AUGraph with multiple Output Units

Question

Created Nov ’15

Replies 1

Boosts 0

Participants 2

Well, the title of the subject may sound awkard as it is known that when trying to include two output units in an AUGraph one gets OSStatus code -10862: "Audio processing graphs can only contain one output unit." And that is exactly the error I am getting at implementing the Audio Unit diagram below (PDF link)

https://drive.google.com/file/d/0B549G1c1AK95eUlGS3dRUkJ6R2s/view?usp=sharing

I have also implemented a "working" workaround consisting of two AUGraphs (also in that PDF), but both AU streams coming from the same file are obviously not syncronized, and that is a big problem for the whole application.

I contacted Apple support and I am getting from them twice the same answer "An AUGraph may have a SubGraph to manage a discrete collection of AUs created using AUGraphNewNodeSubGraph - however two independent AUGraphs cannot be “linked” together." So, subgraphs seem to be the solution for this, but ... how to decompose such a AU system into subgraphs each with only one output unit?! Impossible in my eyes. Or am I missing something?

Any advice/feedback is really appreciated.

Boost

Answer 1

NB Systems OP

Dec ’15

the DSP structure of an AU is one (1)...

If you have more than 1 channel, you have to deal with the buffer of you DSP procedure - Your can try to read the file / stream description to get informations about the file / stream - it includes the count of channels and more...

When you schematic drawing showing on of the two results (the outputs) - you have to dealing with the compatibility of channels for IO and the DSP.

Hope this helps :-)

best regards.

0