First music is there's a drum beat at the first 5 or 10 seconds of Snow's execution (if I'm not mistaken). While the drums are being played, Katniss walks slowly on the aisle.
Second is when Katniss stopped walking, the drums stopped too. Alma Coin gave her speech to Katniss. And the part when Katniss reaches her hands to her arrows, a music played. It's more like a voice of a girl? The voice of the girl can still be heard until Katniss shot her arrow to Coin.