After Effects cubic-bezier exporter

AE CubicBezier.jsx

// Source: https://community.adobe.com/t5/after-effects-discussions/convert-ae-keyframes-info-to-cubicbezier-points/m-p/6139286#M135604

// Usage: select a layer, then File -> Scripts -> Run Script File... -> select this script

var curItem = app.project.activeItem;
var selectedLayers = curItem.selectedLayers;
var selectedProperties = curItem.selectedProperties;
var output="";
if (selectedLayers == 0) {
   output="Please Select at least one Layer";
}
else if (selectedLayers != 0) {
   for (var i = 0; i < selectedLayers.length; i++) {
   for (var f in selectedProperties) {
   var currentProperty = selectedProperties[f];
   if (currentProperty.numKeys > 1) {
   for (var i = 1; i < currentProperty.numKeys; i++) {
   var t1 = currentProperty.keyTime(i);
   var t2 = currentProperty.keyTime(i + 1);
   var val1 = currentProperty.keyValue(i);
   var val2 = currentProperty.keyValue(i + 1);
   //converting float to array
   if (val1.constructor !== Array) {
   var temp = new Array();
   temp[0] = val1;
   val1 = temp;
  }
   if (val2.constructor !== Array) {
   var temp = new Array();
   temp[0] = val2;
   val2 = temp;
  }
   //multi dimension values
   for (var y = 0; y < val1.length; y++) {
   var delta_t = t2 - t1;
   var c_val1 = parseFloat(val1[y]);
   var c_val2 = parseFloat(val2[y]);
   var delta = c_val2 - c_val1;
   avSpeed = Math.abs(delta) / (delta_t);
   /* $.write("val1 " + c_val1 + "--");
  $.write("val2 " + c_val2 + "\n");
  $.write("avSpeed " + avSpeed + "\n");*/
   output+=('dimension ' + y + ':\n');
   //values dispatch
   if (c_val1 != c_val2) {
   getBezier(currentProperty, i, c_val1, c_val2, avSpeed);
  }
   else { //if (c_val1 == c_val2)
   var minmax = getMinMaxPoints(t1, t2, currentProperty, curItem);
   var maxp_val = minmax.maxPoint.value;
  
   var hasmax = true;
   var hasmin = true;
   var minp_val = minmax.minPoint.value;
   if (!(c_val1 < maxp_val) || !(c_val1 > minp_val)) {
   if (c_val1 < maxp_val) {
   //create temp keyframe to "cut" the curve
   var tempkey_i = currentProperty.addKey(minmax.maxPoint.time);
   var tempavSpeed = Math.abs(maxp_val - c_val1) / (minmax.maxPoint.time - t1);
   //get the 2 bezier-curves
   getBezier(currentProperty, i, c_val1, maxp_val, tempavSpeed);//part going up
   getBezier(currentProperty, tempkey_i, maxp_val, c_val1, tempavSpeed);//part going down
   currentProperty.removeKey(tempkey_i);//remove temp key
  }else {
   hasmax = false;
  }
   if (c_val1 > minp_val) {
   var tempkey_i = currentProperty.addKey(minmax.minPoint.time);
   var tempavSpeed = Math.abs(maxp_val - c_val1) / (minmax.minPoint.time - t1);
   getBezier(currentProperty, i, c_val1, minp_val, tempavSpeed);//part going down
   getBezier(currentProperty, tempkey_i, minp_val, c_val1, tempavSpeed);//part going up
   currentProperty.removeKey(tempkey_i);//remove temp key
  }else{
   hasmin = false;
  }
   if(!hasmax || !hasmin)//if flat curve
   output+=("keyframe " + i + " has no animation\n\n");
  } else { //if (c_val1 < maxp_val && c_val1 > minp_val)
   //sort values
   output+=('equal minmax ');
   var first_time, sec_time, first_val, sec_val;
   if (minmax.maxPoint.time < minmax.minPoint.time) {
   //max value if first:
   first_time = minmax.maxPoint.time;
   first_val = maxp_val;
   sec_time = minmax.minPoint.time;
   sec_val = minp_val;
  } else {
   //min value if first:
   first_time = minmax.minPoint.time;
   first_val = minp_val;
   sec_time = minmax.maxPoint.time;
   sec_val = maxp_val;
  }
   // we have 2 extreme points, we need to "cut" twince (it gives 3 curves)
   var tempkey_i = currentProperty.addKey(first_time);
   var tempkey2_i = currentProperty.addKey(sec_time);
   var tempavSpeed_1 = Math.abs(first_val - c_val1) / (first_time - t1);//avspeed 1rst curve
   var tempavSpeed_2 = Math.abs(sec_val - first_val) / (sec_time - first_time);//avspeed 1nd curve
   var tempavSpeed_3 = Math.abs(c_val2 - sec_val) / (t2 - sec_time);//avspeed 3rd curve
   //get the 3 bezier-curves
   getBezier(currentProperty, i, c_val1, first_val, tempavSpeed_1);
   getBezier(currentProperty, tempkey_i, first_val, sec_val, tempavSpeed_2);
   getBezier(currentProperty, tempkey2_i, sec_val, c_val2, tempavSpeed_3);
   currentProperty.removeKey(tempkey_i);//remove temp key
   currentProperty.removeKey(tempkey2_i);//remove temp key
  }
  }//end value dispatch
  }
  }
  }
  }
  }
}

alert(output);

function getMinMaxPoints(t1, t2, currentProperty, curItem) {
   var P = currentProperty;
   var t = t1;
   var min = 999999;
   var max = -999999;
   var tmin = 0;
   var tmax = 0;
   while (t <= t2) {
   var val = P.valueAtTime(t, true);
   if (val > max) {
   max = val;
   tmax = t;
  }
   if (val < min) {
   min = val;
   tmin = t;
  }
   t += curItem.frameDuration;
  }
   if (max == -999999)
   max = P.valueAtTime(t1, true);
   if (min == 999999)
   min = P.valueAtTime(t1, true);
   var maxPoint = {
   value: max,
   time: tmax
  }
   var minPoint = {
   value: min,
   time: tmin
  }
   return { minPoint: minPoint, maxPoint: maxPoint }
}
function getBezier(currentProperty, i, c_val1, c_val2, avSpeed) {
   if (c_val1 < c_val2) {
   x1 = currentProperty.keyOutTemporalEase(i)[0].influence / 100;
   y1 = x1 * currentProperty.keyOutTemporalEase(i)[0].speed / avSpeed;
   x2 = 1 - currentProperty.keyInTemporalEase(i + 1)[0].influence / 100;
   y2 = 1 - (1 - x2) * (currentProperty.keyInTemporalEase(i + 1)[0].speed / avSpeed);
  }
   if (c_val2 < c_val1) {
   x1 = currentProperty.keyOutTemporalEase(i)[0].influence / 100;
   y1 = (-x1) * currentProperty.keyOutTemporalEase(i)[0].speed / avSpeed;
   x2 = currentProperty.keyInTemporalEase(i + 1)[0].influence / 100;
   y2 = 1 + x2 * (currentProperty.keyInTemporalEase(i + 1)[0].speed / avSpeed);
   x2 = 1 - x2;
  }
   output+=("keyframe: " + i + " Cubic-bezier[" + x1.toFixed(2) + ", " + y1.toFixed(2) + ", " + x2.toFixed(2) + ", " + y2.toFixed(2) + "]\n\n");
}