pyds_analytics_meta

Python bindings for NvDsAnalyticsObjInfo and NvDsAnalyticsFrameMeta in DeepStream Python API

This repository was developed followed this original repo pyds_tracker_meta and NVidia developers forum topic developer_zone

pybind11 wrapper to access Nvidia DeepStream NvDsAnalytics* meta info (NvDsAnalyticsFrameMeta NvDsAnalyticsObjInfo classes) from Python.

Introduction

This library provides utility functions to access to the NvDsAnalyticsFrameMeta and NvDsAnalyticsObjInfo types user metadata of DeepStream. See DeepStream Python API NvDsAnalytics reference for detailed explanation of functions.

Installation

Prerequisites

Install pybind11. The recommended way is to build it from source. Alternatively you might try simply pip3 install pybind11.
You should have gstreamer-1.0 and gstreamer-video-1.0 packages installed in your system. If you are using DeepStream, you most likely installed these packages.
You will need also the standard c++ compiler you usually find in Linux distributions. c++11 standard is used.

Compile the source

The source should be compiled on your target platform (Jetson or x86).
Set your DeepStream version and path in build.sh.
Launch build.sh
Install the compiled module with python setup.py install (use sudo or python3 if needed).

Usage

pyds_analytics_meta is meant to be used together with the standard Python bindings for DeepStream. Make sure you have pyds available.

Most likely you will use this library from the buffer probe callbacks of a gstreamer plugin pad, when the object tracking results are available. The deepstream-test2 python app shows you how to set up such a callback.

The example snippet provided bellow shows how to cast a user meta to a past frame object batch, and how to access all fields of the metadata. Add the following lines to the osd_sink_pad_buffer_probe method found int deepstream-test2.py, just after the batch_meta was acquired:

import pyds_analytics_meta

def osd_sink_pad_buffer_probe(pad, info, u_data):
    
    batch_meta = pyds.gst_buffer_get_nvds_batch_meta(hash(gst_buffer))
   
    print("----NvDsAnalytics Frame Meta----") 
    
    l_frame = batch_meta.frame_meta_list 
    # Iterate over list of FrameMeta
    while l_frame is not None:
        try:
            # Casting l_frame.data to ipyds.NvDsFrameMeta
            frame_meta = pyds.NvDsFrameMeta.cast(l_frame.data)
            l_user = frame_meta.frame_user_meta_list
            while l_user is not None:
                try:
                    # Cast to NvDsUserMeta and check it either NvDsAnalyticsFrameMeta or not
                    user_meta = pyds.NvDsUserMeta.cast(l_user.data)
                    if user_meta.base_meta.meta_type != pyds.nvds_get_user_meta_type(
                            "NVIDIA.DSANALYTICSFRAME.USER_META"):
                        continue

                    user_meta_analytics = pyds_analytics_meta.NvDsAnalyticsFrameMeta.cast(user_meta.user_meta_data)
                    print('objCnt:', user_meta_analytics.objCnt)
                    print('objInROIcnt:', user_meta_analytics.objInROIcnt)
                    print('objLCCumCnt:', user_meta_analytics.objLCCumCnt)
                    print('objLCCurrCnt:', user_meta_analytics.objLCCurrCnt)
                    print('ocStatus:', user_meta_analytics.ocStatus)
                    print('unique_id:', user_meta_analytics.unique_id)
                    print(user_meta_analytics.objLCCumCnt)
                except Exception as ex:
                    print('Exception', ex)
                try:
                    l_user = l_user.next
                except StopIteration:
                    break
        except StopIteration:
            break

        print("----NvDsAnalytics Object Info----")
    
        l_obj = frame_meta.obj_meta_list
        while l_obj is not None:
            try:
                # Casting l_obj.data to pyds.NvDsObjectMeta
                obj_meta = pyds.NvDsObjectMeta.cast(l_obj.data)
                user_meta_list = obj_meta.obj_user_meta_list
                while user_meta_list is not None:
                    try:
                        user_meta = pyds.NvDsUserMeta.cast(user_meta_list.data)
                        user_meta_data = user_meta.user_meta_data
                        if user_meta.base_meta.meta_type != pyds.nvds_get_user_meta_type(
                                "NVIDIA.DSANALYTICSOBJ.USER_META"):
                            continue
                        user_meta_analytics = pyds_analytics_meta.NvDsAnalyticsObjInfo.cast(user_meta.user_meta_data)
                        print('unique_id:', user_meta_analytics.unique_id)
                        print('lcStatus:', user_meta_analytics.lcStatus)
                        print('dirStatus:', user_meta_analytics.dirStatus)
                        print('ocStatus:', user_meta_analytics.ocStatus)
                        print('roiStatus:', user_meta_analytics.roiStatus)
                    except StopIteration:
                        break
                    try:
                        user_meta_list = user_meta_list.next
                    except StopIteration:
                        break
            except StopIteration:
                break
            try:
                l_obj = l_obj.next
            except StopIteration:
                break
        
        # Get next FrameMeta in list 
        try:
            l_frame=l_frame.next
        except StopIteration:
            break

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