diff --git a/src/html5-qrcode.js b/src/html5-qrcode.js
index 3650eff..9a109d3 100644
--- a/src/html5-qrcode.js
+++ b/src/html5-qrcode.js
@@ -25,7 +25,7 @@
 
                 var scan = function() {
                     if (localMediaStream) {
-                        context.drawImage(video, 0, 0, 307, 250);
+                        context.drawImage(video, 0, 0, width, height);
 
                         try {
                             qrcode.decode();