diff --git a/aom/aomcx.h b/aom/aomcx.h
index 6937a67..c0b0090 100644
--- a/aom/aomcx.h
+++ b/aom/aomcx.h
@@ -222,10 +222,14 @@
 
   /* NOTE: enum 15 unused */
 
-  /*!\brief Codec control function to set loop filter sharpness,
+  /*!\brief Codec control function to set the sharpness parameter,
    * unsigned int parameter.
    *
-   * Valid range: 0..7. The default is 0.
+   * This parameter controls the level at which transform coeff RD favours
+   * sharpness in the block.
+   *
+   * Valid range: 0..7. The default is 0. Values 1-7 will avoid eob and skip
+   * block optimization and will change rdmult in favour of block sharpness.
    */
   AOME_SET_SHARPNESS = AOME_SET_ENABLEAUTOALTREF + 2,  // 16
 
diff --git a/av1/arg_defs.c b/av1/arg_defs.c
index 48d8314..7e34ddf 100644
--- a/av1/arg_defs.c
+++ b/av1/arg_defs.c
@@ -271,7 +271,8 @@
   .noise_sens = ARG_DEF(NULL, "noise-sensitivity", 1,
                         "Noise sensitivity (frames to blur)"),
   .sharpness = ARG_DEF(NULL, "sharpness", 1,
-                       "Loop filter sharpness (0..7), default is 0"),
+                       "Bias towards block sharpness in transform coeff RD "
+                       "(0..7), default is 0"),
   .static_thresh =
       ARG_DEF(NULL, "static-thresh", 1, "Motion detection threshold"),
   .auto_altref =
diff --git a/av1/encoder/encoder.h b/av1/encoder/encoder.h
index b2816f5..c22e2ee 100644
--- a/av1/encoder/encoder.h
+++ b/av1/encoder/encoder.h
@@ -717,7 +717,10 @@
  */
 typedef struct {
   /*!
-   * Indicates the loop filter sharpness.
+   * Controls the level at which transform coeff RD favours sharpness in the
+   * block. Has no impact on RD when set to zero (default). For values 1-7, eob
+   * and skip block optimization are avoided and rdmult is adjusted in favour of
+   * block sharpness.
    */
   int sharpness;
 
diff --git a/av1/encoder/txb_rdopt.h b/av1/encoder/txb_rdopt.h
index e86caaa..12168c1 100644
--- a/av1/encoder/txb_rdopt.h
+++ b/av1/encoder/txb_rdopt.h
@@ -44,11 +44,11 @@
  * skip flag (tx_skip) and the sign of DC coefficient (dc_sign).
  * \param[out]   rate_cost      The entropy cost of coding the transform block
  * after adjustment of coefficients.
- * \param[in]    sharpness      When sharpness == 1, the function will be less
- * aggressive toward lowering the magnitude of coefficients.
+ * \param[in]    sharpness      When sharpness > 0, the function will be less
+ * aggressive towards lowering the magnitude of coefficients.
  * In this way, the transform block will contain more high-frequency
- coefficients
- * and therefore preserve the sharpness of the reconstructed block.
+ * coefficients and therefore, will preserve the sharpness of the reconstructed
+ * block.
  */
 int av1_optimize_txb(const struct AV1_COMP *cpi, MACROBLOCK *x, int plane,
                      int block, TX_SIZE tx_size, TX_TYPE tx_type,