Facebook said that there are still a few countries where the Facebook Messenger video calling wont work because of improvements needed in video quality. Facebook also said that the video calling would work well even with users who are not connected over Wi-Fi. With this rollout, Facebook hopes to take on the entrenched players in video calling arena like Viber and Skype and etch out market share for itself. Facebook has been giving Facebook Messenger quite a makeover in recent months. Facebook Messenger has already logged in almost 600 active users and still going strong. According the users the video calling over Facebook Messenger is pretty decent with basic chatting. Facebook is looking to add more features to the video calling and turn it into a full fledged standalone platform. Facebook Messenger Video Calling is now available on iOS and Android.