CC-3566: Preferences->"Fade In" is not respected when Show starts

- adding some comments

python_apps/pypo/liquidsoap_scripts/ls_script.liq

@@ -29,6 +29,7 @@ s3_namespace = ref ''
 
 queue = on_metadata(notify, queue)
 queue = map_metadata(append_title, queue)
+# the crossfade function controls fade in/out
 queue = crossfade(queue)
 ignore(output.dummy(queue, fallible=true))
 

python_apps/pypo/pypopush.py

@@ -429,6 +429,7 @@ class PypoPush(Thread):
             self.telnet_lock.release()
             
     def create_liquidsoap_annotation(self, media):        
+        # we need lia_start_next value in the annotate. That is the value that controlls overlap duration of crossfade.
         return 'annotate:media_id="%s",liq_start_next="0",liq_fade_in="%s",liq_fade_out="%s",liq_cue_in="%s",liq_cue_out="%s",schedule_table_id="%s":%s' \
             % (media['id'], float(media['fade_in'])/1000, float(media['fade_out'])/1000, float(media['cue_in']), float(media['cue_out']), media['row_id'], media['dst'])