I have been experiencing this problem for the last few days. I've tried going in to settings and changing things on the sound menu but to no avail. I can get no sound on my videos, Internet videos and I can't change the volume setting when the phone is on the home page.
I originally thought it might be a problem with the volume buttons on the side of the phone but they work for voice memo sounds. That audio seems to come from the ear piece so I wonder is there a problem with the speakers on the bottom of the phone.
Any ideas on what's wrong? Did I possibly change some settings without realising? Is there a menu to change volume settings for videos?
I'm going I go into an apple shop when I'm near one because this is driving me crazy!