As per the manual, found on the Samsung web site, page 206:
"You can watch a program whose signal
has passed through the TV’s tuner and
watch video from one external video
For example, if you have a cable box
connected to the Cable In jack, you can
use PIP to watch programs from the
cable box and a movie from a Blu-ray
player attached to the HDMI In jack.
NNWhile Smart Hub or Program Rating
Lock is on, you cannot use PIP.
You can choose to listen to the sound
from the main picture or the sub
The picture from the
external video source will be in the
main screen and the picture from
the TV’s tuner will be in the PIP subpicture
––Main picture: Component, HDMI
–– Sub picture: TV"