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Re: MatrixMixer info
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Re: MatrixMixer info

I'd echo James' points...

This cannot be an effect - it must be a signal generator like a music device or audio file.

I'm not sure why you say this. The MatrixMixer doesn't know what is upstream as long as the input is not returning an error, whatever you connect should be OK.

It's just what I observed. I've got subgraphs feeding into the mixer and the only time I could get it to produce noise was when I had signal generators attached to each input bus. Having a music device connected to input 0 and an effect connected to input 1 meant that no sound was emitted. Disabling input 1 or connecting another music device to the effect made it work... I agree it's weird.


2. If the channel layout of the input audio unit does not match the mixer input bus then the MatrixMixer will not accept input. Use kAudioUnitProperty_StreamFormat to fix them up.

I wouldn't use the words "channel layout" here. To us, channel layout means the number and order of the channels (viz AudioChannelLayout). That matrix mixer only cares about the number.

You're right - my mistake - I'll correct the page.
Hmm... Well, this is a very confusing statement Robert.

There is nothing special about the matrix mixer here and how it handles connections (well, aside from the bugs of course:-).

A connection between 2 audio units by definition must share the format between the output of the source and the input to the destination unit.

In fact, manipulating a format on either side of any connection where that manipulation is done in any manner in which this connection is in an inconsistent state when a render call is made (ie, the connection is used) will lead to "undefined results"

Not my terminology preference.. 0xFFFFFFFF is the master. These are output channel gains.

I wasn't thinking big enough - (too focused on my little app) - of course if you've got multi-outs you'd want one fader to control them all... I'll correct this too.

All volumes in the matrix mixer can be set in Global Scope, where the elementID is set as:

Input Volume is:
(in << 16) | FFFF
Cross Point:
((in << 16) | out
Output Volume:
(FFFF << 16) | out
Master Volume:
FFFFFFFF

Its kind of nice to just think about this in one scope with just one argument (the elementID) to configure.

Bill


james mccartney
apple coreaudio


Thanks for reviewing it! :-)

Robert.
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References: 
 >MatrixMixer info (From: Robert Grant <email@hidden>)
 >Re: MatrixMixer info (From: James McCartney <email@hidden>)
 >Re: MatrixMixer info (From: Robert Grant <email@hidden>)



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