OK, this one’s a bit of a cheat as you can’t find the whole short on YouTube, however, two separate official channels have uploaded both halves of this famous cartoon, so it I think it counts.
The Cat Concerto (1947)
https://www.youtube.com/watch?v=QpEfHVFilRc - Part 1 from the WB Kids YouTube channel (5 mins long)
https://www.youtube.com/watch?v=CtLpv6huG3A - Part 2 from the Boomerang Official YouTube channel (2 mins long).
Synopsis:
Tom Cat is a concert pianist who plays beautifully until he is interrupted by Jerry Mouse.
Directed by Joseph Barbera & William Hanna.
Trivia:
• Following its release, it was met with critical acclaim, and is considered one of the best Tom and Jerry cartoons. It won the 1946 Oscar for Best Short Subject: Cartoons.
• The same year MGM produced The Cat Concerto, Warner Bros. released a very similar Bugs Bunny cartoon called Rhapsody Rabbit, directed by Friz Freleng, with Bugs against an unnamed mouse. Both shorts used near identical gags, the same piece by Franz Liszt, and had similar endings. Both MGM and Warner Bros. accused each other of plagiarism, after both films were submitted for the 1947 Academy Awards ceremony. Technicolor was accused of sending a print of either cartoon to the competing studio, which then allegedly plagiarized their rival’s work. This remains uncertain even today.