Sound and picture are out of sync - sound is played before the picture.
With modern flat TVs, audio and video signals are sent along an HDMI lead in a digital format.
Video information takes longer to process than audio information, because of this you will hear the audio will arrive before you see the picture( know as ' out of sync' ). HD video requires even more time to process because of the large amount of data, therefore the 'out of sync sound' will greater on HD than SD.
To compensate for this potential delay, the AV Sync function has been implemented on all video inputs ( adjustable via the setup menu). This function allows to manually adjust the delay between sound and image (if required).