For piano Realtracks I think it all depends on when and where it was recorded. I'm certain we've used Disklavier pianos on many of them, which is an acoustic grand piano with MIDI capabilities so they would've recorded both MIDI and Audio at the same time, but not all piano RT's of course.

For other instruments, it's a mixed bag. Drums are not hard as you can either use drum triggers or run the multitrack audio through some sort of trigger software, both of which will generate some MIDI, though it's not perfect. Other instruments usually have to be done manually, with the possible exception of guitar and bass as I know there are MIDI pickups available for those, just not certain if we've used those in the past.

Tldr: Not every RT has notation, and it's not always 100% accurate as it's intended for visual notation use not for MIDI/audio use.

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