Adobe AfterEffects

countdown_expr.js

/**
 * Expression for displaying up- or countdowns
 * @credits to https://forums.adobe.com/thread/2191716
 */

rate = 1;
direction = 'down';
type = 'full';

clockStart = 0;
 
function padZero(n) {
	return n < 10 ? "0" + n : "" + n;
}
 
clockTime = clockStart + rate * (time - ('down' === direction  ? outPoint : inPoint));

sign = "";
if (clockTime < 0) {
	if ('down' !== direction) {
		sign = "-";
	}
	clockTime = -clockTime;
}
 
t = Math.floor(clockTime);
hr = Math.floor(t/3600);
min = Math.floor((t%3600)/60);
sec = Math.floor(t%60);
ms = clockTime.toFixed(3).substr(-3);

switch (type) {
	case 'full' :
	case 'hh:mm:ss:ms' :
		sign + padZero(hr) + ":" + padZero(min) + ":" + padZero(sec) + ":" + ms;
		break;
	case 'hh:mm:ss' :
		sign + padZero(hr) + ":" + padZero(min) + ":" + padZero(sec);
		break;
	case 'hh' :
		sign + padZero(hr);
		break;
	case 'mm:ss' :
		min = (hr * 60) + min;
		sign + padZero(min) + ":" + padZero(sec);
		break;
	case 'mm' :
		min = (hr * 60) + min;
	case 'xx:mm:xx' :
	case 'mm_digets' :
		sign + padZero(min);
		break;
	case 'ss' :
		sec = (hr * 3600) +  (min * 60) + sec;
	case 'xx:xx:ss' :
	case 'ss_digets' :
		sign + padZero(sec);
		break;
}