Gradually Change the Playback Speed in QuickTime With Option + Click
QuickTime is a surprisingly versatile little video player included with OS X, but the most recent version is missing some features that were a little more obvious before. In this case, Mac Issues indicates that you can Option + click the advance arrows to get a little more precision.
You usually press the fast forward or rewind buttons, QuickTime switches between 1x, 10x, and so on. However, if you hold down the Option key while pressing, you have much more control over the speed. You can set it to about 1.2x or 1.8x, or whatever you like. It’s a small thing, but if you’re watching a video and want more precision, this is a handy little trick. It’s also further proof that it’s worth pressing Option + Clicking Everything in OS X to see what’s in there .
How to Change the Playback Speed of a Video in QuickTime X | MacIssues