diff --git a/aom/aomcx.h b/aom/aomcx.h
index 0f7a5b9..9771702 100644
--- a/aom/aomcx.h
+++ b/aom/aomcx.h
@@ -209,7 +209,10 @@
 
   /* NOTE: enum 15 unused */
 
-  /*!\brief Codec control function to set sharpness, unsigned int parameter.
+  /*!\brief Codec control function to set loop filter sharpness,
+   * unsigned int parameter.
+   *
+   * Valid range: 0..7. The default is 0.
    */
   AOME_SET_SHARPNESS = AOME_SET_ENABLEAUTOALTREF + 2,  // 16
 
diff --git a/apps/aomenc.c b/apps/aomenc.c
index 1b96ac2..425f043 100644
--- a/apps/aomenc.c
+++ b/apps/aomenc.c
@@ -386,7 +386,7 @@
 static const arg_def_t noise_sens =
     ARG_DEF(NULL, "noise-sensitivity", 1, "Noise sensitivity (frames to blur)");
 static const arg_def_t sharpness =
-    ARG_DEF(NULL, "sharpness", 1, "Loop filter sharpness (0..7)");
+    ARG_DEF(NULL, "sharpness", 1, "Loop filter sharpness (0..7), default is 0");
 static const arg_def_t static_thresh =
     ARG_DEF(NULL, "static-thresh", 1, "Motion detection threshold");
 static const arg_def_t auto_altref =