having ps3 video audio problem

[Lt. Aldo Raine]

was going to post this in ps3 and games but i think it will get more feedback here..

with my ps3, when watching a blu ray or playing a game or, even when its in the menu sometimes, the video and audio jump out for a sec(the screen goes black and the audio cuts off jus for a sec), this only happens once everytime i turn it on, and its happened a couple times if i change the movie, sometimes it happens 5mins in and sometimes 45mins in.
i have a 40gb ps3
and i have a sony str dg720
, i noticed this happeneding after i got the reciever, but i took it back twice and it still happens, when i had my old receiver i had hdmi for video straight to my tv and optical for audio to my receiver and i never had this problem before, do u think it could be the ps3s problem, maybe having trouble sending both audio and video through hdmi, i got all new hdmi cables so i dont think thats the problem, its really annoying becausing i can be watching a movie and be really into it and then it just cuts out for a sec and throws me off,
so help me out let me know what u think the problem is,
if i have left anything out then feel free to ask