This code is meant to answer Paulinatc's question http://www.portugal-a-programar.pt/topic/61213-botoes-de-controle-para-movieclipe-as3/

AnimationPlayback.as

var aRebobinar:Boolean = false;

botaoesquerda.addEventListener(MouseEvent.CLICK, animar);
botaodireita.addEventListener(MouseEvent.CLICK, retroceder);
mcinvi.addEventListener(MouseEvent.ROLL_OVER, parar);
mcinvi.addEventListener(MouseEvent.ROLL_OUT, tocar);

mcinvi.buttonMode = true;

function parar(event:MouseEvent)
{
    mcinvi.removeEventListener(Event.ENTER_FRAME, retrocederQuadroAQuadro);
    mcinvi.stop();
}
	
function tocar(event:MouseEvent)
{
    if (aRebobinar) {
        retroceder(null);
    } else {
        mcinvi.play();
    }
}

function animar(event:MouseEvent):void
{
    mcinvi.removeEventListener(Event.ENTER_FRAME, retrocederQuadroAQuadro);
    mcinvi.play();
    aRebobinar = false;
}

function retroceder(event:MouseEvent):void
{
    if (!mcinvi.hasEventListener(Event.ENTER_FRAME))
    {  
        mcinvi.addEventListener(Event.ENTER_FRAME, retrocederQuadroAQuadro);
        aRebobinar = true;
    }
}

function retrocederQuadroAQuadro(event:Event):void
{
    if (mcinvi.currentFrame == 1)
    {
        mcinvi.gotoAndStop(mcinvi.totalFrames);
    }
    else 
    {
        mcinvi.prevFrame();
    }
}