Index: main/channel.c
===================================================================
--- main/channel.c	(revision 324908)
+++ main/channel.c	(working copy)
@@ -4878,6 +4878,10 @@
 			apply_plc(chan, fr);
 		}
 
+		if ((!(fr->subclass.codec & chan->nativeformats)) && (chan->writeformat != fr->subclass.codec)) {
+			ast_set_write_format(chan, fr->subclass.codec);
+		}
+
 		/* If the frame is in the raw write format, then it's easy... just use the frame - otherwise we will have to translate */
 		if (fr->subclass.codec == chan->rawwriteformat)
 			f = fr;