Share your experience!
sometimes the videos hang and take a long time to play and afterthat the sound of the keypress has disappeared for seconds.
Are you playing the videos recorded with the device?
yes and the same thing with the other videos.
Can you try settings-apps-all-album,force stop and clear data.Restart.
i have done this before ...and i made a full repair with pc companion today , and waiting for the results.
See how it is after the software repair.
the problem is not gone after the software repair 
I am sorry,have your device checked at a sony service.