diff --git a/src/pipewire/properties.c b/src/pipewire/properties.c
index 3de43e8e9..09571d45b 100644
--- a/src/pipewire/properties.c
+++ b/src/pipewire/properties.c
@@ -145,41 +145,64 @@ struct pw_properties *pw_properties_new_dict(const struct spa_dict *dict)
 	return &impl->this;
 }
 
-static struct pw_properties *
-properties_new_string(const char *str)
+SPA_EXPORT
+int pw_properties_update_string(struct pw_properties *props, const char *str, size_t size)
 {
-	struct properties *impl;
-	const char *state = NULL, *s = NULL;
-	size_t len;
-	int res;
+	struct properties *impl = SPA_CONTAINER_OF(props, struct properties, this);
+	struct spa_json it[2];
+	int count = 0;
 
-	impl = properties_new(16);
-	if (impl == NULL)
-		return NULL;
+	spa_json_init(&it[0], str, size);
+	if (spa_json_enter_object(&it[0], &it[1]) > 0) {
+		char key[1024], *val;
 
-	s = pw_split_walk(str, " \t\n\r", &len, &state);
-	while (s) {
-		char *val, *eq;
+		while (spa_json_get_string(&it[1], key, sizeof(key)-1)) {
+			int len;
+			const char *value;
 
-		if ((val = strndup(s, len)) == NULL)
-			goto error_errno;
+			if ((len = spa_json_next(&it[1], &value)) <= 0)
+				break;
 
-		eq = strchr(val, '=');
-		if (eq && eq != val) {
-			*eq = '\0';
-			add_func(&impl->this, val, strdup(eq+1));
-		} else {
+			if (key[0] == '#')
+				continue;
+			if (spa_json_is_null(value, len))
+				val = NULL;
+			else {
+				if (spa_json_is_container(value, len))
+					len = spa_json_container_len(&it[1], value, len);
+
+				if ((val = strndup(value, len)) == NULL)
+					return -errno;
+
+				if (spa_json_is_string(value, len))
+					spa_json_parse_string(value, len, val);
+			}
+			count += pw_properties_set(&impl->this, key, val);
 			free(val);
 		}
-		s = pw_split_walk(str, " \t\n\r", &len, &state);
-	}
-	return &impl->this;
+	} else {
+		const char *state = NULL, *s = NULL;
+		size_t len;
 
-error_errno:
-	res = -errno;
-	pw_properties_free(&impl->this);
-	errno = -res;
-	return NULL;
+		s = pw_split_walk(str, " \t\n\r", &len, &state);
+		while (s) {
+			char *val, *eq;
+
+			if (s[0] == '#')
+				continue;
+			if ((val = strndup(s, len)) == NULL)
+				return -errno;
+
+			eq = strchr(val, '=');
+			if (eq && eq != val) {
+				*eq = '\0';
+				count += pw_properties_set(&impl->this, val, eq+1);
+			}
+			free(val);
+			s = pw_split_walk(str, " \t\n\r", &len, &state);
+		}
+	}
+	return count;
 }
 
 /** Make a new properties object from the given str
@@ -197,39 +220,17 @@ struct pw_properties *
 pw_properties_new_string(const char *object)
 {
 	struct properties *impl;
-	struct spa_json it[2];
-	char key[256], *val;
 	int res;
 
-	spa_json_init(&it[0], object, strlen(object));
-	if (spa_json_enter_object(&it[0], &it[1]) < 0)
-		return properties_new_string(object);
-
 	impl = properties_new(16);
 	if (impl == NULL)
 		return NULL;
 
-	while (spa_json_get_string(&it[1], key, sizeof(key)-1)) {
-		int len;
-		const char *value;
+	if ((res = pw_properties_update_string(&impl->this, object, strlen(object))) < 0)
+		goto error;
 
-		if ((len = spa_json_next(&it[1], &value)) <= 0)
-			break;
-
-		if (spa_json_is_container(value, len))
-			len = spa_json_container_len(&it[1], value, len);
-
-		if ((val = strndup(value, len)) == NULL)
-			goto error_errno;
-
-		if (spa_json_is_string(value, len))
-			spa_json_parse_string(value, len, val);
-
-		add_func(&impl->this, strdup(key), val);
-	}
 	return &impl->this;
-error_errno:
-	res = errno;
+error:
 	pw_properties_free(&impl->this);
 	errno = -res;
 	return NULL;
diff --git a/src/pipewire/properties.h b/src/pipewire/properties.h
index 4574b1fcc..120bbf423 100644
--- a/src/pipewire/properties.h
+++ b/src/pipewire/properties.h
@@ -64,6 +64,8 @@ int pw_properties_update_keys(struct pw_properties *props,
 
 int pw_properties_update(struct pw_properties *oldprops,
 		     const struct spa_dict *dict);
+int pw_properties_update_string(struct pw_properties *props,
+		const char *str, size_t size);
 
 int pw_properties_add(struct pw_properties *oldprops,
 		     const struct spa_dict *dict);
diff --git a/src/tests/test-properties.c b/src/tests/test-properties.c
index bcbf29826..5d631e40f 100644
--- a/src/tests/test-properties.c
+++ b/src/tests/test-properties.c
@@ -317,7 +317,7 @@ static void test_new_json(void)
 	props = pw_properties_new_string("{ \"foo\": \"bar\\n\\t\", \"bar\": 1.8, \"empty\": [ \"foo\", \"bar\" ], \"\": \"gg\"");
 	spa_assert(props != NULL);
 	spa_assert(props->flags == 0);
-	spa_assert(props->dict.n_items == 4);
+	spa_assert(props->dict.n_items == 3);
 
 	spa_assert(!strcmp(pw_properties_get(props, "foo"), "bar\n\t"));
 	spa_assert(!strcmp(pw_properties_get(props, "bar"), "1.8"));