diff --git a/python_apps/pypo/liquidsoap_scripts/fdkaac.liq b/python_apps/pypo/liquidsoap_scripts/fdkaac.liq
index 491606802..0c6945221 100644
--- a/python_apps/pypo/liquidsoap_scripts/fdkaac.liq
+++ b/python_apps/pypo/liquidsoap_scripts/fdkaac.liq
@@ -1,24 +1,24 @@
             if bitrate == 24 then 
-                ignore(output_stereo(%fdkaac(bitrate = 24), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 24, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 32 then
-                ignore(output_stereo(%fdkaac(bitrate = 32), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 32, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 48 then
-                ignore(output_stereo(%fdkaac(bitrate = 48), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 48, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 64 then
-                ignore(output_stereo(%fdkaac(bitrate = 64), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 64, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 96 then
-                ignore(output_stereo(%fdkaac(bitrate = 96), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 96, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 128 then
-                ignore(output_stereo(%fdkaac(bitrate = 128), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 128, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 160 then
-                ignore(output_stereo(%fdkaac(bitrate = 160), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 160, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 192 then
-                ignore(output_stereo(%fdkaac(bitrate = 192), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 192, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 224 then
-                ignore(output_stereo(%fdkaac(bitrate = 224), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 224, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 256 then
-                ignore(output_stereo(%fdkaac(bitrate = 256), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 256, aot="mpeg4_he_aac_v2"), !source))
             elsif bitrate == 320 then
-                ignore(output_stereo(%fdkaac(bitrate = 320), !source))
+                ignore(output_stereo(%fdkaac(bitrate = 320, aot="mpeg4_he_aac_v2"), !source))
             end
 
diff --git a/python_apps/pypo/liquidsoap_scripts/ls_lib.liq b/python_apps/pypo/liquidsoap_scripts/ls_lib.liq
index 54530a755..e2123e26d 100644
--- a/python_apps/pypo/liquidsoap_scripts/ls_lib.liq
+++ b/python_apps/pypo/liquidsoap_scripts/ls_lib.liq
@@ -5,7 +5,8 @@ def notify(m)
 end
 
 def notify_queue(m)
-  queue_metadata := m
+  f = !dynamic_metadata_callback
+  ignore(f(m))
   notify(m)
 end
 
@@ -22,17 +23,20 @@ end
 # A function applied to each metadata chunk
 def append_title(m) =  
   log("Using stream_format #{!stream_metadata_type}")
-  if !stream_metadata_type == 1 then
-    [("title", "#{!show_name} - #{m['artist']} - #{m['title']}")]
-  elsif !stream_metadata_type == 2 then
-    [("title", "#{!station_name} - #{!show_name}")]
-  else
-    [("title", "#{m['artist']} - #{m['title']}")]
-  end
-end
 
-def queue_metadata_callback(m) =
-    !queue_metadata
+  if list.mem_assoc("mapped", m) then
+    #protection against applying this function twice. It shouldn't be happening
+    #and bug file with Liquidsoap.
+    m
+  else
+      if !stream_metadata_type == 1 then
+        [("title", "#{!show_name} - #{m['artist']} - #{m['title']}"), ("mapped", "true")]
+      elsif !stream_metadata_type == 2 then
+        [("title", "#{!station_name} - #{!show_name}"), ("mapped", "true")]
+      else
+        [("title", "#{m['artist']} - #{m['title']}"), ("mapped", "true")]
+      end
+  end
 end
 
 def crossfade_airtime(s)
diff --git a/python_apps/pypo/liquidsoap_scripts/ls_script.liq b/python_apps/pypo/liquidsoap_scripts/ls_script.liq
index 15ffeffa1..36d85a372 100644
--- a/python_apps/pypo/liquidsoap_scripts/ls_script.liq
+++ b/python_apps/pypo/liquidsoap_scripts/ls_script.liq
@@ -24,7 +24,7 @@ default_dj_fade = ref 0.
 station_name = ref ''
 show_name = ref ''
 
-queue_metadata = ref []
+dynamic_metadata_callback = ref fun (s) -> begin () end
 
 s1_connected = ref ''
 s2_connected = ref ''
@@ -72,7 +72,9 @@ create_source()
 
 queue = add(!sources, normalize=false)
 
-queue = map_metadata(update=false, queue_metadata_callback, queue)
+pair = insert_metadata(queue)
+dynamic_metadata_callback := fst(pair)
+queue = snd(pair)
 
 output.dummy(fallible=true, queue)