It was an animated music video. The animation was very top-notch and when compared to American cartoons seemed like it was made in the 70s maybe, but the text on Youtube was entirely in Russian so I could not tell you.
It opened on a golden double headed eagle, but quickly transitioned to a cavalry unit. If I remember correctly it seemed to depict WW1 cavalry unit fighting against Germany. It ended with a cavalry charge pushing an army off a cliff.
It's a video someone made to the song commonly known as "White Army, Black Baron".
The song, which is really titled "The Red Army is the strongest" (which sounds rather mundane in its English translation) was written by Pavel Grigorevich Gorinshtejn and composed by Samuil Pokrass, the latter of which later emigrated to the US and is most famous for his musical version of The Three Musketeers.
The song was composed during the Civil War of the early 1920s and was meant as an anthem for the Red Army. It details the efforts of the Red Army defeating the White Army and the so-called Black Baron, which was the commonly known nickname of Baron Pyotr Nikolayevich Wrangel or Peter Wrangel by his German name (his family came from German aristocrats in the Baltics). Wrangel was a commander in the Tsarist army and alter in the White Russian army, which he lead with some success against the Bolsheviks in the Civil War. Later he was forced to flee Russia and died in 1928 in Belgium.
The sung gained a lot of popularity and was later sung in the Spanish Civil War as well as being adapted by the Austrian socialist in their own version called "The Workers of Vienna".
As for the video you are talking about, it was not some sort of official Soviet propaganda video but rather something a user made with different footage from Soviet cartoons. Unfortunately so far I have been unable to find the source material but I am as you looking for the specific cartoons used which seem to be some sort of animated stuff about the civil war...
Edite: Found the video. Maybe someonelse can identify the footage.
Further update:
Some of the footage comes from the Soyuzmutfilm "Eaglet" (Orlenok, Орлёнок) from 1968. The other footage I am still working on.