel
dependencies, or if it does but they can easily scale to any same
number of inputs and outputs, then I would really encourage you to do
that. It's a nice capability of AU, and personally I feel that too
many effects don't do that when they easily could. And in fact, if
that's what you were to do, then you could forget about this
SupportedNumChannels() thing, cuz the default for effect AUs is to
not support the property, and not supporting the property = saying "I
can do any number of channels, as long as the number of inputs and
outputs are equal."
This way your effect is not arbitrarily limited to configurations
only compatible with sorta old-paradigm DAW design, rather than
working in any configuration in more flexible hosts, or automatically
supporting any sort of surround stream, etc.
In other words, in my opinion, unless you have some really compelling
reason to restrict your effect to only mono or stereo operation, I
think that you shouldn't.
That, I think, is probably part of why you don't see
SupportedNumChannels() even implemented in any of the SDK example
AUs, cuz optimally you don't want to do that.
AUs have a default format - this is the format of each of the
input and output elements that they have when they are created.
auval prints this out for each AU.
I have no idea what you're talking about, sorry. Formats? My
process call is always receiving floats, right? (when you say
"format", I think thinking bit depth and the like).
In this case, Bill is talking about the format of channel counts
(e.g. 1-in / 2-out is a format).
Marc
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