• Adobe After Effects Expressions

  adding audio keyframes to a value over time, without ever decreasing over time

  Posted by Robert Dupper on December 8, 2011 at 11:11 pm

  After 4 hours, i give up.

  I have a ‘flow’ property going smootly from 0 – 1000 over time.
  I would like to add audio keyframe values to this value, in such a way that they only add to the value of the ‘flow’ property, and that the flow value never decreases over time.

  i was looking into retrieving data from a previous frame, but i could not figure it out : (

  thank you for any help.

  robert.

  robert dupper

  sony vegas
  after effects
  photoshop
  logic

  Robert Dupper replied 14 years, 5 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  December 8, 2011 at 11:27 pm

  You pretty much have two choices. The easiest is to get the Sound Keys plugin, which has a Falloff Range setting of (None), which will integrate the value (it will keep going up).

  The other option is to do it with an expression that loops through each previous frame, and adds up all the previous audio values. The big drawback with this method is that the calculation takes longer at each successive frame, so things can slow down if your comp is very long.

  Dan
• 

  Robert Dupper

  December 9, 2011 at 7:00 am

  Dan,

  this is not the first time you saved my life : )

  The last thing i did yesterday night, is post this question.
  The first thing i saw this morning, was your reply.

  Thank you so much for your online presence.

  Rob.

  robert dupper

  sony vegas
  after effects
  photoshop
  logic

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