And, before we had even embarked on The World’s End, we started putting a version together by segueing the songs, a little like a DJ mix, with overlapping starts and ends, and we would bridge them with sound effects. So we were tinkering with that for a while.
The next big step was a table read he did in early March 2012. He had mics around the room and recorded a sound file, which he sent over to me. Over the next couple of months in my spare time, I put this together — we took the table read, the songs and the sound effects, and added extra sound effects and put together, effectively, a 100-minute radio play that was the film without the pictures. We could give that to potential producers and other executives and say, here’s the film. You can hear it. Now we need to put the pictures on top of it. It was a unique way to sell the film to the studio — we had something tangible. People could put headphones on and become enveloped in the world of Baby Driver before we actually shot a frame.
yea, gareth edwards, yea
and this amount of from-scratch creativity was done specifically just to pitch the film to the studio
(the whole interview is worth reading in terms of the specificity of the editing, which was done on the set while shooting)