AudioEngine doesn't support 48kHz sample rate

Hi,

I'm working on a project under iOS 11.0 / macOS 10.13 where i modify an audio stream. With AudioEngine and it's new manual rendering mode, i can take out audio buffers from AVCaptureOutput and modify them (audio gain, for example) before sending them over the network to a server. Moreover i can have a loopback for these buffers with an AudioUnit after the output on both platforms.

My problem actually is that AudioUnit/AudioEngine only support 44100Hz sample rate audio format where audio streams are often 48000Hz. I tryed to use a mixer node to do some downsampling, but the AudioFormat is not supported (when the samplerate is the only difference). I used an AudioConverter before the AudioEngine input node and a second one after the output node to have the right samplerate but it seems too heavy and too long.

My question is, is there a way to allow 48000Hz samplerate in the AudioEngine with performance and time limit ?

Thanks,