diff --git a/app/services/rasterizer.rb b/app/services/rasterizer.rb
index 06c45ef..7cfca71 100644
--- a/app/services/rasterizer.rb
+++ b/app/services/rasterizer.rb
@@ -5,7 +5,7 @@ class Rasterizer
   BINARY_PATH = (Rails.root + "a2png" + "a2png.sh").to_s
 
   def generate_image(asciicast_url, out_path, time)
-    o, e, t = Open3.capture3("#{BINARY_PATH} #{asciicast_url} #{out_path} #{time}")
+    o, e, t = Open3.capture3("#{BINARY_PATH} '#{asciicast_url}' #{out_path} #{time}")
 
     if t.exitstatus != 0
       raise RuntimeError, "Couldn't generate image from #{asciicast_url}:\n#{o}\n#{e}"