As this person enters the scene, what is true about P-frames?

As a person enters the scene, P-frames (Predictive frames) increase in size. P-frames contain only the changes in the image from the previous frame (I-frame or another P-frame). When there is movement or new objects enter the scene, more data is needed to describe the changes, resulting in larger P-frames. References: Axis Communications documentation on video compression and frame types in H.264.