Inception: Did the soundtrack hid subtle clues as to what was really going on?

In recent days a video by a pseudonymous author, camiam321, comparing the Edith Piaf song Non, je ne regrette rien to Hans Zimmer's score for the movie, has been widely circulated on the web. The video plays a musical cue from the Inception score - two ominous blares from a brass section - followed by a slowed-down version of the Piaf song (which the Inception characters play at regular speed as a warning to wake up from a dream state). They sound nearly identical.

Zimmer, a film composer and producer who won an Academy Award for his music for The Lion King and was nominated for Rain Man and Gladiator, says the sonic similarity was not only intentional but that it was also an element of an enigmatic film "that wasn't supposed to be a secret".

"I've seen it!" he says of the video. "I was surprised how long it took them to figure it out." The musical cue, Zimmer says, "was our big signpost" to show the film's characters moving from one level of dreaming (or reality) into another. "It was like a drawing of a huge finger saying, 'OK, different time.'"

Zimmer says the idea for this musical game began with Nolan, the film's director and writer. "He had the Edith Piaf always written in the script, the 'da-da, da-da",' Zimmer says, imitating the cadence of that song. "It was like huge foghorns over a city, and afterward you would maybe figure out that they were related."

In the liner notes to the Inception score, Nolan writes that the music is meant to pull the audience "through a potentially confusing tale by orienting them emotionally, geographically, temporally". He also describes Zimmer as someone who "never lets practical realities limit his belief in the power of ideas".

Technically, Zimmer says, that portion of his score is not a slowing-down of Non, je ne regrette rien (written by Charles Dumont and by Michel Vaucaire), but is constructed from a single manipulated beat from the version recorded by Piaf in 1960.

"I had to go and extract these two notes out of a recording," Zimmer says. "I love technology, so it was a lot of fun for me to go and get the original master out of the French national archives. And then find some crazy scientist in France who would actually go and take that one cell out of the DNA."

Zimmer says the remaining portions of vocals and "isolated brass stabs" were then rerecorded with the film's sound designer, Richard King, on the Warner Brothers lot in Burbank, California. The manipulated beat comprises about five minutes of Zimmer's 132-minute score, but all of its tempos, he says, are "subdivisions and multiplications of the tempo of the Edith Piaf track".

"I could slip into half-time," he says. "I could slip into a third of a time. Anything could go anywhere. At any moment I could drop into a different level of time."

In this sense the score is Zimmer's personal interpretation of Inception, which many viewers see as a commentary on the nebulous boundary between dreaming and reality. "Everybody thinks the dream is the important part," Zimmer says. "For me the time was the important part: the idea that, in a peculiar way, Chris had made a time-travel movie that actually worked."

In 2008 Zimmer was briefly excluded from an Oscar nomination for the score to The Dark Knight, which was deemed to have had too many composers. (The Academy of Motion Picture Arts and Sciences eventually reversed itself and allowed him and a co-composer, James Newton Howard, to compete for the award.) Zimmer says he had no idea how awards bodies would react to his Inception score's incorporation of the Piaf track. "I didn't use the song," Zimmer says. "I only used one note. But look, I couldn't care less about awards. I know I'm not supposed to say this. But when you work with Chris Nolan, when you work on a movie like Inception, it's for the adventure."

l Inception is in cinemas now. Confused by the ending? Visit www.inceptionending.com to read various theories about what the film means.