Re: 'aufc' type AU not appearing in AULab
Re: 'aufc' type AU not appearing in AULab
- Subject: Re: 'aufc' type AU not appearing in AULab
- From: tahome izwah <email@hidden>
- Date: Fri, 23 Sep 2011 16:01:54 +0200
Thank you for your reply Paul. So how would you have an 'aufx' plug in
do time stretching then? As I read Bill's reply on a related question
(quoted below) this will need to be done by an 'aufc' type plug in.
Also, both AUVarispeed and AUTimePitch are of type 'aufc', which led
me to believe that this is a requirement for this task.
Thanks again,
--th
2008/10/16 William Stewart <email@hidden>:
> Different audio units have a different notion of I/O limitations
>
> Effect and Music Device units are expected to behave as "real-time" - that
> is that they will ONLY request input that matches their request for output.
> So, that precludes the ability to have different sample rates on input and
> output, or a varispeeding type of rate control. This covers the au types of
> 'aufx', 'aumf', 'aumd', 'aupn'. Mixers are also expected to behave in this
> manner as well.
>
> For processing that can have a difference between in and out requirements
> are of the format converter type (and the offline type) - 'aufc' or 'auol' -
> output units (auou) also fit into this category. Apple's list of format
> converter's include a generic AUConverter (that can do sample rate
> conversions), AUVarispeed and AUTimePitch
>
> The reason for this distinction is due to the hosting requirements for an
> audio unit that can pull more or less input than its output. In AULab (to
> take an example) it allows only "effects" to appear in audio chains where
> the source is either a music device or an audio input. However, if the
> source is a generator unit, we allow converter units as many generator units
> (think of a file player or a noise/tone generator) are not really real-time
> limited.
>
> Finally, to distinguish between a format converter (and a generator) unit
> that might be useful to use within a hosting context, the unit publishes a
> custom view - even if it is only a republishing of the generic view. For
> example, the varispeed and time pitch are quite useful audio units to use in
> a host app, so they publish a custom view which is the generic view.
> AUFilePlayer also publishes its own view.
>
> The other generator and aufc units we ship are not useful without some kind
> of custom handling or UI - so they don't have a custom view and won't show
> up in a hosting app.
>
> Finally - for implementing one of these (aufc or generator) you need to
> start from AUBase. AUEffectBase is not appropriate for this kind of audio
> unit.
>
> Bill
>
2011/9/23 Paul Davis <email@hidden>:
> On Fri, Sep 23, 2011 at 9:41 AM, tahome izwah <email@hidden>
>> Does Logic (or any other host) support this type of plug in, and if
>> so, how do I instantiate it from there?
>
> "Data format converter units ('aufc'), which change characteristics of
> an audio data stream such as bit depth, sample rate, or playback
> speed"
>
> this makes almost no sense inside a realtime host. certainly
> ardour/mixbus won't load such plugins. note that if you were doing
> just bit depth reduction or playback speed as an effect, then aufx
> would presumably be more appropriate. but changing sample rate really
> implies changing the number of samples representing a given unit of
> time, and this isn't viable inside a realtime host that expects
> samples in = samples out.
>
> i would just use 'aufx' and be done with it. i think that 'aufc'
> plugins are primarily intended for offline, non-streaming purposes
> (i.e. hardly used at all).
>
> --p
>
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