How to implement AudioUnit descended from MusicDeviceBase with 1 output and 2 inputs? (it generates silence in Digital Performer)

Question

I have a really weird issue here. I implemented an AU, using MusicDeviceBase. If the AU has 1 input bus and 1 output bus, it works everywhere. If it has 2 inputs (main and sidechain input), it works too, but not in Digital Performer - it seems working fine, but DP just interprets the output as silence. So it must be some AU buffering problem. I do this in the overriden Render method:

• PullInput for all inputs and retrieve the buffers via GetBufferList
• get output buffers via GetBufferList for the single output
• then just render all the stuff from input to output...

The output buffers are definitely not silent, but DP shows nothing...

Any ideas? Thanks in advance!

Answer 1

Ok, so the reason was, the "silent" tag. So this is the solution:

ioActionFlags &= ~kAudioUnitRenderAction_OutputIsSilence;