diff --git a/gst-libs/gst/pbutils/encoding-profile.c b/gst-libs/gst/pbutils/encoding-profile.c
index 616a1e3fb0..5f25aa7c32 100644
--- a/gst-libs/gst/pbutils/encoding-profile.c
+++ b/gst-libs/gst/pbutils/encoding-profile.c
@@ -609,7 +609,7 @@ gst_encoding_profile_get_restriction (GstEncodingProfile * profile)
 /**
  * gst_encoding_profile_set_name:
  * @profile: a #GstEncodingProfile
- * @name: the name to set on the profile
+ * @name: (allow-none): the name to set on the profile
  *
  * Set @name as the given name for the @profile. A copy of @name will be made
  * internally.
@@ -626,7 +626,7 @@ gst_encoding_profile_set_name (GstEncodingProfile * profile, const gchar * name)
 /**
  * gst_encoding_profile_set_description:
  * @profile: a #GstEncodingProfile
- * @description: the description to set on the profile
+ * @description: (allow-none): the description to set on the profile
  *
  * Set @description as the given description for the @profile. A copy of
  * @description will be made internally.
@@ -713,7 +713,7 @@ gst_encoding_profile_set_preset (GstEncodingProfile * profile,
 /**
  * gst_encoding_profile_set_preset_name:
  * @profile: a #GstEncodingProfile
- * @preset_name: The name of the preset to use in this @profile.
+ * @preset_name: (allow-none): The name of the preset to use in this @profile.
  *
  * Sets the name of the #GstPreset's factory to be used in the profile.
  */
@@ -764,7 +764,7 @@ gst_encoding_profile_set_enabled (GstEncodingProfile * profile,
 /**
  * gst_encoding_profile_set_restriction:
  * @profile: a #GstEncodingProfile
- * @restriction: (transfer full): the restriction to apply
+ * @restriction: (allow-none) (transfer full): the restriction to apply
  *
  * Set the restriction #GstCaps to apply before the encoder
  * that will be used in the profile. See gst_encoding_profile_get_restriction()
diff --git a/gst-libs/gst/pbutils/encoding-target.c b/gst-libs/gst/pbutils/encoding-target.c
index 04e3fb8f51..539cfc440a 100644
--- a/gst-libs/gst/pbutils/encoding-target.c
+++ b/gst-libs/gst/pbutils/encoding-target.c
@@ -696,7 +696,7 @@ empty_name:
 
 /**
  * gst_encoding_target_load_from_file:
- * @filepath: The file location to load the #GstEncodingTarget from
+ * @filepath: (type filename): The file location to load the #GstEncodingTarget from
  * @error: If an error occured, this field will be filled in.
  *
  * Opens the provided file and returns the contained #GstEncodingTarget.
@@ -913,7 +913,7 @@ invalid_category:
 /**
  * gst_encoding_target_save_to_file:
  * @target: a #GstEncodingTarget
- * @filepath: the location to store the @target at.
+ * @filepath: (type filename): the location to store the @target at.
  * @error: If an error occured, this field will be filled in.
  *
  * Saves the @target to the provided file location.
diff --git a/gst-libs/gst/pbutils/gstdiscoverer.c b/gst-libs/gst/pbutils/gstdiscoverer.c
index 09936160ca..06e03a2022 100644
--- a/gst-libs/gst/pbutils/gstdiscoverer.c
+++ b/gst-libs/gst/pbutils/gstdiscoverer.c
@@ -256,10 +256,11 @@ gst_discoverer_class_init (GstDiscovererClass * klass)
    * GstDiscoverer::discovered:
    * @discoverer: the #GstDiscoverer
    * @info: the results #GstDiscovererInfo
-   * @error: (type GLib.Error): #GError, which will be non-NULL if an error
-   *                            occurred during discovery. You must not
-   *                            free this #GError, it will be freed by
-   *                            the discoverer.
+   * @error: (allow-none) (type GLib.Error): #GError, which will be non-NULL
+   *                                         if an error occurred during
+   *                                         discovery. You must not free
+   *                                         this #GError, it will be freed by
+   *                                         the discoverer.
    *
    * Will be emitted in async mode when all information on a URI could be
    * discovered, or an error occurred.