If you are watching videos using the QuickTime Player, you can increase the speed by clicking the double forward arrow button in the controls. Click once for 2X, again for 4x, again for 8x. You can also use the keyboard shortcut Command+Right Arrow. Use Command+Option+Right Arrow to increase the speed by 0.1x. Use the double rewind arrow button or Command+Left Arrow to play the video in reverse.
Mac Video Tutorials and Tips for Apple Users
