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Re: auval error when setting stream format on N->N plug-in
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Re: auval error when setting stream format on N->N plug-in


  • Subject: Re: auval error when setting stream format on N->N plug-in
  • From: William Stewart <email@hidden>
  • Date: Fri, 27 Feb 2009 10:17:12 -0800


On Feb 26, 2009, at 8:46 PM, email@hidden wrote:

I think auval is issuing an error before it calls Initialize - is that possible?

I don't believe so - the semantic has always been exactly what you describe - the AU can't know its state until its initialised, so that's the place where we expect to succeed or fail.


One thing it does also test is to see if it can change a format while you are initialised - in most cases this is a bad idea. So you might want to check whether you are allowing that (again have a look at AUEffectBase and the stream format calls) - perhaps that is the problem.

Otherwise, you can file a bug and attach an AU (or just send me a build of one privately) and I can have a look through it and give you some pointers

Bill



Jeremy

------Original Message------
From: William Stewart
To: Jeremy Todd
Cc: email@hidden
Sent: Feb 26, 2009 11:11 PM
Subject: Re: auval error when setting stream format on N->N plug-in

yes

You use the Initialise call to validate that the formats you are being
asked to support are actually valid. See AUEffectBase::Initialise for
a general implementation of this

Bill

On Feb 26, 2009, at 3:14 PM, Jeremy Todd wrote:

Hi,

We're preparing an Audio Unit which performs resampling, and it
supports any N->N channel configuration (any number of inputs and
outputs, as long as inputs == outputs). We're seeing an auval
failure which is pasted below, and I don't see any reasonable way to
work around it.

I think it's failing because we return noErr from ChangeStreamFormat
with 3 input channels and 1 output channels. The problem is that
inputs and outputs are set via separate calls to ChangeStreamFormat,
so we can't validate the current combination of input and output
channels until our Audio Unit is initialized. What behavior does
auval expect in this case, and how exactly is an Audio Unit supposed
to implement it?


Regards, Jeremy



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 >Re: auval error when setting stream format on N->N plug-in (From: email@hidden)

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