Duplex operations

[MantaTim]

I am trying to record 4 channels while also playing back to from 1 to 4 channels (only need 1) using the ALSA interface via PortAudio. There seems to be an issue with losing interrupts to the handler if this is attempted. Has anyone made any progress in this area? I can do either synchronous or asynchronous record/playback. I am able to get it to work on the stereo card (async rec/play), but the octo has issues. I am writing in C++ on a Raspberry Pi 3 using Eclipse. I currently have tried opening two streams separately and drying async and also doing 1 stream as full duplex. Results are the same. The callback for more data stops working. It works beautifully on the stereo card. Current sample rate is 48KHz/16-bit on 4 channels. I am not stuck with the PortAudio if another API works better.