Add ONNX export metadata (#7353)

export.py

@@ -140,7 +140,13 @@ def export_onnx(model, im, file, opset, train, dynamic, simplify, prefix=colorst
         # Checks
         model_onnx = onnx.load(f)  # load onnx model
         onnx.checker.check_model(model_onnx)  # check onnx model
-        # LOGGER.info(onnx.helper.printable_graph(model_onnx.graph))  # print
+
+        # Metadata
+        d = {'stride': int(max(model.stride)), 'names': model.names}
+        for k, v in d.items():
+            meta = model_onnx.metadata_props.add()
+            meta.key, meta.value = k, str(v)
+        onnx.save(model_onnx, f)
 
         # Simplify
         if simplify:

models/common.py

@@ -328,6 +328,9 @@ class DetectMultiBackend(nn.Module):
             import onnxruntime
             providers = ['CUDAExecutionProvider', 'CPUExecutionProvider'] if cuda else ['CPUExecutionProvider']
             session = onnxruntime.InferenceSession(w, providers=providers)
+            meta = session.get_modelmeta().custom_metadata_map  # metadata
+            if 'stride' in meta:
+                stride, names = int(meta['stride']), eval(meta['names'])
         elif xml:  # OpenVINO
             LOGGER.info(f'Loading {w} for OpenVINO inference...')
             check_requirements(('openvino-dev',))  # requires openvino-dev: https://pypi.org/project/openvino-dev/