I have yet to find a single case, ever, that I would think that autoplaying video and/or audio on a website is appropriate. It is just plain, 100% annoying and presumptuous. Offer a NON ANIMATED option to play something and give the user a choice.
Besides being extremely annoying, unwanted video consumes TONS of bandwidth, CPU, and battery on devices.
The web is turning into TV- something for sites to FORCE what they want you to see, they way they want you to see it. Want to use a smaller window for your browser? Well too F'ing bad! Want a nice menu at the top so you can jump to the info you want? Well too F'ing bad! Want to read something without things jumping in front of you over and over? Well too F'ing bad- "we want your feedback" "subscribe!" "take our survey" "click here to chat!!" Want to know how big a page is? Well too F'ing bad- it scrolls forever, adding more and more without warning? Want to just see some actual content? Well too F'ing bad- you have to wade through multi megapixel useless images, sectionalized areas, side scrolling, junk with tons of while space. Want to try and read something without distraction? Well too F'ing bad- every single site has to have animated junk all over it, constantly moving and scrolling. Want to click on something and have instant action because your time is important? Well too F'ing bad- we are going to make EVERYTHING fade in and fade out, scroll in and scroll out. Ug!!!!!!!!!!
Sorry, this stuff touched a nerve. A big one.