The charts are pictures of the sound spectrum in a movie over a certain time period. The person making the graph "records" the sound during playback of part of the movie. The numbers on the top indicate the frequency of the sound recorded, and the colours represent the level of the sound (in increasing order, blue, green, yellow, orange, red, pink, magenta. maroon, purple). The graphs are presented with the start of the recording period at the bottom of the graph, and the end of the recording at the top.
These are often used to show at what frequency the bass sounds in a soundtrack occur. For example, if a portion of a movie has a pink blob at 20 Hz on the graph, that indicates that there is a very loud 20 Hz component to the sound during that part of the movie, and that a reasonably good subwoofer is required to be able to play that back.