This is a 1951 Russian animation of an 1833 fairytale poem written by Alexander Pushkin that is based upon the classic Grimms tale, Snow White and the Seven Dwarfs. It was directed by Ivan Pyetrovich Ivanov-Vano, known as the ‘patriarch of Soviet animation.’
You can read Pushkin’s The Tale of the Dead Princess and the Seven Knights.
The film is in Russian so you can use the YouTube settings to turn on English subtitles.