text: BoxParser.prftBox.prototype.parse = function(stream) {
  	this.parseFullHeader(stream);
  	this.ref_track_id = stream.readUint32();
  	this.ntp_timestamp = stream.readUint64();
  	if (this.version === 0) {
  		this.media_time = stream.readUint32();
  	} else {
  		this.media_time = stream.readUint64();
  	}
  }
  
  