Stop autoplay videos in Safari on Mac
Some websites — and others who provide those sites with content, including advertisers — automatically play video when you visit their site. Muting tabs and windows is a quick and temporary solution, but you can permanently block video for an individual website or for all websites.
Block video for the currently displayed website
In the Safari app
on your Mac, click 
in the Smart Search field, then choose Website Settings.Hold the pointer to the right of Auto-Play, then click the pop-up menu and choose an option:
Allow All Auto-Play: Lets videos on this website play automatically.
Stop Media with Sound: Blocks autoplay for videos that contain audio, but allows other videos to play.
Never Auto-Play: Blocks autoplay for all videos on this website.
Block video for all websites
In the Safari app
on your Mac, choose Safari > Settings, then click Websites.Click Auto-Play in the list on the left.
Do any of the following:
Choose settings for a website in the list: Select the website, then choose the option you want for it.
Choose settings for all websites that aren’t currently customised: Click the “When visiting other websites” pop-up menu, then choose an option.
You can see websites you’ve customised below Configured Websites. If you don’t see Configured Websites, either you haven’t customised a website yet or you’ve cleared the list.
Choose settings for all websites: Make sure no websites are listed below Configured Websites (to clear the list quickly, select the websites, then click Remove). Click the “When visiting other websites” pop-up menu, then choose an option.