Re: auol and DAWs
Re: auol and DAWs
- Subject: Re: auol and DAWs
- From: Brian Willoughby <email@hidden>
- Date: Tue, 30 Mar 2010 18:03:27 -0700
On Mar 30, 2010, at 17:22, George Tourtellot wrote:
I want to create an AudioUnit that has access to all the data in
one track, and can write new data into a new track. I believe
that off-line audio units 'auol' should be good for this, but I
don't know whether any DAWs support 'auol' AUs.
Is writing an 'auol' AU a good approach? Does Logic or any other
DAW support these plugins?
You cannot have access to all of the data in one track unless you
write a DAW. It's still the responsibility of the host application
to manually feed all the data from one track into an AU, and then
capture the output elsewhere, if that's what you want. 'auol'
simply allows the host to know that an AU can be used in non-real-
time mode, potentially bouncing a track to disk in less time than
it would take to play, but sometimes taking longer than real time.
CoreAudio is always a pull model, so the speed and data flow are
always controlled by the host.
But you are right about one thing: If you find a host which has the
features you want - processing an entire track through an effects
chain and writing the new data to a new track - then an 'auol' is
the right way for you to implement the processing you want,
provided you understand that the reading and writing of data will
be handled by the AU host.
Sorry, but I sent this off a bit too quickly. You really should
mention what you're trying to do. The reason I say this is that AU
hosts, e.g. Logic, can process a track through any AU, whether it's
'auol' or not. As I tried to explain above, perhaps awkwardly, it's
the responsibility of an AU host to manage tracks, including reading
the data from files and writing output to new tracks or files.
The answer to your question about 'auol' really depends upon the
nature of the processing that you're developing. If your processing
is going to take longer than real-time, then I believe it must be
implemented as 'auol' so that the host knows the effect must be
handled "off line." However, if your processing can run in real
time, then you can just write a normal AU, and the host can still run
the effect off line if desired.
So, there's really two questions that you're interested in. One is
how to access on track to create another track, and this is an AU
host question. The other question depends upon the nature of what
you're implementing as an effect, and you really only need 'auol' if
you know that it cannot be done in real time or faster.
Brian Willoughby
Sound Consulting
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| | >auol and DAWs (From: George Tourtellot <email@hidden>) |