diff --git a/os/layers/participant/package-lists/participant.list.chroot b/os/layers/participant/package-lists/participant.list.chroot
index cac11fb..a35a1c5 100644
--- a/os/layers/participant/package-lists/participant.list.chroot
+++ b/os/layers/participant/package-lists/participant.list.chroot
@@ -26,6 +26,8 @@ gcc g++ gdb ddd valgrind python3 pypy3
 evince gnome-terminal konsole xterm byobu make cmake
 nautilus-extension-gnome-terminal
 file-roller
+# video codecs for grader gifs
+libavcodec59
 # for drawing on screenshots
 drawing
 # documentation