fix issue with recording url construction

ruby/lib/jam_ruby/models/music_session_history.rb

@@ -47,12 +47,14 @@ module JamRuby
       tracks = []
       self.music_session_user_histories.each do |msuh|
         user = User.find(msuh.user_id)
-        instruments = msuh.instruments.split(SEPARATOR)
-        instruments.each do |instrument|
-          t = Track.new
-          t.musician = user
-          t.instrument_id = instrument
-          tracks << t
+        unless msuh.instruments.blank?
+          instruments = msuh.instruments.split(SEPARATOR)
+          instruments.each do |instrument|
+            t = Track.new
+            t.musician = user
+            t.instrument_id = instrument
+            tracks << t
+          end
         end
       end
       tracks

web/app/views/recordings/show.html.erb

@@ -62,8 +62,8 @@
       <div class="recording-current">0:00</div>
       <audio controls preload="none" style="display:none;">
         <% if @claimed_recording.has_mix? %>
-          <source src="<%= @claimed_recording.download_url(@claimed_recording.id, 'mp3') %>">
-          <source src="<%= @claimed_recording.download_url(@claimed_recording.id, 'ogg') %>">
+          <source src="<%= claimed_recording_download_url(@claimed_recording.id, 'mp3') %>" type="mp3">
+          <source src="<%= claimed_recording_download_url(@claimed_recording.id, 'ogg') %>" type="ogg">
         <% end %>
       </audio>
       <% if !@claimed_recording.has_mix? %>