Starview, sound not in synch?

Apologies if this has been asked, I have tried a search. Picture and sound, usually on movies do not quite synchronise, any ideas?. I have tried messing with the audio button on keypad.
Thanks
Steve

 

I beleive Ive read somewhere that a full factory reset fixes this problem,

Cheers

 

Thanks
Somebody mentioned changing to RGB, but makes worse, if I do reset, will I lose my favourite line ups?
Steve

 

yes