diff --git a/ges/ges-asset.c b/ges/ges-asset.c
index 35ff2210ce..ab6499eb5b 100644
--- a/ges/ges-asset.c
+++ b/ges/ges-asset.c
@@ -477,7 +477,7 @@ _gtask_return_true (GTask * task, gpointer udata)
  *
  * Looks for asset with specified id in cache and it's completely loaded.
  *
- * Returns: (transfer none): The #GESAsset found or %NULL
+ * Returns: (transfer none) (nullable): The #GESAsset found or %NULL
  */
 GESAsset *
 ges_asset_cache_lookup (GType extractable_type, const gchar * id)
@@ -770,7 +770,7 @@ ges_asset_list_proxies (GESAsset * asset)
  * ges_asset_get_proxy:
  * @asset: The #GESAsset to get currenlty used proxy
  *
- * Returns: (transfer none): The proxy in use for @asset
+ * Returns: (transfer none) (nullable): The proxy in use for @asset
  */
 GESAsset *
 ges_asset_get_proxy (GESAsset * asset)
@@ -788,7 +788,7 @@ ges_asset_get_proxy (GESAsset * asset)
  * ges_asset_get_proxy_target:
  * @proxy: The #GESAsset from which to get the the asset it proxies.
  *
- * Returns: (transfer none): The #GESAsset that is proxied by @proxy
+ * Returns: (transfer none) (nullable): The #GESAsset that is proxied by @proxy
  */
 GESAsset *
 ges_asset_get_proxy_target (GESAsset * proxy)
@@ -1283,8 +1283,8 @@ ges_list_assets (GType filter)
  * ges_asset_get_error:
  * @self: The asset to retrieve the error from
  *
- * Returns: (transfer none): The #GError of the asset or %NULL if the asset was
- * loaded without issue
+ * Returns: (transfer none) (nullable): The #GError of the asset or %NULL if
+ * the asset was loaded without issue
  *
  * Since: 1.8
  */
diff --git a/ges/ges-audio-test-source.c b/ges/ges-audio-test-source.c
index a49e632dc1..5802bacfb6 100644
--- a/ges/ges-audio-test-source.c
+++ b/ges/ges-audio-test-source.c
@@ -183,7 +183,7 @@ ges_audio_test_source_get_freq (GESAudioTestSource * self)
 /**
  * ges_audio_test_source_get_volume:
  * @self: a #GESAudioTestSource
- * 
+ *
  * Get the current volume of @self.
  *
  * Returns: The current volume of @self
@@ -203,7 +203,7 @@ ges_audio_test_source_get_volume (GESAudioTestSource * self)
  *
  * Creates a new #GESAudioTestSource.
  *
- * Returns: The newly created #GESAudioTestSource.
+ * Returns: (transfer floating) (nullable): The newly created #GESAudioTestSource.
  */
 GESAudioTestSource *
 ges_audio_test_source_new (void)
diff --git a/ges/ges-audio-track.c b/ges/ges-audio-track.c
index 57e7e3a302..5486e69f7e 100644
--- a/ges/ges-audio-track.c
+++ b/ges/ges-audio-track.c
@@ -114,7 +114,7 @@ ges_audio_track_class_init (GESAudioTrackClass * klass)
  * Creates a new #GESAudioTrack of type #GES_TRACK_TYPE_AUDIO and with generic
  * raw audio caps ("audio/x-raw");
  *
- * Returns: A new #GESTrack
+ * Returns: (transfer floating): A new #GESTrack
  */
 GESAudioTrack *
 ges_audio_track_new (void)
diff --git a/ges/ges-audio-transition.c b/ges/ges-audio-transition.c
index 8d5c297ecf..5d26f2eb9a 100644
--- a/ges/ges-audio-transition.c
+++ b/ges/ges-audio-transition.c
@@ -287,7 +287,7 @@ ges_audio_transition_duration_changed (GESTrackElement * track_element,
  *
  * Creates a new #GESAudioTransition.
  *
- * Returns: The newly created #GESAudioTransition.
+ * Returns: (transfer floating): The newly created #GESAudioTransition.
  */
 GESAudioTransition *
 ges_audio_transition_new (void)
diff --git a/ges/ges-audio-uri-source.c b/ges/ges-audio-uri-source.c
index 7e824b0d39..e75ee2d70b 100644
--- a/ges/ges-audio-uri-source.c
+++ b/ges/ges-audio-uri-source.c
@@ -185,8 +185,8 @@ ges_audio_uri_source_init (GESAudioUriSource * self)
  *
  * Creates a new #GESAudioUriSource for the provided @uri.
  *
- * Returns: The newly created #GESAudioUriSource, or %NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created
+ * #GESAudioUriSource, or %NULL if there was an error.
  */
 GESAudioUriSource *
 ges_audio_uri_source_new (gchar * uri)
diff --git a/ges/ges-clip.c b/ges/ges-clip.c
index 12df14d5f5..a7bcc5d2ed 100644
--- a/ges/ges-clip.c
+++ b/ges/ges-clip.c
@@ -824,8 +824,8 @@ ges_clip_init (GESClip * self)
  * keep a reference to the newly created trackelement, you therefore need to
  * call @ges_container_remove when you are done with it.
  *
- * Returns: (transfer none): A #GESTrackElement. Returns NULL if the #GESTrackElement could not
- * be created.
+ * Returns: (transfer none) (nullable): A #GESTrackElement. Returns NULL if
+ * the #GESTrackElement could not be created.
  */
 GESTrackElement *
 ges_clip_create_track_element (GESClip * clip, GESTrackType type)
@@ -1053,8 +1053,8 @@ ges_clip_move_to_layer (GESClip * clip, GESLayer * layer)
  * Note: If many objects match, then the one with the highest priority will be
  * returned.
  *
- * Returns: (transfer full): The #GESTrackElement used by @track, else %NULL,
- * Unref after usage
+ * Returns: (transfer full) (nullable): The #GESTrackElement used by @track,
+ * else %NULL. Unref after usage
  */
 
 GESTrackElement *
@@ -1090,7 +1090,7 @@ ges_clip_find_track_element (GESClip * clip, GESTrack * track, GType type)
  *
  * Get the #GESLayer to which this clip belongs.
  *
- * Returns: (transfer full): The #GESLayer where this @clip is being
+ * Returns: (transfer full) (nullable): The #GESLayer where this @clip is being
  * used, or %NULL if it is not used on any layer. The caller should unref it
  * usage.
  */
@@ -1265,8 +1265,8 @@ ges_clip_set_top_effect_index (GESClip * clip, GESBaseEffect * effect,
  * property must be registered using @ges_effect_class_register_rate_property;
  * for the 'pitch' plugin, this is already done.
  *
- * Returns: (transfer none): The newly created #GESClip resulting from the
- * splitting
+ * Returns: (transfer none) (nullable): The newly created #GESClip resulting
+ * from the splitting or %NULL if the clip can't be split.
  */
 GESClip *
 ges_clip_split (GESClip * clip, guint64 position)
diff --git a/ges/ges-effect-clip.c b/ges/ges-effect-clip.c
index 00734a108f..055504d34a 100644
--- a/ges/ges-effect-clip.c
+++ b/ges/ges-effect-clip.c
@@ -176,7 +176,7 @@ _create_track_element (GESClip * self, GESTrackType type)
  *
  * Creates a new #GESEffectClip from the description of the bin.
  *
- * Returns: a newly created #GESEffectClip, or
+ * Returns: (transfer floating) (nullable): a newly created #GESEffectClip, or
  * %NULL if something went wrong.
  */
 GESEffectClip *
diff --git a/ges/ges-effect.c b/ges/ges-effect.c
index 652c1c9564..e4fc99372d 100644
--- a/ges/ges-effect.c
+++ b/ges/ges-effect.c
@@ -257,7 +257,7 @@ ges_effect_create_element (GESTrackElement * object)
  * #ges_asset_request (GES_TYPE_EFFECT, "audio your ! bin ! description", NULL);
  * and extract that asset to be in full control.
  *
- * Returns: a newly created #GESEffect, or %NULL if something went
+ * Returns: (nullable): a newly created #GESEffect, or %NULL if something went
  * wrong.
  */
 GESEffect *
diff --git a/ges/ges-extractable.c b/ges/ges-extractable.c
index dad10a0931..0d6af61531 100644
--- a/ges/ges-extractable.c
+++ b/ges/ges-extractable.c
@@ -83,7 +83,8 @@ ges_extractable_default_init (GESExtractableInterface * iface)
  *
  * Method for getting an asset from a #GESExtractable
  *
- * Returns: (transfer none): The #GESAsset or %NULL if none has been set
+ * Returns: (transfer none) (nullable): The #GESAsset or %NULL if none has
+ * been set
  */
 GESAsset *
 ges_extractable_get_asset (GESExtractable * self)
@@ -212,8 +213,8 @@ ges_extractable_type_get_asset_type (GType type)
  *
  * Check if @id is valid for @type
  *
- * Returns: (transfer full): A newly allocated string containing the actuall
- * ID (after some processing) or %NULL if the ID is wrong.
+ * Returns: (transfer full) (nullable): A newly allocated string containing
+ * the actual ID (after some processing) or %NULL if the ID is wrong.
  */
 gchar *
 ges_extractable_type_check_id (GType type, const gchar * id, GError ** error)
diff --git a/ges/ges-group.c b/ges/ges-group.c
index 61bbc49512..b707eb06c0 100644
--- a/ges/ges-group.c
+++ b/ges/ges-group.c
@@ -791,7 +791,7 @@ ges_group_init (GESGroup * self)
  * together, it is recommanded to use the #ges_container_group method so the
  * proper subclass is selected.
  *
- * Returns: The new empty group.
+ * Returns: (transfer floating): The new empty group.
  */
 GESGroup *
 ges_group_new (void)
diff --git a/ges/ges-image-source.c b/ges/ges-image-source.c
index d83e8e29f2..66f3ef3f1d 100644
--- a/ges/ges-image-source.c
+++ b/ges/ges-image-source.c
@@ -181,7 +181,7 @@ ges_image_source_init (GESImageSource * self)
  *
  * Creates a new #GESImageSource for the provided @uri.
  *
- * Returns: A new #GESImageSource.
+ * Returns: (transfer floating): A new #GESImageSource.
  */
 GESImageSource *
 ges_image_source_new (gchar * uri)
diff --git a/ges/ges-layer.c b/ges/ges-layer.c
index 10ed92bc46..ebc69a644d 100644
--- a/ges/ges-layer.c
+++ b/ges/ges-layer.c
@@ -502,7 +502,7 @@ ges_layer_is_empty (GESLayer * layer)
  * are constructed, you should connect to the container::child-added signal which
  * is emited right after those elements are ready to be used.
  *
- * Returns: TRUE if the clip was properly added to the layer, or FALSE
+ * Returns: %TRUE if the clip was properly added to the layer, or %FALSE
  * if the @layer refuses to add the clip.
  */
 gboolean
@@ -662,7 +662,7 @@ ges_layer_add_asset (GESLayer * layer,
  *
  * Creates a new #GESLayer.
  *
- * Returns: A new #GESLayer
+ * Returns: (transfer floating): A new #GESLayer
  */
 GESLayer *
 ges_layer_new (void)
@@ -676,7 +676,7 @@ ges_layer_new (void)
  *
  * Get the #GESTimeline in which #GESLayer currently is.
  *
- * Returns: (transfer none):  the #GESTimeline in which #GESLayer
+ * Returns: (transfer none) (nullable): the #GESTimeline in which #GESLayer
  * currently is or %NULL if not in any timeline yet.
  */
 GESTimeline *
diff --git a/ges/ges-meta-container.c b/ges/ges-meta-container.c
index 1c6da965b2..c9ae58bf2c 100644
--- a/ges/ges-meta-container.c
+++ b/ges/ges-meta-container.c
@@ -426,8 +426,8 @@ ges_meta_container_set_meta (GESMetaContainer * container,
  *
  * Serializes a meta container to a string.
  *
- * Returns: a newly-allocated string, or NULL in case of an error. The
- *    string must be freed with g_free() when no longer needed.
+ * Returns: (nullable): a newly-allocated string, or NULL in case of an error.
+ * The string must be freed with g_free() when no longer needed.
  */
 gchar *
 ges_meta_container_metas_to_string (GESMetaContainer * container)
diff --git a/ges/ges-multi-file-source.c b/ges/ges-multi-file-source.c
index 18b3c1c643..6ac35b0adb 100644
--- a/ges/ges-multi-file-source.c
+++ b/ges/ges-multi-file-source.c
@@ -261,7 +261,7 @@ ges_multi_file_source_init (GESMultiFileSource * self)
  *
  * Creates a new #GESMultiFileSource for the provided @uri.
  *
- * Returns: A new #GESMultiFileSource.
+ * Returns: (transfer floating): A new #GESMultiFileSource.
  */
 GESMultiFileSource *
 ges_multi_file_source_new (gchar * uri)
diff --git a/ges/ges-pipeline.c b/ges/ges-pipeline.c
index b2e9a98dec..7590f07e9f 100644
--- a/ges/ges-pipeline.c
+++ b/ges/ges-pipeline.c
@@ -401,7 +401,7 @@ no_encodebin:
  *
  * Creates a new conveninence #GESPipeline.
  *
- * Returns: the new #GESPipeline.
+ * Returns: (transfer floating): the new #GESPipeline.
  */
 GESPipeline *
 ges_pipeline_new (void)
@@ -921,7 +921,7 @@ _unlink_track (GESPipeline * self, GESTrack * track)
 /**
  * ges_pipeline_set_timeline:
  * @pipeline: a #GESPipeline
- * @timeline: the #GESTimeline to set on the @pipeline.
+ * @timeline: (transfer full): the #GESTimeline to set on the @pipeline.
  *
  * Sets the timeline to use in this pipeline.
  *
@@ -1196,7 +1196,7 @@ ges_pipeline_set_mode (GESPipeline * pipeline, GESPipelineFlags mode)
  * is currently used by the sink. This information can be retrieve from caps
  * associated with the buffer.
  *
- * Returns: (transfer full): a #GstSample or %NULL
+ * Returns: (transfer full) (nullable): a #GstSample or %NULL
  */
 
 GstSample *
@@ -1284,11 +1284,11 @@ ges_pipeline_save_thumbnail (GESPipeline * self, int width, int
  * and height. If -1 is specified for either dimension, it will be left at
  * native size. You can retreive this information from the caps associated
  * with the buffer.
- * 
+ *
  * The caller is responsible for unreffing the returned sample with
  * #gst_sample_unref.
  *
- * Returns: (transfer full): a #GstSample or %NULL
+ * Returns: (transfer full) (nullable): a #GstSample or %NULL
  */
 
 GstSample *
diff --git a/ges/ges-project.c b/ges/ges-project.c
index 0a6f49fe2e..e05d76c868 100644
--- a/ges/ges-project.c
+++ b/ges/ges-project.c
@@ -732,7 +732,7 @@ ges_project_create_asset (GESProject * project, const gchar * id,
  * "asset-added" signal to get the asset when it finally gets added to
  * @project
  *
- * Returns: (transfer full): The newly created #GESAsset
+ * Returns: (transfer full) (nullable): The newly created #GESAsset or %NULL.
  */
 GESAsset *
 ges_project_create_asset_sync (GESProject * project, const gchar * id,
diff --git a/ges/ges-test-clip.c b/ges/ges-test-clip.c
index a233b9ebb2..f022f80980 100644
--- a/ges/ges-test-clip.c
+++ b/ges/ges-test-clip.c
@@ -358,8 +358,8 @@ ges_test_clip_create_track_element (GESClip * clip, GESTrackType type)
  *
  * Creates a new #GESTestClip.
  *
- * Returns: The newly created #GESTestClip, or NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created #GESTestClip,
+ * or %NULL if there was an error.
  */
 GESTestClip *
 ges_test_clip_new (void)
@@ -379,8 +379,8 @@ ges_test_clip_new (void)
  *
  * Creates a new #GESTestClip for the provided @nick.
  *
- * Returns: The newly created #GESTestClip, or NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created #GESTestClip,
+ * or %NULL if there was an error.
  */
 GESTestClip *
 ges_test_clip_new_for_nick (gchar * nick)
diff --git a/ges/ges-text-overlay-clip.c b/ges/ges-text-overlay-clip.c
index 7eb71e6927..ccaf95d5eb 100644
--- a/ges/ges-text-overlay-clip.c
+++ b/ges/ges-text-overlay-clip.c
@@ -38,7 +38,6 @@ G_DEFINE_TYPE (GESTextOverlayClip, ges_text_overlay_clip,
 #define DEFAULT_PROP_FONT_DESC "Serif 36"
 #define DEFAULT_PROP_VALIGNMENT GES_TEXT_VALIGN_BASELINE
 #define DEFAULT_PROP_HALIGNMENT GES_TEXT_HALIGN_CENTER
-#
 
 struct _GESTextOverlayClipPrivate
 {
@@ -583,8 +582,8 @@ ges_text_overlay_clip_create_track_element (GESClip * clip, GESTrackType type)
  *
  * Creates a new #GESTextOverlayClip
  *
- * Returns: The newly created #GESTextOverlayClip, or NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created
+ * #GESTextOverlayClip, or %NULL if there was an error.
  */
 GESTextOverlayClip *
 ges_text_overlay_clip_new (void)
diff --git a/ges/ges-text-overlay.c b/ges/ges-text-overlay.c
index f8569714d0..ef5cb822b4 100644
--- a/ges/ges-text-overlay.c
+++ b/ges/ges-text-overlay.c
@@ -425,8 +425,8 @@ ges_text_overlay_get_ypos (GESTextOverlay * self)
  *
  * Creates a new #GESTextOverlay.
  *
- * Returns: The newly created #GESTextOverlay or %NULL if something went
- * wrong.
+ * Returns: (transfer floating) (nullable): The newly created #GESTextOverlay or
+ * %NULL if something went wrong.
  */
 GESTextOverlay *
 ges_text_overlay_new (void)
diff --git a/ges/ges-timeline-element.c b/ges/ges-timeline-element.c
index 98cb2d5d58..e03f1f0af6 100644
--- a/ges/ges-timeline-element.c
+++ b/ges/ges-timeline-element.c
@@ -553,8 +553,8 @@ had_parent:
  * Returns the parent of @self. This function increases the refcount
  * of the parent object so you should gst_object_unref() it after usage.
  *
- * Returns: (transfer full): parent of @self, this can be %NULL if @self
- *   has no parent. unref after usage.
+ * Returns: (transfer full) (nullable): parent of @self, this can be %NULL if
+ * @self has no parent. unref after usage.
  */
 GESTimelineElement *
 ges_timeline_element_get_parent (GESTimelineElement * self)
@@ -629,8 +629,8 @@ had_timeline:
  * Returns the timeline of @self. This function increases the refcount
  * of the timeline so you should gst_object_unref() it after usage.
  *
- * Returns: (transfer full): timeline of @self, this can be %NULL if @self
- *   has no timeline. unref after usage.
+ * Returns: (transfer full) (nullable): timeline of @self, this can be %NULL if
+ * @self has no timeline. unref after usage.
  */
 GESTimeline *
 ges_timeline_element_get_timeline (GESTimelineElement * self)
diff --git a/ges/ges-timeline.c b/ges/ges-timeline.c
index a29be15698..e93718ac79 100644
--- a/ges/ges-timeline.c
+++ b/ges/ges-timeline.c
@@ -2786,7 +2786,7 @@ timeline_fill_gaps (GESTimeline * timeline)
  *
  * Creates a new empty #GESTimeline.
  *
- * Returns: The new timeline.
+ * Returns: (transfer floating): The new timeline.
  */
 
 GESTimeline *
@@ -2808,8 +2808,8 @@ ges_timeline_new (void)
  *
  * Creates a timeline from the given URI.
  *
- * Returns: A new timeline if the uri was loaded successfully, or NULL if the
- * uri could not be loaded
+ * Returns (transfer floating) (nullable): A new timeline if the uri was loaded
+ * successfully, or NULL if the uri could not be loaded.
  */
 GESTimeline *
 ges_timeline_new_from_uri (const gchar * uri, GError ** error)
@@ -2831,7 +2831,7 @@ ges_timeline_new_from_uri (const gchar * uri, GError ** error)
  *
  * Loads the contents of URI into the given timeline.
  *
- * Returns: TRUE if the timeline was loaded successfully, or FALSE if the uri
+ * Returns: %TRUE if the timeline was loaded successfully, or %FALSE if the uri
  * could not be loaded.
  */
 gboolean
@@ -2864,8 +2864,8 @@ ges_timeline_load_from_uri (GESTimeline * timeline, const gchar * uri,
  *
  * Saves the timeline to the given location
  *
- * Returns: TRUE if the timeline was successfully saved to the given location,
- * else FALSE.
+ * Returns: %TRUE if the timeline was successfully saved to the given location,
+ * else %FALSE.
  */
 gboolean
 ges_timeline_save_to_uri (GESTimeline * timeline, const gchar * uri,
@@ -2921,12 +2921,12 @@ ges_timeline_append_layer (GESTimeline * timeline)
 /**
  * ges_timeline_add_layer:
  * @timeline: a #GESTimeline
- * @layer: the #GESLayer to add
+ * @layer: (transfer full): the #GESLayer to add
  *
  * Add the layer to the timeline. The reference to the @layer will be stolen
  * by the @timeline.
  *
- * Returns: TRUE if the layer was properly added, else FALSE.
+ * Returns: %TRUE if the layer was properly added, else %FALSE.
  */
 gboolean
 ges_timeline_add_layer (GESTimeline * timeline, GESLayer * layer)
@@ -3001,7 +3001,7 @@ ges_timeline_add_layer (GESTimeline * timeline, GESLayer * layer)
  * the layer will be dropped. If you wish to use the @layer after calling this
  * method, you need to take a reference before calling.
  *
- * Returns: TRUE if the layer was properly removed, else FALSE.
+ * Returns: %TRUE if the layer was properly removed, else %FALSE.
  */
 
 gboolean
@@ -3051,12 +3051,12 @@ ges_timeline_remove_layer (GESTimeline * timeline, GESLayer * layer)
 /**
  * ges_timeline_add_track:
  * @timeline: a #GESTimeline
- * @track: the #GESTrack to add
+ * @track: (transfer full): the #GESTrack to add
  *
  * Add a track to the timeline. The reference to the track will be stolen by the
  * pipeline.
  *
- * Returns: TRUE if the track was properly added, else FALSE.
+ * Returns: %TRUE if the track was properly added, else %FALSE.
  */
 
 /* FIXME: create track elements for clips which have already been
@@ -3143,7 +3143,7 @@ ges_timeline_add_track (GESTimeline * timeline, GESTrack * track)
  * @track will be removed. If you wish to use the @track after calling this
  * function you must ensure that you have a reference to it.
  *
- * Returns: TRUE if the @track was properly removed, else FALSE.
+ * Returns: %TRUE if the @track was properly removed, else %FALSE.
  */
 
 /* FIXME: release any track elements associated with this layer. currenly this
@@ -3222,8 +3222,8 @@ ges_timeline_remove_track (GESTimeline * timeline, GESTrack * track)
  *
  * Search the #GESTrack corresponding to the given @timeline's @pad.
  *
- * Returns: (transfer none): The corresponding #GESTrack if it is found,
- * or %NULL if there is an error.
+ * Returns: (transfer none) (nullable): The corresponding #GESTrack if it is
+ * found, or %NULL if there is an error.
  */
 
 GESTrack *
@@ -3251,8 +3251,8 @@ ges_timeline_get_track_for_pad (GESTimeline * timeline, GstPad * pad)
  *
  * Search the #GstPad corresponding to the given @timeline's @track.
  *
- * Returns: (transfer none): The corresponding #GstPad if it is found,
- * or %NULL if there is an error.
+ * Returns: (transfer none) (nullable): The corresponding #GstPad if it is
+ * found, or %NULL if there is an error.
  */
 
 GstPad *
@@ -3573,7 +3573,7 @@ ges_timeline_set_snapping_distance (GESTimeline * timeline,
  *
  * Gets a #GESTimelineElement contained in the timeline
  *
- * Returns: (transfer full): The #GESTimelineElement or %NULL if
+ * Returns: (transfer full) (nullable): The #GESTimelineElement or %NULL if
  * not found.
  */
 GESTimelineElement *
@@ -3641,7 +3641,8 @@ ges_timeline_is_empty (GESTimeline * timeline)
  *
  * Retrieve the layer with @priority as a priority
  *
- * Returns: (transfer full): A #GESLayer or %NULL if no layer with @priority was found
+ * Returns: (transfer full) (nullable): A #GESLayer or %NULL if no layer with
+ * @priority was found
  *
  * Since 1.6
  */
diff --git a/ges/ges-title-clip.c b/ges/ges-title-clip.c
index df753118ef..5d28fdc6e1 100644
--- a/ges/ges-title-clip.c
+++ b/ges/ges-title-clip.c
@@ -688,8 +688,8 @@ ges_title_clip_create_track_element (GESClip * clip, GESTrackType type)
  *
  * Creates a new #GESTitleClip
  *
- * Returns: The newly created #GESTitleClip, or NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created #GESTitleClip,
+ * or %NULL if there was an error.
  */
 GESTitleClip *
 ges_title_clip_new (void)
diff --git a/ges/ges-title-source.c b/ges/ges-title-source.c
index 85ae67e7e6..19c668d930 100644
--- a/ges/ges-title-source.c
+++ b/ges/ges-title-source.c
@@ -601,8 +601,8 @@ ges_title_source_get_ypos (GESTitleSource * source)
  *
  * Creates a new #GESTitleSource.
  *
- * Returns: The newly created #GESTitleSource, or %NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created #GESTitleSource,
+ * or %NULL if there was an error.
  */
 GESTitleSource *
 ges_title_source_new (void)
diff --git a/ges/ges-track-element.c b/ges/ges-track-element.c
index 071579bc11..cea079dbe7 100644
--- a/ges/ges-track-element.c
+++ b/ges/ges-track-element.c
@@ -853,8 +853,8 @@ _ges_track_element_get_layer_priority (GESTrackElement * element)
  *
  * Get the #GESTrack to which this object belongs.
  *
- * Returns: (transfer none): The #GESTrack to which this object belongs. Can be %NULL if it
- * is not in any track
+ * Returns: (transfer none) (nullable): The #GESTrack to which this object
+ * belongs. Can be %NULL if it is not in any track
  */
 GESTrack *
 ges_track_element_get_track (GESTrackElement * object)
@@ -1525,8 +1525,8 @@ ges_track_element_set_control_source (GESTrackElement * object,
  * Looks up the various controlled properties for that #GESTrackElement,
  * and returns the #GstControlBinding which controls @property_name.
  *
- * Returns: (transfer none): the #GstControlBinding associated with @property_name, or %NULL
- * if that property is not controlled.
+ * Returns: (transfer none) (nullable): the #GstControlBinding associated with
+ * @property_name, or %NULL if that property is not controlled.
  */
 GstControlBinding *
 ges_track_element_get_control_binding (GESTrackElement * object,
diff --git a/ges/ges-track.c b/ges/ges-track.c
index c8318bacf5..75f76450c0 100644
--- a/ges/ges-track.c
+++ b/ges/ges-track.c
@@ -711,7 +711,7 @@ ges_track_init (GESTrack * self)
  * The newly created track will steal a reference to the caps. If you wish to
  * use those caps elsewhere, you will have to take an extra reference.
  *
- * Returns: A new #GESTrack.
+ * Returns: (transfer floating): A new #GESTrack.
  */
 GESTrack *
 ges_track_new (GESTrackType type, GstCaps * caps)
@@ -1059,7 +1059,7 @@ ges_track_get_caps (GESTrack * track)
  *
  * Get the #GESTimeline this track belongs to. Can be %NULL.
  *
- * Returns: The #GESTimeline this track belongs to. Can be %NULL.
+ * Returns: (nullable): The #GESTimeline this track belongs to. Can be %NULL.
  */
 const GESTimeline *
 ges_track_get_timeline (GESTrack * track)
diff --git a/ges/ges-transition-clip.c b/ges/ges-transition-clip.c
index d157bae1d5..1a47076f1b 100644
--- a/ges/ges-transition-clip.c
+++ b/ges/ges-transition-clip.c
@@ -337,8 +337,8 @@ _create_track_element (GESClip * clip, GESTrackType type)
  *
  * Creates a new #GESTransitionClip.
  *
- * Returns: a newly created #GESTransitionClip, or %NULL if something
- * went wrong.
+ * Returns: (transfer floating) (nullable): a newly created #GESTransitionClip,
+ * or %NULL if something went wrong.
  */
 GESTransitionClip *
 ges_transition_clip_new (GESVideoStandardTransitionType vtype)
@@ -372,8 +372,8 @@ ges_transition_clip_new (GESVideoStandardTransitionType vtype)
  *
  * Creates a new #GESTransitionClip for the provided @nick.
  *
- * Returns: The newly created #GESTransitionClip, or %NULL if something
- * went wrong
+ * Returns: (transfer floating) (nullable): The newly created #GESTransitionClip,
+ * or %NULL if something went wrong
  */
 
 GESTransitionClip *
diff --git a/ges/ges-uri-asset.c b/ges/ges-uri-asset.c
index 90b3cfd6dd..99331782b6 100644
--- a/ges/ges-uri-asset.c
+++ b/ges/ges-uri-asset.c
@@ -476,7 +476,8 @@ ges_uri_clip_asset_new (const gchar * uri, GCancellable * cancellable,
  * Creates a #GESUriClipAsset for @uri syncronously. You should avoid
  * to use it in application, and rather create #GESUriClipAsset asynchronously
  *
- * Returns: (transfer none): A reference to the requested asset or %NULL if an error happend
+ * Returns: (transfer none) (nullable): A reference to the requested asset or
+ * %NULL if an error happened
  */
 GESUriClipAsset *
 ges_uri_clip_asset_request_sync (const gchar * uri, GError ** error)
diff --git a/ges/ges-uri-clip.c b/ges/ges-uri-clip.c
index 2397bde89a..96c4cd9980 100644
--- a/ges/ges-uri-clip.c
+++ b/ges/ges-uri-clip.c
@@ -517,8 +517,8 @@ ges_uri_clip_create_track_element (GESClip * clip, GESTrackType type)
  *
  * Creates a new #GESUriClip for the provided @uri.
  *
- * Returns: The newly created #GESUriClip, or NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created #GESUriClip, or
+ * %NULL if there was an error.
  */
 GESUriClip *
 ges_uri_clip_new (gchar * uri)
diff --git a/ges/ges-utils.c b/ges/ges-utils.c
index e399a3ec25..fc4eddb0a0 100644
--- a/ges/ges-utils.c
+++ b/ges/ges-utils.c
@@ -35,11 +35,11 @@ static GstElementFactory *compositor_factory = NULL;
 
 /**
  * ges_timeline_new_audio_video:
- * 
+ *
  * Creates a new #GESTimeline containing a raw audio and a
  * raw video track.
  *
- * Returns: The newly created #GESTimeline.
+ * Returns: (transfer floating): The newly created #GESTimeline.
  */
 
 GESTimeline *
diff --git a/ges/ges-video-test-source.c b/ges/ges-video-test-source.c
index b84eae4ba1..483d12ecfd 100644
--- a/ges/ges-video-test-source.c
+++ b/ges/ges-video-test-source.c
@@ -130,8 +130,8 @@ ges_video_test_source_get_pattern (GESVideoTestSource * source)
  *
  * Creates a new #GESVideoTestSource.
  *
- * Returns: The newly created #GESVideoTestSource, or %NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created
+ * #GESVideoTestSource, or %NULL if there was an error.
  */
 GESVideoTestSource *
 ges_video_test_source_new (void)
diff --git a/ges/ges-video-track.c b/ges/ges-video-track.c
index 6837a38a92..44fffc54fb 100644
--- a/ges/ges-video-track.c
+++ b/ges/ges-video-track.c
@@ -133,7 +133,7 @@ ges_video_track_class_init (GESVideoTrackClass * klass)
  * Creates a new #GESVideoTrack of type #GES_TRACK_TYPE_VIDEO and with generic
  * raw video caps ("video/x-raw");
  *
- * Returns: A new #GESTrack.
+ * Returns: (transfer floating): A new #GESTrack.
  */
 GESVideoTrack *
 ges_video_track_new (void)
diff --git a/ges/ges-video-transition.c b/ges/ges-video-transition.c
index 4ddb3805cc..f58e515e9e 100644
--- a/ges/ges-video-transition.c
+++ b/ges/ges-video-transition.c
@@ -649,8 +649,8 @@ ges_video_transition_get_transition_type (GESVideoTransition * trans)
  *
  * Creates a new #GESVideoTransition.
  *
- * Returns: The newly created #GESVideoTransition, or %NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created
+ * #GESVideoTransition, or %NULL if there was an error.
  */
 GESVideoTransition *
 ges_video_transition_new (void)
diff --git a/ges/ges-video-uri-source.c b/ges/ges-video-uri-source.c
index e9c6830f96..c3dc4ac63c 100644
--- a/ges/ges-video-uri-source.c
+++ b/ges/ges-video-uri-source.c
@@ -186,8 +186,8 @@ ges_video_uri_source_init (GESVideoUriSource * self)
  *
  * Creates a new #GESVideoUriSource for the provided @uri.
  *
- * Returns: The newly created #GESVideoUriSource, or %NULL if there was an
- * error.
+ * Returns: (transfer floating) (nullable): The newly created #GESVideoUriSource,
+ * or %NULL if there was an error.
  */
 GESVideoUriSource *
 ges_video_uri_source_new (gchar * uri)