diff --git a/vpx/vp8cx.h b/vpx/vp8cx.h
index f7dde6272cfb2258eff56bdf5e98c68f596deede..0b637d42f936cd0b10ea7f80fc7e304bd690dde2 100644
--- a/vpx/vp8cx.h
+++ b/vpx/vp8cx.h
@@ -195,6 +195,11 @@ enum vp8e_enc_control_id {
 
   VP9E_SET_SVC,
   VP9E_SET_SVC_PARAMETERS,
+  /*!\brief control function to set svc layer for spatial and temporal.
+   * \note Valid ranges: 0..#vpx_codec_enc_cfg::ss_number_layers for spatial
+   *                     layer and 0..#vpx_codec_enc_cfg::ts_number_layers for
+   *                     temporal layer.
+   */
   VP9E_SET_SVC_LAYER_ID
 };