• Adobe After Effects Expressions

  BPM display

  Posted by Rahim Kanji on June 20, 2012 at 3:12 am

  Hello, I’m very new to expressions to forgive my ignorance..

  I’m looking to add a BPM count on a project, based on a 4-minute audiotrack. I’ve got an expression for a timecount, but not for BPM. Thanks ya.

  -RK

  Rahim Kanji replied 14 years, 2 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Kevin Camp

  June 20, 2012 at 5:31 pm

  if bpm is beats per minute and you are trying to measure the number of beats per minute in an audio layer, then you could try dan ebberts’s beat counter expression here:

  https://www.motionscript.com/design-guide/audio-count.html

  you’d first convert the audio to keyframes (animation>keyframe assistant>convert audio to keyframes), then create a text layer and put the expression on the source text property of the text layer.

  you’ll need to tweak the threshold variable to work with the beat levels of you audio track, but once you’ve done that, the expression should count the beats as they happen.

  once you have it counting correctly, you could easily modify the last line of the expression to something like this”

  n * 60 / time // number of beats X number of seconds in minute / time in seconds

  to get beats per minute.

  that calculation is updated every frame, if you wanted to decrease the update interval, this would update just once per second:

  n * 60 / Math.round(time)

  Kevin Camp
  Senior Designer
  KCPQ, KMYQ & KRCW
• 

  Rahim Kanji

  June 21, 2012 at 5:14 am

  Thank you very much!

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