For my current project I spend the last days writing a “plugin” for capturing the speaker-audio with WASAPI Loopback.
Thinking whether I should release that as a proper plugin. As I have more then enough to do at the moment I would only do so if there’s any interest in it. After all the community has done for me, that’s the least I can offer. Seems that there is no way to record out-audio from UE4.
Currently my implementation has two supported output codecs, PCM WAV and OGG Vorbis, which I use for our mpeg-4 video-capture.
If there’s interest I can also implement a live data callback system for audio visualizers or other stuff.
Could also integrate it into @eXi 's sound visualizer to enable live-visualization.
If you have general questions, I would answer those gladly too