audio latency

hi, I developped a video chat application, but I have a big problem, I can't find the setttings for have a least latency as possible, either the video quality is bad or the latency is up than 5 secondes...What should i do?

Globals.vars.camW=640;

Globals.vars.camH=480;

Globals.vars.camFPS=10;

cam.setMode(Globals.vars.camW, Globals.vars.camH, Globals.vars.camFPS);
cam.setKeyFrameInterval(48);
cam.setQuality(getQuality(),0);

private function getQuality(e:*= null):Number
        {
            var value:Number;
            if (Globals.vars.appel.appelant == Globals.vars.myUser.Id)
            {
                //on regle la qualité sur la band passante obtenue dans les tests à laquelle on retire la bande passante utilisé par l'audio soit 23.8/8=2.975koctet
                value= 0.9*(Globals.vars.appel.appelantBwUp - 2.975) * 1000;
            }
            else if(Globals.vars.appel.appele == Globals.vars.myUser.Id)
            {
                value=0.9*(Globals.vars.appel.appeleBwUp-2.975)*1000;                   
            }
            return value;       
        }