Simple code to use an effect
Simple code to use an effect
- Subject: Simple code to use an effect
- From: "Jean-Philippe Leblanc" <email@hidden>
- Date: Sun, 17 Feb 2002 23:02:04 -0800
Hi,
I modified the DefaultOutput Unit sample code in order to add effect to the
playback so I can test the ones I wrote (is there a simple app that would
let me do that?) I don't think that I am too far away from having it working
but it still doesn't playback after much efforts trying.
Original code is UsingAudioConverterNoAC.cpp (since I use default output
32-bit float stereo 44100.)
I added an effect au (matrix reverb).
I feed the matrix render function with the sin generator in 32-bit float
format. I also setup the AudioStreamBasicDescription for the effect au (same
as the output au.)
Then I do :
AudioUnitConnection theConnection;
theConnection.sourceAudioUnit = theEffectUnit;
theConnection.sourceOutputNumber = 0;
theConnection.destInputNumber = 0;
verify_noerr(AudioUnitSetProperty(theOutputUnit,
kAudioUnitProperty_MakeConnection,
kAudioUnitScope_Input,
0,
&theConnection,
sizeof(theConnection)));
Is that the way it should be? In particular, the scope is input, so I need
to give a source, right? The command could have been clearer if it was given
an sense of direction. Connection doesn't say much about the way of the
stream. Just a suggestion.
What are the sourceOutput and destInput numbers representing? I can't find
any relation anywhere to with these number used here. I must have looked a
dozen times in the headers and the pdfs. If I use 1 instead of 0, then the
effect won't be pulled. Why?
In order to find out if the filter gets pulled, I built the sample effect au
in the SDK and put a debug statement in the process loop. I get there. But I
still can not hear anything. However since I invoke start on the default
output au only, it is pulling its source correctly or it wouldn't reach the
breakpoint in the effect au. Right?
Is there an order to do things. Can I make the connection at anytime (as
soon as I get two au refs) and then change the properties?
Recently, someone was asking what needed to be ehnanced regarding documents.
May I suggest that the coreaudio.pdf gets more details about the Audio Units
stuff. Right now, it's about the same as reading the headers. Actually, it
is the comments in the headers.
About the coreaudio pdf, the AudioStream API is totally missing from the
document too.
Thanks for your help.
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