How to Mix Two Different Audio Sources

[Moriquendi]

Hello forum,

Is it possible to mix two audio inputs into one? Let's say I have a talkie and when PTT(push-to-talk) is activated, it streams audio to network(lets say udp://@:24100 where the audio is streamed to). On a PC, I want to mix this network stream and the output of the PC microphone and save it to a file. But I dont to want append these audios one and after. I want to merge/overlap them synchronously.

I think #gather does what I want to achieve but its says this works if all streams match. So should I try to first transcode microphone output into the audio format of UDP stream and then try to #gather both audio? Any help would be appreciated.

Cheers.