https://www.libretro.com/index.php/retroarch-1-6-0-released/
Windows version improvements
Windows users now can use the WASAPI audio driver for the first time, which should allow for lower-latency audio. And if that isn’t enough, there is another successfully completed bounty, a RawInput input driver, which should allow for lower-latency low-level input.
Vulkan renderer
The Vulkan renderer has received some improvements. It should now support Unicode font rendering and render certain accented French characters correctly.
Localization
There have been several localization improvements. The German and Japanese translations have been updated, and Korean text should finally display properly.
Audio mixer
Now here is a real standout feature we are excited to tell you about! RetroArch now has a built-in audio mixer which allows you to mix up to 8 separate audio streams and splice them together with the game’s audio. To put it more simply, this means custom soundtrack support from inside RetroArch!
Currently, there are a couple of limitations here –
1 – The only supported audio files so far are Ogg Vorbis files (.ogg) and regular Wave files (.wav). Over time, there will be more audio codecs supported.
2 – The audio mixer tracks will only play when the game is running. They will not play while inside the menu, unless you turn off ‘Pause when menu activated’ (Settings -> User Interface -> Menu).
3 – You can only mix up to 8 simultaneous audio streams so far. Looping is not yet available, neither is pausing an audio stream or changing a stream’s volume. All of these might be added in later versions of RetroArch though.