The web video revolution has changed and minimized the role of music in truly effective video.
I'm not talking about explainers or sales video where someone narrates the words they're seeing on the screen.... that's a barely passable powerpoint. I'm talking about short but content-rich videos that make a point, persuade, or motivate-- in any setting, from the web to an arena in Las Vegas.
There are many sources of music. I'm not a lawyer, but if you're tribute is being seen just by family and friends and you produce it yourself, you can use whatever you want (I think). If you are a producer who makes money at this game, and you're showing your project in a public setting, you have to stick to music that's cleared. That is, that you have the right to use. That music can come from a music library (they have existed since the dawn of television to provide enough music to quickly score thirty or sixty minutes of what were then 33 episode seasons).
Music libraries became the friend of the industrial film, slideshow, and video producers from the 50's til today for much the same reason.
Good mediamakers know that music is more than filler. It is the blueprint for edit of the material you have gathered, and the main component of driving the audience's feelings, which in turn drive their buy-in of whatever you're selling.
But the music can be original as well, and the computer revolution of the 90's (firewire, usb, and other ways to import (or digitize sight and sound into the computer for editing) really open the floodgates of competent and sometimes brilliant composer / producers who know how to make emotions shift on cue.
When I entered the business it was in synchronized slideshows-- two slide projectors and a tape deck playing the sound with a control track to tell the projectors when to dissolve and change to the next slide). I noticed right away that other slide show producers tended to ignore the soundtrack. Maybe they didn't go to the movies much. What they tended to do was simply take one piece of music and loop it over and over no matter what the length of their show-- 5 minutes or 20 minutes. This will drive an audience batty. Also, it provides no signposts on how you should feel during the telling of the "story". So we first stole music from soundtrack albums to build the soundtrack, so we could trot when we had to and gallop toward our conclusion. Then we discovered music libraries and it was off to the races for the next 40 years.
But lazy loopiness came back in the nineties when "Flash", a media synchronizing tool for digital files, was introduced. It used compressed digital visual files, usually vector-based and sound, and compressed into a small file that could play on the 1200 baud modems and underpowered computers of the time.
You could do all kinds of cool video things with Flash, but not so much with the music. Flash begged you to take one music file and loop it, since it could only sloppily sync to one audio file. This eliminated longer shows (which actually was ok for the web at that time). But it made people lazy again when it came to sound.
But today there's no excuse. The web is fast, baud rates are incredible (comparatively), and the sources of music are plentiful, with new upstarts getting into the library or original composition game daily. The only thing keeping today's producers from thinking like motion picture scorers are the use of "beatz", music loops that can introduce monotony and predictability into the equation, unless you're careful, creative, and prolific (composing with more than one "beat".
So in you're next video, the soundtrack should reflect the history, challenge, innovations, wonderful inspired people, impact on people , and triumphs of your company or your Uncle Bob. No matter what the subject, the underlying proof of the premise is in the emotions you inspire. Your client or family will thank you.