• Adobe After Effects Expressions

  Volume relative to distance from camera expression

  Posted by Jesse Stormer on June 10, 2012 at 9:24 pm

  I have videos passing by my camera with sound on them, and I’d like the audio to get louder/quieter relative to their distance to the camera. I tried modifying an ‘opacity relative to camera distance’ expression to fit audio levels, but to no avail. Can anyone help me out with this one?

  Dan Ebberts replied 14 years, 1 month ago 2 Members · 1 Reply
• 1 Reply

• 

  Dan Ebberts

  June 11, 2012 at 4:02 pm

  To get this to work, you need to pick a nominal distance from the camera where the audio will be at normal (0 db) volume. When the layer is twice as far from the camera the audio will be 6 db down, 12 db for 4 times as far, etc. I have it set up for a nominal distance of 500 pixels:

  C = thisComp.layer(“Camera 1”);
  nominal = 500; // distance where sound level normal
  d = length(C.toWorld([0,0,0]),toWorld(anchorPoint));
  offset = -20*Math.log(d/nominal)/Math.LN10;
  value + [offset,offset]

  Dan

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