There's a movie on YouTube with some mechanical music shots.
"Roxy Hart" (1942) has a player piano playing at time 3:30,
a quiet piano at 10:35 and a piano playing out of sight at 18:05.
Here's the link:

https://www.youtube.com/watch?v=vARONvZafns 
Roxie Hart (1942) Classic Film, Ginger Rogers, Adolphe Menjou
& George Montgomery

Lee Rothrock
Springfield, Oregon