Ali G and the Magic Tempo

9th October 2019

For this IVCA award-winning promo, we needed a tempo that made it dead easy to cut…

Magic Tempo

For this piece, composed for Paramount, we decided that the pace of the music had to drive the cut.

Because the cuts literally are the samples I found for the music, we found a tempo at which each beat takes a perfect, whole number of frames.

The formula

We knew we were needed raucous party music, so it wasn’t a problem to keep to a 4/4 time signature. In 4/4, there’s 4 beats to the bar – and apart from drum rolls and trap high-hats, each beat’s divided into 4 sixteenth notes (semiquavers).

There’s a formula I figured out years ago, to work out timings for echoes that match the music:

The length of each sixteenth note, in seconds, is the same as 15 divided by the BPM of the music.

Now, if there’s 25 frames per second in the video, that must mean there’s tempos where each musical sixteenth tick takes exactly as long as… some whole number of frames.

Here’s those tempos:

  • 6 frames last exactly 1 sixteenth note at… 62.5BPM (slow dub/reggae)
  • 5 frames last exactly 1 sixteenth note at… 75BPM (slow ballad, slow hip-hop?)
  • 4 frames last exactly 1 sixteenth note at… 93.75BPM (hip hop)
  • 3 frames: 125BPM (house / techno / pop) – that’s the tempo of the Ali G music here
  • 2 frames: 187.5BPM (fast rock / crazy hardcore bass music)

What that means is, you can line your 125BPM music up and cut to it, and if you cut in multiples of 3 frames, your cuts are cast-iron guaranteed to fall on a beat.

I know hardly anyone cuts as fast as every 3 or 4 frames… which means that, if you cut only as fast as eighth notes (quavers, half-beats) then 150BPM becomes another magic tempo… you just need to cut in multiples of 10 frames.

The result

The producers weren’t entirely sure the concept was going to work, but when they got the first version of the music they were laughing (in a good way, I think). It was also much easier to get a clean, precise edit at speed – and the spot did really well for them.

Live Fast Die Old

I used the same trick with The Gate Films on their film Live Fast Die Old – their footage was intense but the action wasn’t super high-speed; and they wanted music with plenty of rhythmic noise to cut to. I’ve got a feeling this one’s at 93.75BPM, which is the magic speed for 4-frame cuts. The production company started fielding calls from Shazam, due to viewers trying to work out what the music was…