download YouTube video to PC (windows 10), then transfer to iphone. Play the video in iphone. Either playing in the app, or the video playing at background, video will start from the beginning if the network is changed (for example, when I leave my house, network will change from WiFi to 3G network)

Televzr player 2.0.7 for iPhone 

I meant, iPhone is switching networks. For example, from 3G to WiFi, from WiFi to 3G etc., video playing will interrupt and start from the beginning.