As of Chromium version 71, the autoplay is disabled by default unless player interacts the screen
but there is no way to interacts the screen.
And the possible way to fix it is
change the #autoplay-policy in Chromium's flags to "No user gesture is required.".
As of Chromium version 71, the autoplay is disabled by default unless player interacts the screen but there is no way to interacts the screen. And the possible way to fix it is change the #autoplay-policy in Chromium's flags to "No user gesture is required.".
Autoplay Policy Changes source: https://developers.google.com/web/updates/2017/09/autoplay-policy-changes
Edit: just notice it is garry mod issue not the cinema issue