diff --git a/apex/mediatranscoding.rc b/apex/mediatranscoding.rc
index ae9f8ba..6e453be 100644
--- a/apex/mediatranscoding.rc
+++ b/apex/mediatranscoding.rc
@@ -1,3 +1,7 @@
+##  for SDK releases 29..31
+##  where writepid has not yet been replaced by task_profiles
+##
+#
 # media.transcoding service is defined on com.android.media apex which goes back
 # to API29, but we only want it started on API31+ devices. So we declare it as
 # "disabled" and start it explicitly on boot.