Revisited Re: AudioUnitSetParameter question
Revisited Re: AudioUnitSetParameter question
I do not understand why Reverb Room-Type is a property and not a parameter.
It seems that Room type is very specific to a particular class of plug-ins,
namely reverb. Why then is there a Room-Type property?
It would certainly make for cleaner, less special-cased code.
Also, why is there an enum type but no way to get at the strings needed to
display the meaning of the values? This seems like a missing part of the
audiounit spec. Any comments welcome.
Thanks,
Jeremy
>
From: Chris Rogers <email@hidden>
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Date: Fri, 15 Feb 2002 02:58:09 -0800
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To: email@hidden
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Subject: Re: AudioUnitSetParameter question
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>
John,
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>
You're not doing anything wrong. There is a bug particular to the reverb
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AudioUnit which makes it ignore parameter changes. You still can set
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a particular preset of the reverb with the kAudioUnitProperty_ReverbRoomType
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property using one of the enums from AudioUnitProperties.h
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>
enum {
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kReverbRoomType_SmallRoom = 0,
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kReverbRoomType_MediumRoom = 1,
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kReverbRoomType_LargeRoom = 2,
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kReverbRoomType_MediumHall = 3,
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kReverbRoomType_LargeHall = 4,
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kReverbRoomType_Plate = 8
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};
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>
Sorry about the trouble. We expect this will be fixed.
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>
Some other improvements to the reverb, perhaps improved quality, etc.
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may be coming as well...
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>
Chris Rogers
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CoreAudio
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>
>
> I'm trying to use AudioUnitSetParameter to set some of the options
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> on the built-in reverb audio unit, and I must be doing something
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> wrong because it doesn't seem to be working.
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>
>
> First, I use AudioUnitGetProperty with
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> kAudioUnitProperty_ParameterList, and then AudioUnitGetProperty with
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> kAudioUnitProperty_ParameterInfo to get the list of parameters that
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> the reverb audio unit supports.
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>
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> So, as an example, "decay time" has a parameter ID of 0, min value
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> of .1, and max value of 5. I see by the flags that it is in the
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> global scope and both readable and writable.
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>
>
> If I try to do the following, however, it doesn't seem to be working:
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> theStatus = AudioUnitSetParameter(reverbAU, 0,
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> kAudioUnitScope_Global, 0, [sender floatValue], 0);
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>
>
> When I say "doesn't seem to be working," I mean that I can't hear
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> any difference between the max value, the min value, or anything in
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> between. (The same goes for all the other properties.) There are no
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> errors reported from the calls as far as I can tell.
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>
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> The things that I think might be wrong in that call are the
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> inElement value, and the inBufferOffsetInFrames (arguments 4 and 6).
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> Should they be something other than zero?
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>
>
> If anyone has ideas on why this isn't working, I would appreciate
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> hearing about it.
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>
>
> --john
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