Add tensor metadata registry and keypoint detection support

- Introduce meta_registry.py for centralized metadata management
- Update region_of_interest.py and tensor.py for metadata handling
- Enhance util.py with utility functions
- Add tensor conversion tests (C++ and Python)
- Include keypoint detection sample pipeline
- Update CMakeLists.txt for new tests

Author: OskarFiedot

python/gstgva/meta_registry.py

@@ -0,0 +1,40 @@
+# ==============================================================================
+# Copyright (C) 2026 Intel Corporation
+#
+# SPDX-License-Identifier: MIT
+# ==============================================================================
+
+"""Register DLStreamerMeta metadata types (GroupMtd, KeypointMtd) with the
+GstAnalytics Python override so that the RelationMeta iterator wraps them
+into the correct Python types and isinstance() checks work.
+
+Import this module once before iterating over GstAnalytics.RelationMeta
+that may contain DLStreamerMeta metadata::
+
+    import gstgva.meta_registry          # side-effect: registers types
+    # or
+    from gstgva import meta_registry     # same effect
+"""
+
+import gi
+
+gi.require_version("GstAnalytics", "1.0")
+gi.require_version("DLStreamerMeta", "1.0")
+
+# pylint: disable=no-name-in-module
+from gi.repository import DLStreamerMeta
+from gi.overrides import GstAnalytics as _GstAnalyticsOverride
+# pylint: enable=no-name-in-module
+
+# pylint: disable=protected-access
+_GstAnalyticsOverride._wrap_mtd(
+    DLStreamerMeta,
+    'KeypointMtd',
+    DLStreamerMeta.relation_meta_get_keypoint_mtd
+)
+_GstAnalyticsOverride._wrap_mtd(
+    DLStreamerMeta,
+    'GroupMtd',
+    DLStreamerMeta.relation_meta_get_group_mtd
+)
+# pylint: enable=protected-access

python/gstgva/region_of_interest.py

@@ -22,27 +22,13 @@
 # GObject Introspection modules are dynamically generated, pylint cannot introspect them
 # pylint: disable=no-name-in-module,unused-import,wrong-import-position
 from gi.repository import GstVideo, GLib, GObject, Gst, GstAnalytics, DLStreamerMeta
-from gi.overrides import GstAnalytics as GstAnalyticsOverride
 # pylint: enable=no-name-in-module,unused-import
 
 from .tensor import Tensor
 from .util import VideoRegionOfInterestMeta, GstStructureHandle
 from .util import libgst, libgstvideo
-
-# Register custom DLStreamerMeta metadata types
-# pylint: disable=protected-access
+from . import meta_registry  # noqa: F401 — registers DLStreamerMeta types with GstAnalytics
 # pylint: enable=wrong-import-position
-GstAnalyticsOverride._wrap_mtd(
-    DLStreamerMeta,
-    'KeypointMtd',
-    DLStreamerMeta.relation_meta_get_keypoint_mtd
-)
-GstAnalyticsOverride._wrap_mtd(
-    DLStreamerMeta,
-    'GroupMtd',
-    DLStreamerMeta.relation_meta_get_group_mtd
-)
-# pylint: enable=protected-access
 
 Rect = namedtuple("Rect", "x y w h")
 
@@ -71,6 +57,7 @@ def __init__(
                 tensor = Tensor(tensor_structure)
                 if (
                     tensor.name() != "object_id"
+                    and tensor.type() != "keypoints"
                     and tensor.type() != "classification_result"
                 ):
                     self._tensors.append(tensor)
@@ -321,7 +308,7 @@ def add_tensor(self, tensor: Tensor):
             raise ValueError("RegionOfInterest:add_tensor: Invalid tensor structure")
         libgstvideo.gst_video_region_of_interest_meta_add_param(self.meta(), s)
 
-        tensor_mtd = tensor.convert_to_meta(self.__od_meta.meta)
+        tensor_mtd = tensor.convert_to_meta(self.__od_meta.meta, self.__od_meta)
         if tensor_mtd is not None:
             if not self.__od_meta.meta.set_relation(
                 GstAnalytics.RelTypes.CONTAIN, self.__od_meta.id, tensor_mtd.id