diff --git a/templates/course.html b/templates/course.html
index 587740c622aa05cf358d6e6420511991e1c053fd..d074dce091c081d7eadad0181398963f148d75fc 100644
--- a/templates/course.html
+++ b/templates/course.html
@@ -161,7 +161,7 @@
 							{% endfor %}
 						</select>
 						<img src="{{ url_for('static', filename='smptebars.jpg') }}" style="width: 100%; margin-bottom: 0.5em; margin-top: 0.5em"/>
-						<div class="checkbox"><label><input name="source{{num }}_deinterlace" type="checkbox">Video deinterlacen</label></div>
+						<div class="checkbox"><label><input name="source{{ snum }}_deinterlace" type="checkbox">Video deinterlacen</label></div>
 						<label>Lautstärke</label>
 						<div class="row">
 							<div class="col-xs-6">