CC-3641: Stream Transition: When a song is added to the for the first time

, the transition fade effects fade in

- fixed

python_apps/pypo/liquidsoap_scripts/ls_lib.liq

@@ -32,6 +32,24 @@ def transition(a,b) =
         fade.final(duration=!default_dj_fade, a) ])
 end
 
+# we need this function for special transition case(from default to queue)
+# we don't want the trasition fade to have effect on the first song that would
+# be played siwtching out of the default(silent) source
+def transition_default(a,b) =
+  log("transition called...")
+  if !just_switched then
+      just_switched := false
+      add(normalize=false,
+         [ sequence([ blank(duration=0.01),
+                       fade.initial(duration=!default_dj_fade, b) ]),
+            fade.final(duration=!default_dj_fade, a) ])
+  else
+    just_switched := false
+    b
+  end
+end
+
+
 # Define a transition that fades out the
 # old source, adds a single, and then 
 # plays the new source

python_apps/pypo/liquidsoap_scripts/ls_script.liq

@@ -24,6 +24,7 @@ s3_connected = ref ''
 s1_namespace = ref ''
 s2_namespace = ref ''
 s3_namespace = ref ''
+just_switched = ref false
 
 %include "ls_lib.liq"
 
@@ -47,9 +48,9 @@ default = amplify(id="silence_src", 0.00001, noise())
 default = rewrite_metadata([("artist","Airtime"), ("title", "offline")],default)
 ignore(output.dummy(default, fallible=true))
 
-master_dj_enabled = ref false;
+master_dj_enabled = ref false
-live_dj_enabled = ref false;
+live_dj_enabled = ref false
-scheduled_play_enabled = ref false;
+scheduled_play_enabled = ref false
 
 def make_master_dj_available()
         master_dj_enabled := true
@@ -69,6 +70,7 @@ end
 
 def make_scheduled_play_available()
         scheduled_play_enabled := true
+        just_switched := true
 end
 
 def make_scheduled_play_unavailable()
@@ -150,7 +152,7 @@ def append_dj_inputs(master_harbor_input_port, master_harbor_input_mount_point,
     end
 end
 
-s = switch(id="default_switch", track_sensitive=false, transitions=[transition, transition], [({!scheduled_play_enabled},queue),({true},default)])
+s = switch(id="default_switch", track_sensitive=false, transitions=[transition_default, transition], [({!scheduled_play_enabled},queue),({true},default)])
 s = append_dj_inputs(master_live_stream_port, master_live_stream_mp, dj_live_stream_port, dj_live_stream_mp, s)
 
 # Attach a skip command to the source s: