onnx: Port SSD detector to C

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6001>

8 files changed, 264 insertions, 380 deletions

diff --git a/subprojects/gst-plugins-bad/ext/onnx/decoders/gstobjectdetectorutils.cpp b/subprojects/gst-plugins-bad/ext/onnx/decoders/gstobjectdetectorutils.cpp
deleted file mode 100644
index dbd4b30843..0000000000
--- a/subprojects/gst-plugins-bad/ext/onnx/decoders/gstobjectdetectorutils.cpp
+++ /dev/null
@@ -1,228 +0,0 @@
-/*
- * GStreamer gstreamer-objectdetectorutils
- * Copyright (C) 2023 Collabora Ltd
- *
- * gstobjectdetectorutils.cpp
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
- * Boston, MA 02110-1301, USA.
- */
-
-#include "gstobjectdetectorutils.h"
-
-#include <gio/gio.h>
-
-
-char **
-read_labels (const char * labels_file)
-{
-  GPtrArray *array;
-  GFile *file = g_file_new_for_path (labels_file);
-  GFileInputStream *file_stream;
-  GDataInputStream *data_stream;
-  GError *error = NULL;
-  gchar *line;
-
-  file_stream = g_file_read (file, NULL, &error);
-  g_object_unref (file);
-  if (!file_stream) {
-    GST_WARNING ("Could not open file %s: %s\n", labels_file,
-		 error->message);
-    g_clear_error (&error);
-    return NULL;
-  }
-
-  data_stream = g_data_input_stream_new (G_INPUT_STREAM (file_stream));
-  g_object_unref (file_stream);
-
-  array = g_ptr_array_new();
-
-  while ((line = g_data_input_stream_read_line (data_stream, NULL, NULL,
-						&error)))
-    g_ptr_array_add (array, line);
-
-  g_object_unref (data_stream);
-
-  if (error) {
-    GST_WARNING ("Could not open file %s: %s", labels_file, error->message);
-    g_ptr_array_free (array, TRUE);
-    g_clear_error (&error);
-    return NULL;
-  }
-
-  if (array->len == 0) {
-    g_ptr_array_free (array, TRUE);
-    return NULL;
-  }
-
-  g_ptr_array_add (array, NULL);
-
-  return (char **) g_ptr_array_free (array, FALSE);
-}
-
-
-GstMlBoundingBox::GstMlBoundingBox (std::string lbl, float score, float _x0,
-    float _y0, float _width, float _height):
-label (lbl),
-score (score),
-x0 (_x0),
-y0 (_y0),
-width (_width),
-height (_height)
-{
-}
-
-GstMlBoundingBox::GstMlBoundingBox ():
-GstMlBoundingBox ("", 0.0f, 0.0f, 0.0f, 0.0f, 0.0f)
-{
-}
-
-namespace GstObjectDetectorUtils
-{
-
-  GstObjectDetectorUtils::GstObjectDetectorUtils ()
-  {
-  }
-
-
-  std::vector < GstMlBoundingBox > GstObjectDetectorUtils::run (int32_t w,
-      int32_t h, GstTensorMeta * tmeta, gchar **labels,
-      float scoreThreshold)
-  {
-
-    auto classIndex = gst_tensor_meta_get_index_from_id (tmeta,
-        g_quark_from_static_string (GST_MODEL_OBJECT_DETECTOR_CLASSES));
-    if (classIndex == GST_TENSOR_MISSING_ID) {
-      GST_ERROR ("Missing class tensor id");
-      return std::vector < GstMlBoundingBox > ();
-    }
-    auto type = tmeta->tensor[classIndex].type;
-    return (type == GST_TENSOR_TYPE_FLOAT32) ?
-        doRun < float >(w, h, tmeta, labels, scoreThreshold)
-    : doRun < int >(w, h, tmeta, labels, scoreThreshold);
-  }
-
-  template < typename T > std::vector < GstMlBoundingBox >
-      GstObjectDetectorUtils::doRun (int32_t w, int32_t h,
-      GstTensorMeta * tmeta, char **labels, float scoreThreshold)
-  {
-    std::vector < GstMlBoundingBox > boundingBoxes;
-    GstMapInfo map_info[GstObjectDetectorMaxNodes];
-    GstMemory *memory[GstObjectDetectorMaxNodes] = { NULL };
-    gint index;
-    T *numDetections = nullptr, *bboxes = nullptr, *scores =
-        nullptr, *labelIndex = nullptr;
-
-    // number of detections
-    index = gst_tensor_meta_get_index_from_id (tmeta,
-        g_quark_from_static_string (GST_MODEL_OBJECT_DETECTOR_NUM_DETECTIONS));
-    if (index == GST_TENSOR_MISSING_ID) {
-      GST_WARNING ("Missing tensor data for tensor index %d", index);
-      goto cleanup;
-    }
-    memory[index] = gst_buffer_peek_memory (tmeta->tensor[index].data, 0);
-    if (!memory[index]) {
-      GST_WARNING ("Missing tensor data for tensor index %d", index);
-      goto cleanup;
-    }
-    if (!gst_memory_map (memory[index], map_info + index, GST_MAP_READ)) {
-      GST_WARNING ("Failed to map tensor memory for index %d", index);
-      goto cleanup;
-    }
-    numDetections = (T *) map_info[index].data;
-
-    // bounding boxes
-    index =
-        gst_tensor_meta_get_index_from_id (tmeta,
-					   g_quark_from_static_string(GST_MODEL_OBJECT_DETECTOR_BOXES));
-    if (index == GST_TENSOR_MISSING_ID) {
-      GST_WARNING ("Missing tensor data for tensor index %d", index);
-      goto cleanup;
-    }
-    memory[index] = gst_buffer_peek_memory (tmeta->tensor[index].data, 0);
-    if (!memory[index]) {
-      GST_WARNING ("Failed to map tensor memory for index %d", index);
-      goto cleanup;
-    }
-    if (!gst_memory_map (memory[index], map_info + index, GST_MAP_READ)) {
-      GST_ERROR ("Failed to map GstMemory");
-      goto cleanup;
-    }
-    bboxes = (T *) map_info[index].data;
-
-    // scores
-    index =
-        gst_tensor_meta_get_index_from_id (tmeta,
-        g_quark_from_static_string (GST_MODEL_OBJECT_DETECTOR_SCORES));
-    if (index == GST_TENSOR_MISSING_ID) {
-      GST_ERROR ("Missing scores tensor id");
-      goto cleanup;
-    }
-    memory[index] = gst_buffer_peek_memory (tmeta->tensor[index].data, 0);
-    if (!memory[index]) {
-      GST_WARNING ("Missing tensor data for tensor index %d", index);
-      goto cleanup;
-    }
-    if (!gst_memory_map (memory[index], map_info + index, GST_MAP_READ)) {
-      GST_ERROR ("Failed to map GstMemory");
-      goto cleanup;
-    }
-    scores = (T *) map_info[index].data;
-
-    // optional label
-    labelIndex = nullptr;
-    index =
-        gst_tensor_meta_get_index_from_id (tmeta,
-        g_quark_from_static_string (GST_MODEL_OBJECT_DETECTOR_CLASSES));
-    if (index != GST_TENSOR_MISSING_ID) {
-      memory[index] = gst_buffer_peek_memory (tmeta->tensor[index].data, 0);
-      if (!memory[index]) {
-        GST_WARNING ("Missing tensor data for tensor index %d", index);
-        goto cleanup;
-      }
-      if (!gst_memory_map (memory[index], map_info + index, GST_MAP_READ)) {
-        GST_ERROR ("Failed to map GstMemory");
-        goto cleanup;
-      }
-      labelIndex = (T *) map_info[index].data;
-    }
-
-    for (int i = 0; i < numDetections[0]; ++i) {
-      if (scores[i] > scoreThreshold) {
-        std::string label = "";
-
-        if (labels && labelIndex)
-          label = labels[(int)labelIndex[i] - 1];
-        auto score = scores[i];
-        auto y0 = bboxes[i * 4] * h;
-        auto x0 = bboxes[i * 4 + 1] * w;
-        auto bheight = bboxes[i * 4 + 2] * h - y0;
-        auto bwidth = bboxes[i * 4 + 3] * w - x0;
-        boundingBoxes.push_back (GstMlBoundingBox (label, score, x0, y0, bwidth,
-                bheight));
-      }
-    }
-
-  cleanup:
-    for (int i = 0; i < GstObjectDetectorMaxNodes; ++i) {
-      if (memory[i])
-        gst_memory_unmap (memory[i], map_info + i);
-
-    }
-
-    return boundingBoxes;
-  }
-
-}
diff --git a/subprojects/gst-plugins-bad/ext/onnx/decoders/gstobjectdetectorutils.h b/subprojects/gst-plugins-bad/ext/onnx/decoders/gstobjectdetectorutils.h
deleted file mode 100644
index 2e7a83995a..0000000000
--- a/subprojects/gst-plugins-bad/ext/onnx/decoders/gstobjectdetectorutils.h
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
- * GStreamer gstreamer-objectdetectorutils
- * Copyright (C) 2023 Collabora Ltd
- *
- * gstobjectdetectorutils.h
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
- * Boston, MA 02110-1301, USA.
- */
-#ifndef __GST_OBJECT_DETECTOR_UTILS_H__
-#define __GST_OBJECT_DETECTOR_UTILS_H__
-
-#include <gst/gst.h>
-#include <string>
-#include <vector>
-
-#include "gstml.h"
-#include "tensor/gsttensormeta.h"
-
-char ** read_labels (const char * labels_file);
-
-/* Object detection tensor id strings */
-#define GST_MODEL_OBJECT_DETECTOR_BOXES "Gst.Model.ObjectDetector.Boxes"
-#define GST_MODEL_OBJECT_DETECTOR_SCORES "Gst.Model.ObjectDetector.Scores"
-#define GST_MODEL_OBJECT_DETECTOR_NUM_DETECTIONS "Gst.Model.ObjectDetector.NumDetections"
-#define GST_MODEL_OBJECT_DETECTOR_CLASSES "Gst.Model.ObjectDetector.Classes"
-
-
-/**
- * GstMlBoundingBox:
- *
- * @label label
- * @score detection confidence
- * @x0 top left hand x coordinate
- * @y0 top left hand y coordinate
- * @width width
- * @height height
- *
- * Since: 1.20
- */
-struct GstMlBoundingBox {
-	GstMlBoundingBox(std::string lbl, float score, float _x0, float _y0,
-			float _width, float _height);
-	GstMlBoundingBox();
-	std::string label;
-	float score;
-	float x0;
-	float y0;
-	float width;
-	float height;
-};
-
-namespace GstObjectDetectorUtils {
-  const int GstObjectDetectorMaxNodes = 4;
-  class GstObjectDetectorUtils {
-  public:
-	 GstObjectDetectorUtils(void);
-    ~GstObjectDetectorUtils(void) = default;
-    std::vector < GstMlBoundingBox > run(int32_t w, int32_t h,
-    									GstTensorMeta *tmeta,
-                                          char **labels,
-                                          float scoreThreshold);
-  private:
-    template < typename T > std::vector < GstMlBoundingBox >
-    doRun(int32_t w, int32_t h,
-    		GstTensorMeta *tmeta, char **labels,
-            float scoreThreshold);
-  };
-}
-
-#endif                          /* __GST_OBJECT_DETECTOR_UTILS_H__ */
diff --git a/subprojects/gst-plugins-bad/ext/onnx/decoders/gstssdobjectdetector.cpp b/subprojects/gst-plugins-bad/ext/onnx/decoders/gstssdobjectdetector.c
index 5c69579323..f89ab28f4f 100644
--- a/subprojects/gst-plugins-bad/ext/onnx/decoders/gstssdobjectdetector.cpp
+++ b/subprojects/gst-plugins-bad/ext/onnx/decoders/gstssdobjectdetector.c
@@ -44,19 +44,23 @@
 #include "config.h"
 #endif
 
-
 #include "gstssdobjectdetector.h"
-#include "gstobjectdetectorutils.h"
+
+#include <gio/gio.h>
 
 #include <gst/gst.h>
 #include <gst/video/video.h>
-
 #include <gst/analytics/analytics.h>
 #include "tensor/gsttensormeta.h"
 
+/* Object detection tensor id strings */
+#define GST_MODEL_OBJECT_DETECTOR_BOXES "Gst.Model.ObjectDetector.Boxes"
+#define GST_MODEL_OBJECT_DETECTOR_SCORES "Gst.Model.ObjectDetector.Scores"
+#define GST_MODEL_OBJECT_DETECTOR_NUM_DETECTIONS "Gst.Model.ObjectDetector.NumDetections"
+#define GST_MODEL_OBJECT_DETECTOR_CLASSES "Gst.Model.ObjectDetector.Classes"
+
 GST_DEBUG_CATEGORY_STATIC (ssd_object_detector_debug);
 #define GST_CAT_DEFAULT ssd_object_detector_debug
-#define GST_ODUTILS_MEMBER( self ) ((GstObjectDetectorUtils::GstObjectDetectorUtils *) (self->odutils))
 GST_ELEMENT_REGISTER_DEFINE (ssd_object_detector, "ssdobjectdetector",
     GST_RANK_PRIMARY, GST_TYPE_SSD_OBJECT_DETECTOR);
 
@@ -68,7 +72,7 @@ enum
   PROP_SCORE_THRESHOLD,
 };
 
-#define GST_SSD_OBJECT_DETECTOR_DEFAULT_SCORE_THRESHOLD       0.3f  /* 0 to 1 */
+#define GST_SSD_OBJECT_DETECTOR_DEFAULT_SCORE_THRESHOLD       0.3f      /* 0 to 1 */
 
 static GstStaticPadTemplate gst_ssd_object_detector_src_template =
 GST_STATIC_PAD_TEMPLATE ("src",
@@ -97,7 +101,8 @@ static gboolean
 gst_ssd_object_detector_set_caps (GstBaseTransform * trans, GstCaps * incaps,
     GstCaps * outcaps);
 
-G_DEFINE_TYPE (GstSsdObjectDetector, gst_ssd_object_detector, GST_TYPE_BASE_TRANSFORM);
+G_DEFINE_TYPE (GstSsdObjectDetector, gst_ssd_object_detector,
+    GST_TYPE_BASE_TRANSFORM);
 
 static void
 gst_ssd_object_detector_class_init (GstSsdObjectDetectorClass * klass)
@@ -135,7 +140,8 @@ gst_ssd_object_detector_class_init (GstSsdObjectDetectorClass * klass)
       g_param_spec_float ("score-threshold",
           "Score threshold",
           "Threshold for deciding when to remove boxes based on score",
-          0.0, 1.0, GST_SSD_OBJECT_DETECTOR_DEFAULT_SCORE_THRESHOLD, (GParamFlags)
+          0.0, 1.0, GST_SSD_OBJECT_DETECTOR_DEFAULT_SCORE_THRESHOLD,
+          (GParamFlags)
           (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)));
 
   gst_element_class_set_static_metadata (element_class, "objectdetector",
@@ -155,7 +161,6 @@ gst_ssd_object_detector_class_init (GstSsdObjectDetectorClass * klass)
 static void
 gst_ssd_object_detector_init (GstSsdObjectDetector * self)
 {
-  self->odutils = new GstObjectDetectorUtils::GstObjectDetectorUtils ();
 }
 
 static void
@@ -164,12 +169,58 @@ gst_ssd_object_detector_finalize (GObject * object)
   GstSsdObjectDetector *self = GST_SSD_OBJECT_DETECTOR (object);
 
   g_free (self->label_file);
-  g_strfreev (self->labels);
-  delete GST_ODUTILS_MEMBER (self);
+  g_clear_pointer (&self->labels, g_array_unref);
 
   G_OBJECT_CLASS (gst_ssd_object_detector_parent_class)->finalize (object);
 }
 
+static GArray *
+read_labels (const char *labels_file)
+{
+  GArray *array;
+  GFile *file = g_file_new_for_path (labels_file);
+  GFileInputStream *file_stream;
+  GDataInputStream *data_stream;
+  GError *error = NULL;
+  gchar *line;
+
+  file_stream = g_file_read (file, NULL, &error);
+  g_object_unref (file);
+  if (!file_stream) {
+    GST_WARNING ("Could not open file %s: %s\n", labels_file, error->message);
+    g_clear_error (&error);
+    return NULL;
+  }
+
+  data_stream = g_data_input_stream_new (G_INPUT_STREAM (file_stream));
+  g_object_unref (file_stream);
+
+  array = g_array_new (FALSE, FALSE, sizeof (GQuark));
+
+  while ((line = g_data_input_stream_read_line (data_stream, NULL, NULL,
+              &error))) {
+    GQuark label = g_quark_from_string (line);
+    g_array_append_val (array, label);
+    g_free (line);
+  }
+
+  g_object_unref (data_stream);
+
+  if (error) {
+    GST_WARNING ("Could not open file %s: %s", labels_file, error->message);
+    g_array_free (array, TRUE);
+    g_clear_error (&error);
+    return NULL;
+  }
+
+  if (array->len == 0) {
+    g_array_free (array, TRUE);
+    return NULL;
+  }
+
+  return array;
+}
+
 static void
 gst_ssd_object_detector_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
@@ -179,21 +230,21 @@ gst_ssd_object_detector_set_property (GObject * object, guint prop_id,
 
   switch (prop_id) {
     case PROP_LABEL_FILE:
-      {
-	gchar **labels;
-
-	filename = g_value_get_string (value);
-	labels = read_labels (filename);
-
-	if (labels) {
-	  g_free (self->label_file);
-	  self->label_file = g_strdup (filename);
-	  g_strfreev (self->labels);
-	  self->labels = labels;
-	} else {
-	  GST_WARNING_OBJECT (self, "Label file '%s' not found!", filename);
-	}
+    {
+      GArray *labels;
+
+      filename = g_value_get_string (value);
+      labels = read_labels (filename);
+
+      if (labels) {
+        g_free (self->label_file);
+        self->label_file = g_strdup (filename);
+        g_clear_pointer (&self->labels, g_array_unref);
+        self->labels = labels;
+      } else {
+        GST_WARNING_OBJECT (self, "Label file '%s' not found!", filename);
       }
+    }
       break;
     case PROP_SCORE_THRESHOLD:
       GST_OBJECT_LOCK (self);
@@ -259,7 +310,8 @@ gst_ssd_object_detector_get_tensor_meta (GstSsdObjectDetector * object_detector,
     gint clasesIndex = gst_tensor_meta_get_index_from_id (tensor_meta,
         g_quark_from_static_string (GST_MODEL_OBJECT_DETECTOR_CLASSES));
 
-    if (boxesIndex == GST_TENSOR_MISSING_ID || scoresIndex == GST_TENSOR_MISSING_ID
+    if (boxesIndex == GST_TENSOR_MISSING_ID
+        || scoresIndex == GST_TENSOR_MISSING_ID
         || numDetectionsIndex == GST_TENSOR_MISSING_ID)
       continue;
 
@@ -300,13 +352,175 @@ gst_ssd_object_detector_transform_ip (GstBaseTransform * trans, GstBuffer * buf)
   return GST_FLOW_OK;
 }
 
+#define DEFINE_GET_FUNC(TYPE, MAX)                                      \
+  static gboolean							\
+  get_ ## TYPE ## _at_index (GstTensor *tensor, GstMapInfo *map,        \
+      guint index, TYPE * out)                                          \
+  {									\
+    switch (tensor->type) {                                             \
+  case GST_TENSOR_TYPE_FLOAT32: {					\
+    float *f = (float *) map->data;                                     \
+    if (sizeof(*f) * (index + 1) > map->size)				\
+      return FALSE;							\
+    *out = f[index];							\
+    break;                                                              \
+  }									\
+  case GST_TENSOR_TYPE_UINT32: {					\
+    guint32 *u = (guint32 *) map->data;                                 \
+    if (sizeof(*u) * (index + 1) > map->size)				\
+      return FALSE;							\
+    *out = u[index];							\
+    break;                                                              \
+  }									\
+  default:								\
+    GST_ERROR ("Only float32 and int32 tensors are understood");	\
+    return FALSE;							\
+  }									\
+  return TRUE;								\
+  }
+
+DEFINE_GET_FUNC (guint32, UINT32_MAX)
+    DEFINE_GET_FUNC (float, FLOAT_MAX)
+#undef DEFINE_GET_FUNC
+     static void
+         extract_bounding_boxes (GstSsdObjectDetector * self, gsize w, gsize h,
+    GstAnalyticsRelationMeta * rmeta, GstTensorMeta * tmeta)
+{
+  gint classes_index;
+  gint boxes_index;
+  gint scores_index;
+  gint numdetect_index;
+
+  GstMapInfo boxes_map = GST_MAP_INFO_INIT;
+  GstMapInfo numdetect_map = GST_MAP_INFO_INIT;
+  GstMapInfo scores_map = GST_MAP_INFO_INIT;
+  GstMapInfo classes_map = GST_MAP_INFO_INIT;
+
+  guint num_detections = 0;
+
+  classes_index = gst_tensor_meta_get_index_from_id (tmeta,
+      g_quark_from_static_string (GST_MODEL_OBJECT_DETECTOR_CLASSES));
+  numdetect_index = gst_tensor_meta_get_index_from_id (tmeta,
+      g_quark_from_static_string (GST_MODEL_OBJECT_DETECTOR_NUM_DETECTIONS));
+  scores_index = gst_tensor_meta_get_index_from_id (tmeta,
+      g_quark_from_static_string (GST_MODEL_OBJECT_DETECTOR_SCORES));
+  boxes_index = gst_tensor_meta_get_index_from_id (tmeta,
+      g_quark_from_static_string (GST_MODEL_OBJECT_DETECTOR_BOXES));
+
+  if (numdetect_index == GST_TENSOR_MISSING_ID
+      || scores_index == GST_TENSOR_MISSING_ID
+      || numdetect_index == GST_TENSOR_MISSING_ID) {
+    GST_WARNING ("Missing tensor data expected for SSD model");
+    return;
+  }
+
+  if (!gst_buffer_map (tmeta->tensor[numdetect_index].data, &numdetect_map,
+          GST_MAP_READ)) {
+    GST_ERROR_OBJECT (self, "Failed to map tensor memory for index %d",
+        numdetect_index);
+    goto cleanup;
+  }
+
+  if (!gst_buffer_map (tmeta->tensor[boxes_index].data, &boxes_map,
+          GST_MAP_READ)) {
+    GST_ERROR_OBJECT (self, "Failed to map tensor memory for index %d",
+        boxes_index);
+    goto cleanup;
+  }
+
+  if (!gst_buffer_map (tmeta->tensor[scores_index].data, &scores_map,
+          GST_MAP_READ)) {
+    GST_ERROR_OBJECT (self, "Failed to map tensor memory for index %d",
+        scores_index);
+    goto cleanup;
+  }
+
+  if (classes_index != GST_TENSOR_MISSING_ID &&
+      !gst_buffer_map (tmeta->tensor[classes_index].data, &classes_map,
+          GST_MAP_READ)) {
+    GST_DEBUG_OBJECT (self, "Failed to map tensor memory for index %d",
+        classes_index);
+  }
+
+
+  if (!get_guint32_at_index (&tmeta->tensor[numdetect_index], &numdetect_map,
+          0, &num_detections)) {
+    GST_ERROR_OBJECT (self, "Failed to get the number of detections");
+    goto cleanup;
+  }
+
+
+  GST_LOG_OBJECT (self, "Model claims %d detections", num_detections);
+
+  for (int i = 0; i < num_detections; i++) {
+    float score;
+    float x, y, bwidth, bheight;
+    gint x_i, y_i, bwidth_i, bheight_i;
+    guint32 bclass;
+    GQuark label = 0;
+    GstAnalyticsODMtd odmtd;
+
+    if (!get_float_at_index (&tmeta->tensor[numdetect_index], &scores_map,
+            i, &score))
+      continue;
+
+    GST_LOG_OBJECT (self, "Detection %u score is %f", i, score);
+    if (score < self->score_threshold)
+      continue;
+
+    if (!get_float_at_index (&tmeta->tensor[boxes_index], &boxes_map,
+            i * 4, &y))
+      continue;
+    if (!get_float_at_index (&tmeta->tensor[boxes_index], &boxes_map,
+            i * 4 + 1, &x))
+      continue;
+    if (!get_float_at_index (&tmeta->tensor[boxes_index], &boxes_map,
+            i * 4 + 2, &bheight))
+      continue;
+    if (!get_float_at_index (&tmeta->tensor[boxes_index], &boxes_map,
+            i * 4 + 3, &bwidth))
+      continue;
+
+    if (self->labels && classes_map.memory &&
+        get_guint32_at_index (&tmeta->tensor[classes_index], &classes_map,
+            i, &bclass)) {
+      if (bclass < self->labels->len)
+        label = g_array_index (self->labels, GQuark, bclass);
+    }
+
+    x_i = x * w;
+    y_i = y * h;
+    bheight_i = (bheight * h) - y_i;
+    bwidth_i = (bwidth * w) - x_i;
+
+    if (gst_analytics_relation_meta_add_od_mtd (rmeta, label,
+            x_i, y_i, bwidth_i, bheight_i, score, &odmtd))
+      GST_DEBUG_OBJECT (self,
+          "Object detected with label : %s, score: %f, bound box: %dx%d at (%d,%d)",
+          g_quark_to_string (label), score, bwidth_i, bheight_i, x_i, y_i);
+    else
+      GST_WARNING_OBJECT (self, "Could not add detection to meta");
+  }
+
+cleanup:
+
+  if (numdetect_map.memory)
+    gst_buffer_unmap (tmeta->tensor[numdetect_index].data, &numdetect_map);
+  if (classes_map.memory)
+    gst_buffer_unmap (tmeta->tensor[classes_index].data, &classes_map);
+  if (scores_map.memory)
+    gst_buffer_unmap (tmeta->tensor[scores_index].data, &scores_map);
+  if (boxes_map.memory)
+    gst_buffer_unmap (tmeta->tensor[boxes_index].data, &boxes_map);
+}
+
+
 static gboolean
 gst_ssd_object_detector_process (GstBaseTransform * trans, GstBuffer * buf)
 {
-  GstTensorMeta *tmeta = NULL;
-  GstAnalyticsODMtd odmtd;
-  GstAnalyticsRelationMeta *rmeta;
   GstSsdObjectDetector *self = GST_SSD_OBJECT_DETECTOR (trans);
+  GstTensorMeta *tmeta;
+  GstAnalyticsRelationMeta *rmeta;
 
   // get all tensor metas
   tmeta = gst_ssd_object_detector_get_tensor_meta (self, buf);
@@ -315,25 +529,11 @@ gst_ssd_object_detector_process (GstBaseTransform * trans, GstBuffer * buf)
     return TRUE;
   } else {
     rmeta = gst_buffer_add_analytics_relation_meta (buf);
-    g_return_val_if_fail (rmeta != NULL, FALSE);
+    g_assert (rmeta);
   }
 
-  std::vector < GstMlBoundingBox > boxes =
-      GST_ODUTILS_MEMBER (self)->run (self->video_info.width,
-      self->video_info.height, tmeta, self->labels,
-      self->score_threshold);
-
-  for (auto & b:boxes) {
-    if (gst_analytics_relation_meta_add_od_mtd (rmeta,
-        g_quark_from_string(b.label.c_str ()), b.x0, b.y0, b.width, b.height,
-        b.score, &odmtd)) {
-      GST_DEBUG_OBJECT (self,
-        "Object detected with label : %s, score: %f, bound box: (%f,%f,%f,%f)",
-        b.label.c_str (), b.score, b.x0, b.y0, b.x0 + b.width, b.y0 + b.height);
-    } else {
-      GST_ERROR_OBJECT (self, "Failed to add object detection analytics-meta");
-    }
-  }
+  extract_bounding_boxes (self, self->video_info.width,
+      self->video_info.height, rmeta, tmeta);
 
   return TRUE;
 }
diff --git a/subprojects/gst-plugins-bad/ext/onnx/decoders/gstssdobjectdetector.h b/subprojects/gst-plugins-bad/ext/onnx/decoders/gstssdobjectdetector.h
index b101650ba4..9bc89aa85a 100644
--- a/subprojects/gst-plugins-bad/ext/onnx/decoders/gstssdobjectdetector.h
+++ b/subprojects/gst-plugins-bad/ext/onnx/decoders/gstssdobjectdetector.h
@@ -37,14 +37,11 @@ G_DECLARE_FINAL_TYPE (GstSsdObjectDetector, gst_ssd_object_detector, GST, SSD_OB
 #define GST_SSD_OBJECT_DETECTOR_META_FIELD_LABEL "label"
 #define GST_SSD_OBJECT_DETECTOR_META_FIELD_SCORE "score"
 
-/**
+/*
  * GstSsdObjectDetector:
  *
  * @label_file label file
  * @score_threshold score threshold
- * @confidence_threshold confidence threshold
- * @iou_threhsold iou threshold
- * @od_ptr opaque pointer to GstOd object detection implementation
  *
  * Since: 1.20
  */
@@ -52,11 +49,8 @@ struct _GstSsdObjectDetector
 {
   GstBaseTransform basetransform;
   gchar *label_file;
-  gchar **labels;
+  GArray *labels;
   gfloat score_threshold;
-  gfloat confidence_threshold;
-  gfloat iou_threshold;
-  gpointer odutils;
   GstVideoInfo video_info;
 };
 
diff --git a/subprojects/gst-plugins-bad/ext/onnx/gstonnxclient.cpp b/subprojects/gst-plugins-bad/ext/onnx/gstonnxclient.cpp
index 37060dd543..ba5ae83ca5 100644
--- a/subprojects/gst-plugins-bad/ext/onnx/gstonnxclient.cpp
+++ b/subprojects/gst-plugins-bad/ext/onnx/gstonnxclient.cpp
@@ -96,7 +96,7 @@ GstOnnxClient::GstOnnxClient (GstElement *debug_parent):debug_parent(debug_paren
     return inputImageFormat;
   }
 
-  void GstOnnxClient::setInputImageDatatype(GstTensorType datatype)
+  void GstOnnxClient::setInputImageDatatype(GstTensorDataType datatype)
   {
     inputDatatype = datatype;
     switch (inputDatatype) {
@@ -144,7 +144,7 @@ GstOnnxClient::GstOnnxClient (GstElement *debug_parent):debug_parent(debug_paren
     return inputTensorScale;
   }
 
-  GstTensorType GstOnnxClient::getInputImageDatatype(void)
+  GstTensorDataType GstOnnxClient::getInputImageDatatype(void)
   {
     return inputDatatype;
   }
diff --git a/subprojects/gst-plugins-bad/ext/onnx/gstonnxclient.h b/subprojects/gst-plugins-bad/ext/onnx/gstonnxclient.h
index 0e4f50d68e..bdec9f1a3b 100644
--- a/subprojects/gst-plugins-bad/ext/onnx/gstonnxclient.h
+++ b/subprojects/gst-plugins-bad/ext/onnx/gstonnxclient.h
@@ -56,7 +56,7 @@ namespace GstOnnxNamespace {
     bool hasSession(void);
     void setInputImageFormat(GstMlInputImageFormat format);
     GstMlInputImageFormat getInputImageFormat(void);
-    GstTensorType getInputImageDatatype(void);
+    GstTensorDataType getInputImageDatatype(void);
     void setInputImageOffset (float offset);
     float getInputImageOffset ();
     void setInputImageScale (float offset);
@@ -73,7 +73,7 @@ namespace GstOnnxNamespace {
   private:
 
     GstElement *debug_parent;
-    void setInputImageDatatype (GstTensorType datatype);
+    void setInputImageDatatype (GstTensorDataType datatype);
     template < typename T>
     void convert_image_remove_alpha (T *dest, GstMlInputImageFormat hwc,
         uint8_t **srcPtr, uint32_t srcSamplesPerPixel, uint32_t stride, T offset, T div);
@@ -91,7 +91,7 @@ namespace GstOnnxNamespace {
     std::vector < Ort::AllocatedStringPtr > outputNames;
     std::vector < GQuark > outputIds;
     GstMlInputImageFormat inputImageFormat;
-    GstTensorType inputDatatype;
+    GstTensorDataType inputDatatype;
     size_t inputDatatypeSize;
     bool fixedInputImageSize;
     float inputTensorOffset;
diff --git a/subprojects/gst-plugins-bad/ext/onnx/meson.build b/subprojects/gst-plugins-bad/ext/onnx/meson.build
index 11f93eaa3f..ceb0b9a85c 100644
--- a/subprojects/gst-plugins-bad/ext/onnx/meson.build
+++ b/subprojects/gst-plugins-bad/ext/onnx/meson.build
@@ -15,8 +15,7 @@ endif
 if onnxrt_dep.found()
     gstonnx = library('gstonnx',
     'gstonnx.c',
-    'decoders/gstobjectdetectorutils.cpp',
-    'decoders/gstssdobjectdetector.cpp',
+    'decoders/gstssdobjectdetector.c',
     'gstonnxinference.cpp',
     'gstonnxclient.cpp',
     'tensor/gsttensormeta.c',
diff --git a/subprojects/gst-plugins-bad/ext/onnx/tensor/gsttensormeta.h b/subprojects/gst-plugins-bad/ext/onnx/tensor/gsttensormeta.h
index 49983308f4..d7911312d2 100644
--- a/subprojects/gst-plugins-bad/ext/onnx/tensor/gsttensormeta.h
+++ b/subprojects/gst-plugins-bad/ext/onnx/tensor/gsttensormeta.h
@@ -25,7 +25,7 @@
 #include <gst/gst.h>
 
 /**
- * GstTensorType:
+ * GstTensorDataType:
  *
  * @GST_TENSOR_TYPE_INT4 signed 4 bit integer tensor data
  * @GST_TENSOR_TYPE_INT8 signed 8 bit integer tensor data
@@ -42,9 +42,11 @@
  * @GST_TENSOR_TYPE_FLOAT64 64 bit floating point tensor data
  * @GST_TENSOR_TYPE_BFLOAT16 "brain" 16 bit floating point tensor data
  *
+ * Describe the type of data contain in the tensor.
+ *
  * Since: 1.24
  */
-typedef enum _GstTensorType
+typedef enum _GstTensorDataType
 {
   GST_TENSOR_TYPE_INT4,
   GST_TENSOR_TYPE_INT8,
@@ -60,17 +62,17 @@ typedef enum _GstTensorType
   GST_TENSOR_TYPE_FLOAT32,
   GST_TENSOR_TYPE_FLOAT64,
   GST_TENSOR_TYPE_BFLOAT16,
-} GstTensorType;
+} GstTensorDataType;
 
 
 /**
  * GstTensor:
  *
- * @id unique tensor identifier
- * @num_dims number of tensor dimensions
- * @dims tensor dimensions
- * @type @ref GstTensorType of tensor data
- * @data @ref GstBuffer holding tensor data
+ * @id: semantically identify the contents of the tensor
+ * @num_dims: number of tensor dimensions
+ * @dims: tensor dimensions
+ * @type: #GstTensorDataType of tensor data
+ * @data: #GstBuffer holding tensor data
  *
  * Since: 1.24
  */
@@ -79,7 +81,7 @@ typedef struct _GstTensor
   GQuark id;
   gint num_dims;
   int64_t *dims;
-  GstTensorType type;
+  GstTensorDataType data_type;
   GstBuffer *data;
 } GstTensor;