Now after Gandalf had ridden for some time the light of day grew in the sky, and Pippin roused himself and looked up...Even as Pippin gazed in wonder the walls passed from looming grey to white, blushing faintly in the dawn; and suddenly the sun climbed over the eastern shadow and sent forth a shaft that smote the face of the City. Then Pippin cried aloud, for the Tower of Ecthelion, standing high within the topmost walls’ shone out against the sky, glimmering like a spike of pearl and silver, tall and fair and shapely, and its pinnacle glittered as if it were wrought of crystals; and white banners broke and fluttered from the battlements in the morning breeze’ and high and far he heard a clear ringing as of silver trumpets.
Paragraph two above is pretty-near the same lines that Boromir speaks when he is talking with Aragorn in Lothlorien. It at least looks like the inspiration for that sequence.
I love the fact that you can keep finding new details in the relationship between the movie and the book--it seems you could dig into this stuff forever and never reach the end of it.