Match NvDsFrameMeta with their original gstreamer Buffer

Background
I am working with Python APIs, Deepstream 6.0.1, Tesla T4, and Deepstream official develop container.

I use appsrc to feed numpy arrays to my pipeline:

img = cv2.imread("/opt/nvidia/deepstream/deepstream-6.0/samples/streams/sample_720p.jpg")
img = cv2.resize(img, (1080, 1920))
img = cv2.cvtColor(img, cv2.COLOR_BGR2RGBA)
buffer = Gst.Buffer.new_wrapped(img.tobytes())
self.source_bin_appsrc.emit("push-buffer", buffer)

The pipeline works fine, and I am able to retrieve the numpy image as well as the metadata from an object of type NvDsBatchMeta.

I am using this pipeline to create REST API that feeds numpy arrays to Deepstream.
Problem
Consider that situation where I have 2 API calls. The API call A generates a numpy_array_A and sends it to the appsrc element in the pipeline. The API call B generates a numpy_array_B and sends it to the appsrc element in the pipeline.
My pipeline process correctly the numpy arrays.
The problem is that when I retrieve the metadata, I haven’t found a way to know to which one of the two arrays (numpy_array_A or numpy_array_B) the metadata refers to.
In other works, is there a way to associated an instance of type NvDsFrameMeta to my original gstreamer buffer (created in the sample code above)? I am looking for something like an identifier that remains equal when deepstream converts the gstreamer buffer to a NvDsFrameMeta in NvDsBatchMeta. This is needed to return the correct metadata to each user of my REST API. If I had 20 concurrent calls, I need to know what metadata corresponds to every specific request.
Thank you

You can try to use the source_id para fron the NvDsFrameMeta structure.

Hi @yuweiw , thank you for your reply.
I think that source_id would allow me to identify the appsrc. However, if I have multiple frames coming through the same appsrc I don’t think I will be able to identify them, right?

You can consider using NvDsUserMeta to add your own tag for each gstbuffer through the probe function.