no longer showing download/play button if there are no videos

templates/macros.html

@@ -91,7 +91,7 @@
 {% endmacro %}
 
 {% macro video_download_btn(videos) %}
-<button class="btn btn-primary dropdown-toggle" type="button" data-toggle="dropdown">Download <span class="caret"></span></button>
+<button class="btn btn-primary dropdown-toggle {% if videos|length is equalto 0 %}disabled{% endif %}" type="button" data-toggle="dropdown">Download <span class="caret"></span></button>
 <ul class="dropdown-menu">
 	{% for v in videos %}
 	<li><a href="https://video.fsmpi.rwth-aachen.de/{{v.path}}">{{v.format_description}} ({{v.file_size|filesizeformat(true)}})</a></li>
@@ -142,7 +142,7 @@ $('#embedcodebtn').popover(
 					{{ video_download_btn(videos) }}
 				</span>
 				<a href="/play?lectureid={{lecture.id}}">
-					<button class="btn btn-default" type="button">
+					<button class="btn btn-default {% if videos|length is equalto 0 %}disabled{% endif %}" type="button">
 						<span class="glyphicon glyphicon-play"></span>
 						<span>Play</span>
 					</button>