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CharlesBandla
CharlesBandla
Participant
August 1, 2026
Question

Request for help with a script

  • August 1, 2026
  • 2 replies
  • 25 views

I’m working on a Visual Music film that uses Audio Amplitude layer keyframes created through Audio Layer > Keyframe Assistant > Convert Audio to Keyframes. The result is one linear keyframe per frame (@ 24 fps). Because its desired to act as a switch to turn on/off I’ve converted all the keyframes to hold keyframes.

These key frames will be used to turn the opacity of a shape layer on and off to synchronize graphics to audio. The desired value of the keyframes should be restricted to 0 (off) or 100 (on). Keyframes of any value of other than 0 or 100 are to be deleted.

I worked up an algorithm by hand processing the keyframes. But since there are over 1000 keyframes to be processed I’d like to automate the process with a script. An elaborate interface is not necessary, the goal is get the keyframes processed to get on to making the film.


The workflow:

    •    Prompt user to select a range of keyframes. 

    •    Create array of keyframe values from selection. 

    •    Set first keyframe in selection to 0.0. 

    •    Set second keyframe in selection to 100.0.  

    •    Set last keyframe in selection to 0.0. 

    •    In a loop find any elements in array that are > 0.0 and < 100.0 and delete them. 


My problem is that the last actual programming experience I’ve had was 40 years ago in a community college course in c++. I’ve had no experience in Javascript which After Effects uses. 

I’m using a M1 Pro MacBook Pro running Tahoe 26.5.1 with 32 GB memory.

Can anyone off some assistance/advice how to accomplish this? Thanks in advance.

Charles Bandla

Rochester, ny

      2 replies

      davidwarner11t
      davidwarner11t
      Participating Frequently
      August 4, 2026

      This should be straightforward with an After Effects JavaScript ExtendScript. Select the keyframes loop through them from the last to the first, and delete any values between 0 and 100. Then set the first, second, and last keyframes to 0, 100, and 0. Working backward is important so deleting keyframes doesn't mess up the indexes.

      Dan Ebberts
      Community Expert
      Dan EbbertsCommunity Expert
      Community Expert
      August 3, 2026

      This is pretty rough and could use some better error checking, but it should give you the idea:

      function processKeys(){
      	var myProps = app.project.activeItem.selectedProperties;
      	var myProp;
      	var myKeys = [];
      	var keysToRemove = [];
      	app.beginUndoGroup("Prkocess Keyframes");
      	for (var i = 0; i < myProps.length; i++){
      		myProp = myProps[i];
      		if (myProp.isTimeVarying){
      			myKeys = myProp.selectedKeys;
      			if (myKeys.length >= 3){
      				for (var j = 0; j < myKeys.length; j++){
      					if (j == 0){
      						myProp.setValueAtKey(myKeys[0],0.0)
      					}else if (j == 1){
      						myProp.setValueAtKey(myKeys[1],100.0)
      					}else if (j == myKeys.length - 1){
      						myProp.setValueAtKey(myKeys[myKeys.length-1],0.0);
      					}else{
      						if (myProp.valueAtTime(myProp.keyTime(myKeys[j]),false) > 0.0 && myProp.valueAtTime(myProp.keyTime(myKeys[j]),false) < 100.0){
      							keysToRemove.push(myKeys[j]);
      						}
      					}
      				}
      				while (keysToRemove.length > 0){
      					myProp.removeKey(keysToRemove.pop());
      				}
      			}else{
      				alert ("Less than 3 keys selected.");
      				return;
      			}
      		}
      	}
      	app.endUndoGroup();
      }
      processKeys();

       

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