Re: AU "offline" processing
Re: AU "offline" processing
- Subject: Re: AU "offline" processing
- From: "Jean-Alexis Montignies" <email@hidden>
- Date: Fri, 31 Jan 2003 12:34:48 +0100
On Fri, 31 Jan 2003 10:02:10 +0100
Alberto Ricci <email@hidden> wrote:
>
At 5:14 PM -0500 1/30/03, Marc Poirier wrote:
>
>I was wondering if there is a way to write AUs that input more audio than
>
>they output or vise versa. I guess that such an AU would have to be a
>
>decidedly "offline" processor since such stuff can not be done in
>
>realtime.
>
>
This is an interesting topic, and I have been wondering about this
>
too for some time.
>
The host application I am developing takes advantage of AudioUnits
>
for most of its needs, however there is a specific class of plug-ins
>
(the non-causal ones) which, as far as I understood, cannot be
>
implemented as AudioUnits and I would therefore need to lay down my
>
own plug-in format.
>
>
Would it be possible to add some extensions, in the form of
>
host-specific callbacks, to AudioUnits?
>
>
For instance, take a "Reverse" plug-in that simply takes the selected
>
waveform (of length l) and performs an operation of type y[n] =
>
x[l-n]. Of course this needs to be an offline operation once you know
>
all the sample values from 0 to l.
>
What about a delaying the output so that it becomes causal (I mean it would have
a huge latency).
Latency is not an issue in non-realtime.
Still you will need to configure your plug-in with the length of the sound (for
how much data it should wait before processing). The latency would be dependant
of this parameter.
>
I am wondering whether a "skip read head to position x" callback
>
would be useful to such AudioUnits. If the host doesn't implement it,
>
such non-causal AudioUnits would refuse to run; otherwise, they would
>
know they are being used in offline mode.
>
>
What do you think?
>
>
Best,
>
Alberto.
Jean-Alexis
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