mali yung connection mo please double check. Wag kanang mag gamit ng mysql, use PDO or simpling mysqli.
check link below :
http://www.w3schools.com/php/func_mysqli_connect.asp
http://www.w3schools.com/php/php_ref_mysqli.asp
try mo ang WebRTC at Twilio search mo lang paano gamitin, pero ang hirap gamitin sa php codes maganda pag mag node.js ka bro.
check link below may sample nayan:
https://www.sitepoint.com/webrtc-video-chat-application-peerjs/