Defining schema for message payload using nvmsgconv with newmsgapi

Accelerated Computing Intelligent Video Analytics DeepStream SDK
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Please provide complete information as applicable to your setup.

• Hardware Platform (Jetson / GPU) GPU, RTX 3090
• DeepStream Version 6.2 (omw to switching to 6.3)
• NVIDIA GPU Driver Version (valid for GPU only) 520.61.05
• Issue Type( questions, new requirements, bugs) Question

My DS app is based on testapp3, with inspiration from testapp4 regarding how to generate message payloads. I am currently using the nvmsgconv and nvmsgbroker libraries to send data to kafka from my deepstream pipeline, using the following config:

msgconv:
payload-type: 0
msg2p-newapi: 0
debug-payload-dir: /opt/nvidia/deepstream/deepstream/sources/apps/sample_apps/debug_dir

I have adjusted the nvmsgconv-library and added custom handling for my message payloads. It works but as I add more models to my pipeline, I would like to explore whether it is possible to add meta data from deepstream buffers more automatically somehow. As far as I’ve understood, this could be possible by using payload-type 2 NVDS_PAYLOAD_DEEPSTREAM_PROTOBUF.

However, setting payload-type to 2 gives me weird message payloads (put in the degug-directory), fe:

4.00�������H" CAMERA_ID

I suspect that this is because the message conversion library is expecting different data than what it is given by my application.

So my question is: where and how do I define what to include in the message payloads for the PROTOBUF payload type? Ideally, I would like for it to be for example all of the data in the “classifier meta list” for each object. I can see that the message conversion library is using the “schema.proto”-file and filling up different objects in that, but I don’t understand how it works and in what way it can be “mapped” to the metadata I want to include in the messages.

A follow-up question is: is there any reference application where the PROTOBUF message payload type is used, which I can look to for inspiration?

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nvmsgconv plugin and low level lib is opensource. you can find NVDS_PAYLOAD_DEEPSTREAM_PROTOBUF in DeepStrem SDK. then you can how to use payload-type 2 in nvds_msg2p_generate_multiple.

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Yeah I have already altered the nvmsgconv library, but I don’t understand how to use the specific payload type 2. My questsions are still:

How do I define what to include in the message payload for the PROTOBUF payload type (payload type 2)?

Is there any reference application/example where the payload type 2 is used? Maybe I can look at that in order to undetstand, but I havnt been able to find any example

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There is no update from you for a period, assuming this is not an issue any more. Hence we are closing this topic. If need further support, please open a new one. Thanks.

yes, you can see the definition in opt\nvidia\deepstream\deepstream-6.3\sources\includes\nvdsmeta_schema.h.

please refer to the code nvds_msg2p_generate_multiple in \opt\nvidia\deepstream\deepstream\sources\libs\nvmsgconv\nvmsgconv.cpp.

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