How to Do a Quicktime Screen Capture With Audio

First you have to install soundflower plugin	https://drive.google.com/open?id=1xU1uD2JmuYHLgjkB0P9jWDF7mImQr8IX
After the Install go to >Apple System Preferences
Click On Sound
Choose Output Soundflower 2Ch.
Open QuickTime Player
Click on >File>New Screen Recording
click on the down arrow icon next to the recording icon and choose Soundflower (2Ch)
Find the web content you want to record youtube or vimeo or etc Pause the video where you want to start recording Click on the RED record button on Quicktime Player

Drag the box around the web video window you want to capture and then Click on the Start Recording Icon
click in the top tool bar on the mac window and click on the "Stop" icon
You will have the freshly recorded quicktime but to hear it on the mac you have to change the sound output back.
Then go to >Apple System Preferences
Change the output back to Internal Speakers or Headphones You should be able to hear the audio off the quicktime now.
Finally you will be able to save the video to use as a quicktime.