diff --git a/spa/include/spa/buffer/meta.h b/spa/include/spa/buffer/meta.h
index 1775b25a9..c9202e1b9 100644
--- a/spa/include/spa/buffer/meta.h
+++ b/spa/include/spa/buffer/meta.h
@@ -38,12 +38,12 @@ extern "C" {
  */
 enum spa_meta_type {
 	SPA_META_Invalid,
-	SPA_META_Header,
-	SPA_META_VideoCrop,
-	SPA_META_VideoDamage,
-	SPA_META_Bitmap,
-	SPA_META_Cursor,
-	SPA_META_Control,	/**< metadata contains a spa_pod_sequence
+	SPA_META_Header,	/**< struct spa_meta_header */
+	SPA_META_VideoCrop,	/**< struct spa_meta_region with cropping data */
+	SPA_META_VideoDamage,	/**< array of struct spa_meta_region with damage */
+	SPA_META_Bitmap,	/**< struct spa_meta_bitmap */
+	SPA_META_Cursor,	/**< struct spa_meta_cursor */
+	SPA_META_Control,	/**< metadata contains a spa_meta_control
 				  *  associated with the data */
 
 	SPA_META_LAST,		/**< not part of ABI/API */
@@ -91,7 +91,8 @@ struct spa_meta_region {
 
 #define spa_meta_region_is_valid(m)	((m)->region.size.width != 0 && (m)->region.size.height != 0)
 
-#define spa_meta_region_for_each(pos,meta)				\
+/** iterate all the items in a metadata */
+#define spa_meta_for_each(pos,meta)					\
 	for (pos = (__typeof(pos))spa_meta_first(meta);			\
 	    spa_meta_check(pos, meta);					\
             (pos)++)
diff --git a/spa/include/spa/buffer/type-info.h b/spa/include/spa/buffer/type-info.h
index cee813113..35594d6d3 100644
--- a/spa/include/spa/buffer/type-info.h
+++ b/spa/include/spa/buffer/type-info.h
@@ -56,19 +56,23 @@ static const struct spa_type_info spa_type_data_type[] = {
 #define SPA_TYPE_INFO_Meta			SPA_TYPE_INFO_POINTER_BASE "Meta"
 #define SPA_TYPE_INFO_META_BASE			SPA_TYPE_INFO_Meta ":"
 
+#define SPA_TYPE_INFO_META_Array		SPA_TYPE_INFO_META_BASE "Array"
+#define SPA_TYPE_INFO_META_ARRAY_BASE		SPA_TYPE_INFO_META_Array ":"
+
 #define SPA_TYPE_INFO_META_Region		SPA_TYPE_INFO_META_BASE "Region"
 #define SPA_TYPE_INFO_META_REGION_BASE		SPA_TYPE_INFO_META_Region ":"
 
-#define SPA_TYPE_INFO_META_RegionArray		SPA_TYPE_INFO_META_BASE "RegionArray"
-#define SPA_TYPE_INFO_META_REGION_ARRAY_BASE	SPA_TYPE_INFO_META_RegionArray ":"
+#define SPA_TYPE_INFO_META_ARRAY_Region		SPA_TYPE_INFO_META_ARRAY_BASE "Region"
+#define SPA_TYPE_INFO_META_ARRAY_REGION_BASE	SPA_TYPE_INFO_META_ARRAY_Region ":"
 
 static const struct spa_type_info spa_type_meta_type[] = {
 	{ SPA_META_Invalid, SPA_TYPE_Pointer, SPA_TYPE_INFO_META_BASE "Invalid", NULL },
 	{ SPA_META_Header, SPA_TYPE_Pointer, SPA_TYPE_INFO_META_BASE "Header", NULL },
 	{ SPA_META_VideoCrop, SPA_TYPE_Pointer, SPA_TYPE_INFO_META_REGION_BASE "VideoCrop", NULL },
-	{ SPA_META_VideoDamage, SPA_TYPE_Pointer, SPA_TYPE_INFO_META_REGION_ARRAY_BASE "VideoDamage", NULL },
+	{ SPA_META_VideoDamage, SPA_TYPE_Pointer, SPA_TYPE_INFO_META_ARRAY_REGION_BASE "VideoDamage", NULL },
 	{ SPA_META_Bitmap, SPA_TYPE_Pointer, SPA_TYPE_INFO_META_BASE "Bitmap", NULL },
 	{ SPA_META_Cursor, SPA_TYPE_Pointer, SPA_TYPE_INFO_META_BASE "Cursor", NULL },
+	{ SPA_META_Control, SPA_TYPE_Pointer, SPA_TYPE_INFO_META_BASE "Control", NULL },
 	{ 0, 0, NULL, NULL },
 };
 
diff --git a/spa/include/spa/debug/buffer.h b/spa/include/spa/debug/buffer.h
index 69dcbc8a8..bc769bcf4 100644
--- a/spa/include/spa/debug/buffer.h
+++ b/spa/include/spa/debug/buffer.h
@@ -75,7 +75,7 @@ static inline int spa_debug_buffer(int indent, const struct spa_buffer *buffer)
 		case SPA_META_VideoDamage:
 		{
 			struct spa_meta_region *h;
-			spa_meta_region_for_each(h, m) {
+			spa_meta_for_each(h, m) {
 				spa_debug("%*s" "    struct spa_meta_region:", indent, "");
 				spa_debug("%*s" "      x:      %d", indent, "", h->region.position.x);
 				spa_debug("%*s" "      y:      %d", indent, "", h->region.position.y);
diff --git a/spa/include/spa/monitor/device.h b/spa/include/spa/monitor/device.h
index e2741d157..a946c9d25 100644
--- a/spa/include/spa/monitor/device.h
+++ b/spa/include/spa/monitor/device.h
@@ -37,11 +37,19 @@ extern "C" {
 /**
  * spa_device:
  *
- * The device interface.
+ * The device interface can be used to monitor all kinds of devices
+ * and create objects as a result. Objects a typically other
+ * Devices or Nodes.
+ *
  */
 #define SPA_VERSION_DEVICE 0
 struct spa_device { struct spa_interface iface; };
 
+/**
+ * Information about the device and parameters it supports
+ *
+ * This information is part of the info event on a device.
+ */
 struct spa_device_info {
 #define SPA_VERSION_DEVICE_INFO 0
 	uint32_t version;
@@ -51,25 +59,30 @@ struct spa_device_info {
 #define SPA_DEVICE_CHANGE_MASK_PARAMS		(1u<<2)
 	uint64_t change_mask;
 	uint64_t flags;
-	const struct spa_dict *props;
-	struct spa_param_info *params;
-	uint32_t n_params;
+	const struct spa_dict *props;		/**< device properties */
+	struct spa_param_info *params;		/**< supported parameters */
+	uint32_t n_params;			/**< number of elements in params */
 };
 
 #define SPA_DEVICE_INFO_INIT()	(struct spa_device_info){ SPA_VERSION_DEVICE_INFO, }
 
+/**
+ * Information about a device object
+ *
+ * This information is part of the object_info event on the device.
+ */
 struct spa_device_object_info {
 #define SPA_VERSION_DEVICE_OBJECT_INFO 0
 	uint32_t version;
 
-	uint32_t type;
-	const char *factory_name;
+	uint32_t type;				/**< the object type managed by this device */
+	const char *factory_name;		/**< a factory name that implements the object */
 
 #define SPA_DEVICE_OBJECT_CHANGE_MASK_FLAGS	(1u<<0)
 #define SPA_DEVICE_OBJECT_CHANGE_MASK_PROPS	(1u<<1)
 	uint64_t change_mask;
 	uint64_t flags;
-	const struct spa_dict *props;
+	const struct spa_dict *props;		/**< extra object properties */
 };
 
 #define SPA_DEVICE_OBJECT_INFO_INIT()	(struct spa_device_object_info){ SPA_VERSION_DEVICE_OBJECT_INFO, }
@@ -134,7 +147,7 @@ struct spa_device_methods {
 	 * the device.
 	 *
 	 * Setting the events will trigger the info event and an
-	 * object_info event for each managed node on the new
+	 * object_info event for each managed object on the new
 	 * listener.
 	 *
 	 * \param device a #spa_device
diff --git a/src/examples/export-sink.c b/src/examples/export-sink.c
index 781e6d70a..d2e626d67 100644
--- a/src/examples/export-sink.c
+++ b/src/examples/export-sink.c
@@ -387,7 +387,7 @@ static int do_render(struct spa_loop *loop, bool async, uint32_t seq,
 	}
 
 	if ((m = spa_buffer_find_meta(buf, SPA_META_VideoDamage))) {
-		spa_meta_region_for_each(r, m) {
+		spa_meta_for_each(r, m) {
 			if (!spa_meta_region_is_valid(r))
 				break;
 			if (memcmp(&r->region, &d->region, sizeof(struct spa_region)) == 0)
diff --git a/src/modules/module-protocol-native/v0/typemap.h b/src/modules/module-protocol-native/v0/typemap.h
index 6620fbd44..b8ea4704b 100644
--- a/src/modules/module-protocol-native/v0/typemap.h
+++ b/src/modules/module-protocol-native/v0/typemap.h
@@ -44,7 +44,7 @@ const struct type_info {
 	{ "Spa:Enum:ParamId:Meta", SPA_TYPE_INFO_PARAM_ID_BASE "Meta", SPA_PARAM_Meta, },
 	{ "Spa:Pointer:Meta:Header", SPA_TYPE_INFO_META_BASE "Header", SPA_META_Header, },
 	{ "Spa:Pointer:Meta:VideoCrop", SPA_TYPE_INFO_META_REGION_BASE "VideoCrop", SPA_META_VideoCrop, },
-	{ "Spa:Pointer:Meta:VideoDamage", SPA_TYPE_INFO_META_REGION_ARRAY_BASE "VideoDamage", SPA_META_VideoDamage, },
+	{ "Spa:Pointer:Meta:VideoDamage", SPA_TYPE_INFO_META_ARRAY_REGION_BASE "VideoDamage", SPA_META_VideoDamage, },
 	{ "Spa:Pointer:Meta:Bitmap", SPA_TYPE_INFO_META_BASE "Bitmap", SPA_META_Bitmap, },
 	{ "Spa:Pointer:Meta:Cursor", SPA_TYPE_INFO_META_BASE "Cursor", SPA_META_Cursor, },
 	{ "Spa:Enum:DataType:MemPtr", SPA_TYPE_INFO_DATA_BASE "MemPtr", SPA_DATA_MemPtr, },