Almarg, I would have bet good money it was one of Schubert's chamber works. Fortunately, it didn't take long to scan through his 2 trios, and once I ruled out LvB, Brahms was my next stop. I listen to the Schubert, LvB, and Brahms piano trios the most, and that piece was so familiar it had to be one of those three.
I have to say I prefer the Floristan Trio account to the youtube version.