Yes. The video linked in the original post is titled inaccurately, it doesn’t contain “Sun is reddest, Chairman Mao is dearest” (which is the music you linked).
The songs in the video are (English names might be inaccurate, I don’t know Chinese):
0:00 天上的太阳红彤彤 / Red sun in the sky
0:54 红太阳照边疆 / 붉은 태양 변강 비추네 / The red sun illuminates the frontier (it’s a song written by Yanbian Koreans, with lyrics in both Korean and Chinese)
1-hr-version, same title, but somehow different tune? https://yewtu.be/watch?v=IsQIi-bJOV8
Yes. The video linked in the original post is titled inaccurately, it doesn’t contain “Sun is reddest, Chairman Mao is dearest” (which is the music you linked).
The songs in the video are (English names might be inaccurate, I don’t know Chinese):