Is it possible to read the pitch of a currently playing sound?

If so, how?
If not, [Feature Request] =)


You would be able to with an external library. Google some C++ solutions

I have been looking alot at PortAudio as a possible solution. Do you have any that you would recommend?

If you mean analysing the sound, this might be hard to do in real-time - the engine does not provide a way to retrieve the audio stream, so whatever you use will have to be offline on your sound assets. Sonic Visualiser is a good (and free) start.
At the moment the best you can do is retrieve the mic input and analyse this one before handing it over to the engine.

The other solution is to capture the audio mix sent to the audio device, analyse it in an external software and get the figures back to the game through network or something else.

I was actually looking more for a cpp library/solution that I could use in developing a plugin that I could read the pitch from as a value in game. The idea is to be able to work it into a sort of value recognition game similar to singing in Rockband.

Yeah, I understand - you might want to have a look at aubio.

But be aware that accessing the audio stream from anything else than the mic input is really hard (to say the least) given the current UE4 audio implementation.