Depends on the length of the instrumental, really, along with the type, placement, and the amount of footage I have left. For instance, a thirty second instrumental at the end of, say, an already three minutes long romance video, I'd go back, pick out some of my personal favorite scenes, then make them kind of a "memories" reel, make them black and white, synch them to the music and mood.
As for metal solo's, that's hard to say. The last time I ended up on one of those, I had to cut it back, because I was out of good footage. It really ended up killing the video for a lot of my viewers, but that's my fault for shortening a metal classic (The Unforgiven by Metallica).
Had I continued on, I probably would have synched to the flow and feel of the solo.
I need to make a new instrumental video, try to get it right this time.








