As I mentioned earlier, the two, fanfare and theme song are not mutually exclusive. The Superman theme would be, I think a theme song that begins, opens, with a fanfare. On your video, the fanfare ends at about 1:15. It begins the theme, but it is not separate from it. It part of the whole. Music is made of pieces that come together to form a whole. Some musical terms can be very vague. Some types of music are more narrowly defined. I am not an expert on music theory or music history, so I was trying to find some list of characteristics that make something a fanfare, other than just saying “you’ll know it when you hear it” or “if John Williams wrote it, there’s going to be a fanfare in there somewhere” and these apparently are some of the characteristics of a fanfare (Source):
Volume
Fanfares are nearly always played fortissimo, or loud. Since the objective of the music is to command attention, volume and power are important factors. Historically, fanfares were played at hunts and coronation ceremonies before hundreds or thousands of spectators. In the days before electric amplification of sound, the music had to be loud enough to cut through the audience noise and announce the event was about to begin.
Orchestration
The lead melody line in a fanfare is carried by the brass, particularly trumpets, coronets and bugles. The trombone, tuba and French horn are also employed heavily to accentuate the rhythm. Some fanfares may feature a solo passage played by one of these lower-range brass instruments for effect. Drums and percussion are meant to keep the tempo moving steadily forward, such as in military marches where the cadence is set for a fast-paced walk.
Features
Fanfares contrast passages using the harmonic series, usually in the lower register, with stepwise movement, usually in the higher register. They are usually played in major scales. The strong rhythmic character of a fanfare often employs repeated rhythms -semi-quavers, dotted rhythms and triplets – and repeated notes at the same pitch. Imitative, contrapuntal textures are contrasted with rhythmic chordal passages.
Don’t ask me what “Imitative, contrapuntal textures are contrasted with rhythmic chordal passages” means, because I don’t know. :-)
One of my favorite modern composers is Aaron Copeland and one of my favorite of his compositions is a fanfare and one that is a basically a complete, self contained composition in and of itself.
Fanfare for the Common Man
You listen to enough of these, you will know exactly what a fanfare is. A theme song is simply a song or any piece of music associated with a particular tv show or movie or even a person. It’s a relatively modern term and can really be any kind of music at all, it just needs to be associated with those particular things.
I’m done. I may even be right, there’s always a chance. :-)