As of version 66 of Google Chrome onwards it will no longer automatically start playback of audio and video files when the playback volume is not muted.
This change was made to prevent autoplay on add-videos and other annoying web page elements. However, this has negative consequences for a number of perfectly valid applications of the autoplay feature, for instance in signage applications.
The new default behaviour of not auto playing a video with sound can be overridden at the startup of the Google Chrome browser with the command line options
The new default autoplay behaviour is also present in the Chrome browser on ChromeOS (currently in the beta channel). For Kiosk-apps running on ChromeOS there are no command line options, only configuration using the Manifest.json file.
Currently there is no option in the documentation of the Manifest.json format that allows changing the autoplay policy.
Is there a non documented way or a way outside the Manifest.json to change the new Chrome default autoplay policy in Kiosk apps?