How to add metadata to plugin before Gst-nvstreammux

Accelerated Computing Intelligent Video Analytics DeepStream SDK
1

Please provide complete information as applicable to your setup.

• DeepStream Version: 7.X

I have a pipeline which in general looks like this:

source -> decode --(I want to put some data here using probe)-> process -> streammux -> nvinfer -(I want to read these data here)-> display

In 2022 it was not supported ( Adding custom meta before New Gst-nvstreammux ) but now it seems to be.

I found a mention in docs describing Adding metadata to the plugin before Gst-nvstreammux, but there is no meaningfull example showing how to properly do it.

example

I tried to add it in the the gst probe attached with GstPad.add_probe( Gst.PadProbeType.BUFFER, self.gst_video_probe)

    def gst_video_probe(
        self,
        pad: Gst.Pad,
        info: Gst.PadProbeInfo,
        *user_data: Any,
    ):
        """Video stream probe used for manipulating stream buffers."""
        gst_buffer = info.get_buffer()
        if not gst_buffer:
            logging.error("Unable to get GstBuffer.")
            return Gst.PadProbeReturn.OK
        try:
           # somehow initialize all of the arguments
            usermeta = pyds.NvDsUserMeta()

            nvinstance: pyds.NvDsMeta = pyds.gst_buffer_add_nvds_meta(
                gst_buffer,
                usermeta,
                None,
                pyds.nvds_batch_meta_copy_func,
                pyds.nvds_batch_meta_release_func,
            )

and I got

gst_buffer_add_nvds_meta(): incompatible function arguments. 
The following argument types are supported:
    1. (buffer: _GstBuffer, meta_data: capsule, user_data: capsule, copy_func: void* (void*, void*), release_func: void (void*, void*)) -> _NvDsMeta

Invoked with: 
<Gst.Buffer object at 0x71f5337d2500 (GstBuffer at 0x71f43c326650)>, 
None, 
None, 
<built-in method nvds_batch_meta_copy_func of PyCapsule object at 0x71f558d50870>, 
<built-in method nvds_batch_meta_release_func of PyCapsule object at 0x71f558d508a0>
> /workspace/eyeq/infer/eyeq/pipeline_probe.py(196)gst_video_probe()
-> nvinstance: pyds.NvDsMeta = pyds.gst_buffer_add_nvds_meta(