analytics: Add APIs to add or get a GstTensorMeta

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6000>

subprojects/gst-plugins-bad/ext/onnx/gstonnxclient.cpp

@@ -329,9 +329,7 @@ GstOnnxClient::GstOnnxClient (GstElement *debug_parent):debug_parent(debug_paren
       &outputs, GstBuffer * buffer)
   {
     size_t num_tensors = outputNamesRaw.size ();
-    GstTensorMeta *tmeta = (GstTensorMeta *) gst_buffer_add_meta (buffer,
-        gst_tensor_meta_get_info (),
-        NULL);
+    GstTensorMeta *tmeta = gst_buffer_add_tensor_meta (buffer);
     tmeta->num_tensors = num_tensors;
     tmeta->tensors = g_new (GstTensor *, num_tensors);
     bool hasIds = outputIds.size () == num_tensors;

subprojects/gst-plugins-bad/gst-libs/gst/analytics/gsttensormeta.c

@@ -76,6 +76,48 @@ gst_tensor_meta_get_info (void)
   return tmeta_info;
 }
 
+/**
+ * gst_buffer_add_tensor_meta:
+ * @buffer: A writable #GstBuffer
+ *
+ * Adds a #GstTensorMeta to a buffer or returns the existing one
+ *
+ * Returns: (transfer none): The new #GstTensorMeta
+ *
+ * Since: 1.26
+ */
+
+GstTensorMeta *
+gst_buffer_add_tensor_meta (GstBuffer * buffer)
+{
+  GstTensorMeta *tmeta;
+
+  tmeta = gst_buffer_get_tensor_meta (buffer);
+  if (tmeta)
+    return tmeta;
+
+  return (GstTensorMeta *) gst_buffer_add_meta (buffer,
+      gst_tensor_meta_get_info (), NULL);
+}
+
+/**
+ * gst_buffer_get_tensor_meta:
+ * @buffer: A #GstBuffer
+ *
+ * Gets the #GstTensorMeta from a buffer
+ *
+ * Returns: (nullable)(transfer none): The #GstTensorMeta if there is wone
+ *
+ * Since: 1.26
+ */
+
+GstTensorMeta *
+gst_buffer_get_tensor_meta (GstBuffer * buffer)
+{
+  return (GstTensorMeta *) gst_buffer_get_meta (buffer,
+      GST_TENSOR_META_API_TYPE);
+}
+
 gint
 gst_tensor_meta_get_index_from_id (GstTensorMeta * meta, GQuark id)
 {

subprojects/gst-plugins-bad/gst-libs/gst/analytics/gsttensormeta.h

@@ -33,10 +33,9 @@
 
 /**
  * GstTensorMeta:
- * @meta base GstMeta
- * @num_tensors number of tensors
- * @tensor @ref GstTensor for each tensor
- * @batch_size model batch size
+ * @meta: parent
+ * @num_tensors: number of tensors
+ * @tensor: (array length=num_tensors): a #GstTensor for each tensor
  *
  * Since: 1.26
  */
@@ -65,6 +64,14 @@ const GstMetaInfo *gst_tensor_meta_get_info (void);
 GST_ANALYTICS_META_API
 gint gst_tensor_meta_get_index_from_id(GstTensorMeta *meta, GQuark id);
 
+GST_ANALYTICS_META_API
+GstTensorMeta *
+gst_buffer_add_tensor_meta (GstBuffer * buffer);
+
+GST_ANALYTICS_META_API
+GstTensorMeta *
+gst_buffer_get_tensor_meta (GstBuffer * buffer);
+
 G_END_DECLS
 
 #endif