function convertSMPTEtoSeconds (SMPTE) {

	if (typeof SMPTE !== 'string') {
		throw new TypeError('Argument must be a string value');
	}

	SMPTE = SMPTE.replace(',', '.');

	const decimalLen = ~SMPTE.indexOf('.') ? SMPTE.split('.')[1].length : 0;

	let
		secs = 0,
		multiplier = 1
	;

	SMPTE = SMPTE.split(':').reverse();

	for (let i = 0, total = SMPTE.length; i < total; i++) {
		multiplier = 1;
		if (i > 0) {
			multiplier = Math.pow(60, i);
		}
		secs += Number(SMPTE[i]) * multiplier;
	}
	return Number(secs.toFixed(decimalLen));
}
Convert Society of Motion Picture and Television Engineers (SMTPE) time code into seconds

@param {String} SMPTE
@return {Number}