diff --git a/libswresample/swresample.c b/libswresample/swresample.c
index c325513efa..fc58d43664 100644
--- a/libswresample/swresample.c
+++ b/libswresample/swresample.c
@@ -668,8 +668,8 @@ int swr_convert(struct SwrContext *s, uint8_t *out_arg[SWR_CH_MAX], int out_coun
             continue;
         }
 
-        if(s->drop_output || !out_arg)
-            return 0;
+        av_assert0(s->drop_output);
+        return 0;
     }
 
     if(!in_arg){