How to allow video autoplay in a Google Chrome kiosk app in version 66 or later

This function is often useful on kiosks, where you want to autoplay sound from one specified site. In that case, you can just to to:

1. Settings
2. Advanced
3. Privacy and Security
4. Site Settings
5. Sound

And enable autoplay for particular website. It should override its default behaviour and play the sound immediately after displaying site.

For a kiosk, I added this site to chrome://settings/content/sound

file:///*

This allowed videos with autoplay to have sound for local files.

It turns out that the end user will have to enable automatic video playback manually, by:

1. upon startup pressing Ctrl+Alt+S
2. logging in
3. opening a Chrome browser and typing: chrome://flags/#autoplay-policy
4. changing the "Autoplay policy" from "Default" to "No user gesture is required"
5. pressing "relaunch"
6. rebooting the device

From now on autoplay works again in webview components used in your app.

See this comment thread about this topic by Google.