var step_r_0='images/step_r_0.gif';
var step_r_1='images/step_r_1.gif';
var ffwd_r_0='images/ffwd_r_0.gif';
var ffwd_r_1='images/ffwd_r_1.gif';
var play_r_0='images/play_r_0.gif';
var play_r_1='images/play_r_1.gif';
var pause_0='images/pause_0.gif';
var pause_1='images/pause_1.gif';
var play_f_0='images/play_f_0.gif';
var play_f_1='images/play_f_1.gif';
var ffwd_f_0='images/ffwd_f_0.gif';
var ffwd_f_1='images/ffwd_f_1.gif';
var step_f_0='images/step_f_0.gif';
var step_f_1='images/step_f_1.gif';


// fast forward or rewind speed per second
var iff_vel = 300;
// play or backwards speed per second
var if_vel = 50;

// fast forward or rewind speed per second
var ff_vel = 400;
// play or backwards speed per second
var f_vel = 25;
// pixels to move when step is pressed.
var step = 400;
// number of milliseconds per frame to start off with
var tstep = 56;
// number of steps before check and correct
var difstep = 3;

var timer = false;
var date = -1;
var tdate = 0;
var tint = 1000;
var stepdif = 0;
var hovVel = 0;
var tcount = 0;
var dif = 56;

function setVelocity(v) {
	cvel = v;
	vel = v;
}

function initTransport() {
	forwards();
}

function startTimer() {
	if (!timer) {
		timer = true;
		date = new Date().getTime();
		dif = tstep;
		stepT();
	}
}

function stepT() {
	if (timer) {
		moveMarquee(tstep * cvel);
//		dd = date;
//		date = new Date().getTime();
//		dif = date - dd;
//		if (dif - 30 > 56) {
//			cvel += cvel < 0 ? 1 : -1;
//		} else if (dif < 56) {
//			cvel += cvel < 0 ? (cvel < vel ? 1 : 0) : (cvel < vel ? -1 : 0);
//		}
		setTimeout(function(){stepT()}, tstep);
		tcount++;
	}
}

function stopTimer() {
	if (timer) {
		//clearInterval(timer);
		timer = false;
		date = -1;
	}
}

function stepb() {
	roll('step_back', step_r_1);
	stopTimer();
	moveMarquee(step);
	roll('pause_button', pause_1);
	roll('step_back', step_r_0);
}

function rrwd() {
	clearButtons();
	setVelocity(ff_vel/tint);
	startTimer();
	roll('rewind', ffwd_r_1);
}

function backwards(){
	clearButtons();
	setVelocity(f_vel/tint);
	startTimer();
	roll('play_back', play_r_1);
}

function pause(){
	if (!timer) {
		startTimer();
		roll('pause_button', pause_0);
	} else {
		stopTimer();
		roll('pause_button', pause_1);
	}
}

function forwards() {
	clearButtons();
	setVelocity(-(f_vel/tint));
	startTimer();
	roll('play_button', play_f_1);
}

function ffwd() {
	clearButtons();
	setVelocity(-(ff_vel/tint));
	startTimer();
	roll('fast_forward', ffwd_f_1);
}

function stepf() {
	roll('step_forward', step_f_1);
	stopTimer();
	moveMarquee(-step);
	roll('pause_button', pause_1);
	roll('step_forward', step_f_0);
}

function hoverIn() {
	//hovVel = vel;
	//vel = 0;
}

function hoverOut() {
	//vel = hovVel;
}

function clearButtons() {
	roll('step_back', step_r_0);
	roll('rewind', ffwd_r_0);
	roll('play_back', play_r_0);
	roll('pause_button', pause_0);
	roll('play_button', play_f_0);
	roll('fast_forward', ffwd_f_0);
	roll('step_forward', step_f_0);
}

function roll(id, img_src) {
   //var im_src = id == 'playbutton'
   document.getElementById(id).src = img_src;
}