Here’s a tip if you’re showing people your work using QuickTime Player: You can control playback using the J, K and L keys.

L – Play forward
LL – Play forward at double speed
LLL – Play forward faster
K – Pause
J – Play backwards
JJ – Play backwards at double speed
JJJ – Play backwards faster
K and L – Step foward one frame
K and J – Step backward one frame

The player is pretty good at playing the soundtrack at the same pitch even when playing the visuals quickly. These shortcuts work when presenting movies in full-screen mode. If the controller pops up, you can drag it off the edge of the screen or to another monitor.