Can not seek/fast forward when playing video from ipad

I use Airplayer on iPad to play video on my PC(with Tversity free installed). I can play most video perfectly, but I just can not use the seek bar when trying navigate on the video. There there anything wrong? should I buy the pro version? please give me some advice.

Transcoded video can’t normally be navigated due to not having all the timestamps required. Only after it’s finished and the video watched again would the saved version be used with all the features usually available then.

Although, I thought TVersity playing to an iPad kinda required the Pro version. How do you play it now?..