video - html5 camera is blurry - getuserMedia autofocus not working -

did try html5 video capturing image camera on mobile , have problem blurry image? try on samsung phone image sharp, , on lg g4 image blurry (android browser , chrome on both mobile phones). has experience or can explain solution? can phones has these problems?

there snippet of code use:

function startcamera(newsource) {         if (newsource) {             var constraints = {                 audio: false,                 video: {                     optional: [                         { sourceid: newsource },                     ]                 }             };              addvideoandcanvas();              navigator.getusermedia(constraints, onmediasuccess, onmediaerror);          }     }      function addvideoandcanvas() {         self.video = $('<video muted autoplay>');         self.canvas = $('<canvas id="qr-canvas" class="hide">');         $('.modal-body .video-container', self.root).append(self.video).append(self.canvas);     }      function onmediasuccess(stream) {         self.stream = stream;         self.video[0].src = (window.url && window.url.createobjecturl(stream)) || stream;          self.video[0].onloadeddata = function () {                             self.canvas[0].height = self.video[0].videoheight;             self.canvas[0].width = self.video[0].videowidth;             scan();         }                        }      function onmediaerror(error) {                 }      function scan() {         if (self.stream) {                             try {                 var ctx = self.canvas[0].getcontext('2d');                 ctx.drawimage(self.video[0], 0, 0);              } catch (e) {                 settimeout(scan, 20);             }         } else {             settimeout(scan, 20);         }     } 

probably waiting on folowing spec: https://w3c.github.io/mediacapture-image/index.html#focusmode