1. Twitter. Go to https://twitter.com/settings/account click on Data Usage and then click on Autoplay and select Never.
2. Instagram, does not allow turning off videos as far as I know. Browser hack below, might work. Might...
3. Facebook. Go to the drop down menu at top of page. Select Setting and Privacy > Settings. Look for Videos in that option and there should be a toggle to turn of Autoplay.
4. To turn off Autoplay for all websites with ads, news features, etc. (CNN, etc...)
Create a new browser shortcut on your desktop to start Google Chrome.
1. Create a new shortcut
Right-click your desktop and choose New > Shortcut.
2. Browse to Chromes .exe-file
In the next screen, click the Browse
button and find Chromes exe. It should be in C rogram Files (x86)GoogleChromeApplicationchrome.exe. Select it and press OK. Do not press Next yet.
3. Add the disable autoplay-argument
Next to the file location under Type the location of the item, add --autoplay-policy=user-required. Make sure its after the quotes and press Next.
4. Name the shortcut
Call the shortcut whatever works for you, but make sure you can differentiate it from the normal Chrome. Call it, Chrome (no autoplay), but you could also name it Chrome disable autoplay, video blocker Chrome, or anything else. Once youre done, press Finish.
5. Launch Chrome using the new shortcut. Go to a website that has autoplay to check it out and verify that it works.