fps not work

[marsiliflavio]

hi,
i have this code
document.addEventListener('deviceready', function () {
var objCanvas = document.getElementById('canvas');
window.plugin.CanvasCamera.initialize(objCanvas);
var cameraOptions = {
width: window.screen.width,
height: window.screen.height,
canvas: {
width: window.screen.width,
height: window.screen.height
},
capture: {
width: window.screen.width,
height: window.screen.height
},
fps: 1,
use: 'data',
flashMode: false,
thumbnailRatio: 1/6,
cameraFacing: 'front',
onBeforeDraw: function(frame){

      },
      onAfterDraw: function(frame){
        //save in list
      }
    };
    window.plugin.CanvasCamera.start($scope.cameraOptions, function(error) {
      
    }, function(data) {
      
    });
}, true);

the camera is ready in canvas, but capture 30 frames/sec. My array contains after 2 seconds about 60 frames. But i have set 1 fps and i suppose max 2 frames after 2 seconds.