Audio capture bounty

This is a potentially invasive change, so I’m posting a draft here first. I would appreciate if someone high up in the hierarchy could take a look before I donate. Draft:

This bounty is about adding audio capture to libretro/RetroArch. The main purpose of this is to take audio from a physical audio input (to capture e.g. a microphone or a hardware synth) and route it into an emulated audio input inside an emulated PC. This would increase the usefulness of audio applications running under emulation. To complete this bounty:

  • Add support to RetroArch and the libretro API for capturing audio from a physical audio input
  • Allow selecting audio input device in RetroArch’s settings
  • Either hook up an emulated audio input in an existing core to the physical audio input, or write a simple test core
  • Design your implementation so that it will be relatively easy for future core developers to add the feature to new cores