Re: Multi-bus AU's and Logic
Re: Multi-bus AU's and Logic
- Subject: Re: Multi-bus AU's and Logic
- From: William Stewart <email@hidden>
- Date: Mon, 29 Nov 2004 15:06:57 -0800
There's some history here that has been reiterated a few times.. Basically,
the problem now is that AU's that publish a second (or more) output buses
that never do anything with them - so you get garbage whenever you try to
use them - that's what we need fixed.
On 29/11/04 2:42 PM, "graffiti" <email@hidden> wrote:
> Is it just AU plugin developers who have mistaken this, or some of the host
> developers too?
> If we change the bus count in our AUs, is it possible that stereo plugs will
> appear as Mono in some hosts? Or do all hosts use the coreaudio api 100% and
> therefore it shouldn't be an issue?!
This particular problem was NEVER an issue that I knew of - and actually is
a great summary of the confusion between an Audio Unit's output bus
capability and the number of channels on a given bus.
> Oh, and if we use the latest SDK, will our AUs still function on OX10.2?
As far as I know - read, there's nothing we've changed that should cause
problems....
Oh - and there's nothing in the SDK that will make this automatically go
away either - if you declare that you have more than one output bus, but you
don't do anything with it, then you will still have the problem - ie. You
have to make the change by declaring how many buses you really deal with
(and then dealing with those buses in the Render call)
Hope that helps
> Just wanted to check :) Thanks,
Sure - better to be safe than sorry.
Bill
>
> Kieran.
>
> William Stewart wrote:
>> Multi-bus AU's and Logic In chatting with the Logic engineers, we came to
>> the realisation that one of the problems they are having to deal with are the
>> incompatible versions of the AU Instruments...
>>
>> The problem this causes is that if Logic wires things up the ³correct² way
>> which it does in Logic 7, then these older AU¹s cause noise to be generated
>> on their alternate buses. (These are the AU¹s that incorrectly assumed that
>> the number of outputs in the AU implementation classes meant ³number of
>> channels² - when it actually means ³number of buses²) - so these AU¹s create
>> 2 ouput buses (instead of 1 output of 2 channels)... Because the AU is doing
>> nothing with this second bus, its completely random noise that is coming out.
>> The fix is simple just change the numOutputs argument in your constructor
>> to 1!
>>
>> As this problem means that noise is generated on the second bus it is a very
>> unsatisfying user experience (to put it mildly), and causes ongoing problems
>> as Logic tries to move over to support the valid multi-bus AU¹s that are
>> available. This is also a problem that auval cannot pick up on, as the AU
>> essentially looks fine (and auval can¹t determine of course if the produced
>> audio is good or bad).
>>
>> So, we need all of the AU¹s that have been developed this way to be fixed.
>> We¹re compiling a list of the problematic AU¹s (with their version numbers
>> that we¹ll be making available) - I¹m hoping that most, if not all, of the
>> developers of these AU¹s are on this list and will fix these AU¹s and make a
>> fixed version available ASAP.
>>
>> Thanks
>>
>> Bill
>>
--
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