How to generate fake Boxes metadata in custom gstreamer plugin with pyds?

[LoveNvidia]

• Hardware Platform (Jetson / GPU) : Jetson
• DeepStream Version : 5.1
• JetPack Version (valid for Jetson only) : 4.5
• TensorRT Version : 7.1.3

Hi,
Firstly, I have a question:
When two nvinfer element are stacked. The first and second nvinfer elements are pgie and sgie respectively.
Q: When the pgie-nvinfer detect objects and generate boxes for those then the boxes metadata are created. So the sgie-nvinfer receives the boxes and crops objects from frames? or the pgie crops the objects and sgie-nvinfer use patches of cropped for doing inference?

Continue…
I want to write a custom plugin to generate fake car/vehicle bounding boxes metadata and the append to buffer for processing the next element(sgie-nvinfer).

The pgie-nvinfer is trafficcamnet model, I want to generate fake boxes of this model for next element(sgie-nvinfer)

[Fiona.Chen]

@LoveNvidia

Q: When the pgie-nvinfer detect some objects and generate boxes for those then the bboxes metadata are created and sgie-nvinfer receive the boxes and crop those from frames or the pgie crop and sgie-nvinfer use these cropped patches for inference?

Yes. PGIE detect objects and generate object meta with bbox information.SGIE get the object meta and crop the object images from video and do the inference.

@LoveNvidia

Continue…
I want to write a custom plugin to generate fake car/vehicle bounding boxes metadata and the append to buffer for processing the next element(sgie-nvinfer).

There is sample plugin gst-dsexample source code in /opt/nvidia/deepstream/deepstream/sources/gst-pluins/gst-dsexample. The code of generating object meta is in attach_metadata_full_frame() function.

Please read the document and source code carefully and make sure you are already familiar with gstreamer.
https://docs.nvidia.com/metropolis/deepstream/dev-guide/text/DS_plugin_metadata.html
https://docs.nvidia.com/metropolis/deepstream/dev-guide/text/DS_plugin_gst-nvinfer.html