How to get both box in back to back detector

Please provide complete information as applicable to your setup.

• Hardware Platform (Jetson / GPU) : GPU RTX 4060
• DeepStream Version 6.4
• JetPack Version (valid for Jetson only): None
• TensorRT Version: 8.6.1.6
• NVIDIA GPU Driver Version (valid for GPU only): 12.2
• Issue Type( questions, new requirements, bugs) question
• How to reproduce the issue ? (This is for bugs. Including which sample app is using, the configuration files content, the command line used and other details for reproducing): This is not a bug
• Requirement details( This is for new requirement. Including the module name-for which plugin or for which sample application, the function description): This is not a requirement

Hi, I code a back to back detector similar to this sample with my own model in python:

As I understand, face detector works on output of person detector.
I already visualize and confirm that program can detect both people and face. I can check object is face or person by: unique_component_id.
I check parent of object by: obj_meta.parent show None
But how can I get which face belong to which person?

Can you share your python implementation?

Basically, i modify this repo: face detection repo by adding yolox detector as PGIE, change retina face to SGIE, change config as follow:

, main.py

'''
Author: zhouyuchong
Date: 2023-07-12 09:47:15
Description: 
LastEditors: zhouyuchong
LastEditTime: 2023-07-12 15:00:36
'''

import numpy as np
import math
import sys

from common.is_aarch_64 import is_aarch64
from common.bus_call import bus_call
from common.FPS import GETFPS
from common.utils import cal_ratio

from config import *
from probe import osd_sink_pad_buffer_probe, tiler_pad_buffer_probe

import gi
gi.require_version('Gst', '1.0')
from gi.repository import GLib, Gst

import ctypes
ctypes.cdll.LoadLibrary('nvdsinfer_custom_impl_retina_face/libdecodeplugin.so')


def main(args):
    if len(args) < 2:
        sys.stderr.write("usage: %s <uri1> [uri2] ... [uriN]\n" % args[0])
        sys.exit(1)

    number_sources=len(args)-1

    # Standard GStreamer initialization
    Gst.init(None)

    # Create gstreamer elements */
    # Create Pipeline element that will form a connection of other elements
    print("Creating Pipeline \n ")
    pipeline = Gst.Pipeline()
    is_live = False

    if not pipeline:
        sys.stderr.write(" Unable to create Pipeline \n")
    print("Creating streamux \n ")

    # Create nvstreammux instance to form batches from one or more sources.
    streammux = Gst.ElementFactory.make("nvstreammux", "Stream-muxer")
    if not streammux:
        sys.stderr.write(" Unable to create NvStreamMux \n")

    pipeline.add(streammux)
    for i in range(number_sources):
        print("Creating source_bin ",i," \n ")
        uri_name=args[i+1]
        if uri_name.find("rtsp://") == 0 :
            is_live = True
        source_bin=create_source_bin(i, uri_name)
        if not source_bin:
            sys.stderr.write("Unable to create source bin \n")
        pipeline.add(source_bin)
        padname="sink_%u" %i
        sinkpad= streammux.request_pad_simple(padname) 
        if not sinkpad:
            sys.stderr.write("Unable to create sink pad bin \n")
        srcpad=source_bin.get_static_pad("src")
        if not srcpad:
            sys.stderr.write("Unable to create src pad bin \n")
        srcpad.link(sinkpad)
    queue1=Gst.ElementFactory.make("queue","queue1")
    queue2=Gst.ElementFactory.make("queue","queue2")
    queue3=Gst.ElementFactory.make("queue","queue3")
    queue4=Gst.ElementFactory.make("queue","queue4")
    queue5=Gst.ElementFactory.make("queue","queue5")
    queue6=Gst.ElementFactory.make("queue","queue6")
    queue7=Gst.ElementFactory.make("queue","queue7")
    queue8=Gst.ElementFactory.make("queue","queue8")
    pipeline.add(queue1)
    pipeline.add(queue2)
    pipeline.add(queue3)
    pipeline.add(queue4)
    pipeline.add(queue5)
    pipeline.add(queue6)
    pipeline.add(queue7)
    pipeline.add(queue8)

    print("Creating Pgie \n ")
    pgie = Gst.ElementFactory.make("nvinfer", "primary-inference")
    if not pgie:
        sys.stderr.write(" Unable to create pgie \n")
    
    sgie = Gst.ElementFactory.make("nvinfer", "secondary-inference")
    if not pgie:
        sys.stderr.write(" Unable to create sgie \n")

    print("Creating tiler \n ")
    tiler=Gst.ElementFactory.make("nvmultistreamtiler", "nvtiler")
    if not tiler:
        sys.stderr.write(" Unable to create tiler \n")
    print("Creating nvvidconv \n ")
    nvvidconv = Gst.ElementFactory.make("nvvideoconvert", "convertor")
    if not nvvidconv:
        sys.stderr.write(" Unable to create nvvidconv \n")
    print("Creating nvosd \n ")
    nvosd = Gst.ElementFactory.make("nvdsosd", "onscreendisplay")
    if not nvosd:
        sys.stderr.write(" Unable to create nvosd \n")
    nvosd.set_property('process-mode',OSD_PROCESS_MODE)
    nvosd.set_property('display-text',OSD_DISPLAY_TEXT)
    if(is_aarch64()):
        print("Creating transform \n ")
        transform=Gst.ElementFactory.make("nvegltransform", "nvegl-transform")
        if not transform:
            sys.stderr.write(" Unable to create transform \n")

    print("Creating EGLSink \n")
    sink = Gst.ElementFactory.make("nveglglessink", "nvvideo-renderer")
    if not sink:
        sys.stderr.write(" Unable to create egl sink \n")

    if is_live:
        print("Atleast one of the sources is live")
        streammux.set_property('live-source', 1)

    streammux.set_property('width', 1920)
    streammux.set_property('height', 1080)
    streammux.set_property('batch-size', number_sources)
    streammux.set_property('batched-push-timeout', 4000000)

    pgie.set_property('config-file-path', "configs/config_yolox.txt")
    pgie_batch_size=pgie.get_property("batch-size")
    if(pgie_batch_size != number_sources):
        print("WARNING: Overriding infer-config batch-size",pgie_batch_size," with number of sources ", number_sources," \n")
        pgie.set_property("batch-size",number_sources)

    sgie.set_property('config-file-path', "configs/config_retinanet.txt")
    
    tiler_rows=int(math.sqrt(number_sources))
    tiler_columns=int(math.ceil((1.0*number_sources)/tiler_rows))
    tiler.set_property("rows",tiler_rows)
    tiler.set_property("columns",tiler_columns)
    tiler.set_property("width", TILED_OUTPUT_WIDTH)
    tiler.set_property("height", TILED_OUTPUT_HEIGHT)
    sink.set_property("qos",0)
    sink.set_property("sync",0)

    print("Adding elements to Pipeline \n")
    pipeline.add(pgie)
    pipeline.add(sgie)
    pipeline.add(tiler)
    pipeline.add(nvvidconv)
    pipeline.add(nvosd)
    if is_aarch64():
        pipeline.add(transform)
    pipeline.add(sink)

    print("Linking elements in the Pipeline \n")
    streammux.link(queue1)
    queue1.link(pgie)
    pgie.link(queue2)
    # queue2.link(queue8)
    queue2.link(sgie)
    sgie.link(queue8)
    queue8.link(tiler)
    # queue2.link(tiler)
    tiler.link(queue5)
    queue5.link(nvvidconv)
    nvvidconv.link(queue6)
    queue6.link(nvosd)
    if is_aarch64():
        nvosd.link(queue7)
        queue7.link(transform)
        transform.link(sink)
    else:
        nvosd.link(queue7)
        queue7.link(sink)   

    # create an event loop and feed gstreamer bus mesages to it
    loop = GLib.MainLoop()
    bus = pipeline.get_bus()
    bus.add_signal_watch()
    bus.connect ("message", bus_call, loop)

    # ratio for draw lmks
    scale_ratio = cal_ratio(NETWORK_HEIGHT, NETWORK_WIDTH, TILED_OUTPUT_HEIGHT, TILED_OUTPUT_WIDTH)
    user_data = [scale_ratio, DRAW_LMKS_SIGNAL]

    tiler_src_pad=queue8.get_static_pad("sink")
    if not tiler_src_pad:
        print(" Unable to get src pad \n")
        sys.stderr.write(" Unable to get src pad \n")
    else:
        tiler_src_pad.add_probe(Gst.PadProbeType.BUFFER, tiler_pad_buffer_probe, user_data)

    # List the sources
    print("Now playing...")
    for i, source in enumerate(args):
        if (i != 0):
            print(i, ": ", source)

    print("Starting pipeline \n")
    # start play back and listed to events		
    pipeline.set_state(Gst.State.PLAYING)
    try:
        loop.run()
    except:
        pass
    # cleanup
    print("Exiting app\n")
    pipeline.set_state(Gst.State.NULL)

def cb_newpad(decodebin, decoder_src_pad,data):
    print("In cb_newpad\n")
    caps=decoder_src_pad.get_current_caps()
    gststruct=caps.get_structure(0)
    gstname=gststruct.get_name()
    source_bin=data
    features=caps.get_features(0)

    # Need to check if the pad created by the decodebin is for video and not
    # audio.
    print("gstname=",gstname)
    if(gstname.find("video")!=-1):
        # Link the decodebin pad only if decodebin has picked nvidia
        # decoder plugin nvdec_*. We do this by checking if the pad caps contain
        # NVMM memory features.
        print("features=",features)
        if features.contains("memory:NVMM"):
            # Get the source bin ghost pad
            bin_ghost_pad=source_bin.get_static_pad("src")
            if not bin_ghost_pad.set_target(decoder_src_pad):
                sys.stderr.write("Failed to link decoder src pad to source bin ghost pad\n")
        else:
            sys.stderr.write(" Error: Decodebin did not pick nvidia decoder plugin.\n")

def decodebin_child_added(child_proxy,Object,name,user_data):
    print("Decodebin child added:", name, "\n")
    if(name.find("decodebin") != -1):
        Object.connect("child-added",decodebin_child_added,user_data)

    if "source" in name:
        obj_name = str(Object)
        if 'GstRTSPSrc' in obj_name:
            Object.set_property("drop-on-latency", True)
        

def create_source_bin(index,uri):
    print("Creating source bin")

    # Create a source GstBin to abstract this bin's content from the rest of the
    # pipeline
    bin_name="source-bin-%02d" %index
    print(bin_name)
    nbin=Gst.Bin.new(bin_name)
    if not nbin:
        sys.stderr.write(" Unable to create source bin \n")

    # Source element for reading from the uri.
    # We will use decodebin and let it figure out the container format of the
    # stream and the codec and plug the appropriate demux and decode plugins.
    uri_decode_bin=Gst.ElementFactory.make("uridecodebin", "uri-decode-bin")
    if not uri_decode_bin:
        sys.stderr.write(" Unable to create uri decode bin \n")
    # We set the input uri to the source element
    uri_decode_bin.set_property("uri",uri)
    # Connect to the "pad-added" signal of the decodebin which generates a
    # callback once a new pad for raw data has beed created by the decodebin
    uri_decode_bin.connect("pad-added",cb_newpad,nbin)
    uri_decode_bin.connect("child-added",decodebin_child_added,nbin)

    # We need to create a ghost pad for the source bin which will act as a proxy
    # for the video decoder src pad. The ghost pad will not have a target right
    # now. Once the decode bin creates the video decoder and generates the
    # cb_newpad callback, we will set the ghost pad target to the video decoder
    # src pad.
    Gst.Bin.add(nbin,uri_decode_bin)
    bin_pad=nbin.add_pad(Gst.GhostPad.new_no_target("src",Gst.PadDirection.SRC))
    if not bin_pad:
        sys.stderr.write(" Failed to add ghost pad in source bin \n")
        return None
    return nbin

if __name__ == '__main__':
    sys.exit(main(sys.argv))

probe function file

'''
Author: zhouyuchong
Date: 2023-07-12 10:26:33
Description: 
LastEditors: zhouyuchong
LastEditTime: 2023-07-12 14:18:03
'''
import gi
gi.require_version('Gst', '1.0')
from gi.repository import GObject, Gst
import numpy as np

from rface_custom import parse_objects_from_tensor_meta

import pyds

def tiler_pad_buffer_probe(pad,info,u_data):
    gst_buffer = info.get_buffer()
    if not gst_buffer:
        print("Unable to get GstBuffer ")
        return
    # Retrieve batch metadata from the gst_buffer
    # Note that pyds.gst_buffer_get_nvds_batch_meta() expects the
    # C address of gst_buffer as input, which is obtained with hash(gst_buffer)
    batch_meta = pyds.gst_buffer_get_nvds_batch_meta(hash(gst_buffer))

    l_frame = batch_meta.frame_meta_list
    while l_frame is not None:
        try:
            # Note that l_frame.data needs a cast to pyds.NvDsFrameMeta
            # The casting is done by pyds.NvDsFrameMeta.cast()
            # The casting also keeps ownership of the underlying memory
            # in the C code, so the Python garbage collector will leave
            # it alone.
            frame_meta = pyds.NvDsFrameMeta.cast(l_frame.data)
        except StopIteration:
            break

        frame_number = frame_meta.frame_num
        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)
            except StopIteration:
                break
            print("obj_meta.unique_component_id", obj_meta.unique_component_id)
            print("l_obj.parent: ", obj_meta.class_id, obj_meta.parent)

            try:
                l_obj = l_obj.next
            except StopIteration:
                break
        try:
            l_frame = l_frame.next
        except StopIteration:
            break
    return Gst.PadProbeReturn.OK
    

def osd_sink_pad_buffer_probe(pad, info, u_data):
    if not u_data[1]:
        return Gst.PadProbeReturn.OK	
    scale_ratio = u_data[0]
    frame_number=0
    gst_buffer = info.get_buffer()
    if not gst_buffer:
        print("Unable to get GstBuffer ")
        return

    batch_meta = pyds.gst_buffer_get_nvds_batch_meta(hash(gst_buffer))    
    l_frame = batch_meta.frame_meta_list
    while l_frame is not None:
        try:
            frame_meta = pyds.NvDsFrameMeta.cast(l_frame.data)
        except StopIteration:
            break
        
        frame_number=frame_meta.frame_num
        result_landmark = []
        l_user=frame_meta.frame_user_meta_list
        while l_user is not None:
            try:
                user_meta=pyds.NvDsUserMeta.cast(l_user.data) 
            except StopIteration:
                break
            
            if(user_meta and user_meta.base_meta.meta_type==pyds.NvDsMetaType.NVDSINFER_TENSOR_OUTPUT_META): 
                try:
                    tensor_meta = pyds.NvDsInferTensorMeta.cast(user_meta.user_meta_data)
                except StopIteration:
                    break
                
                layer = pyds.get_nvds_LayerInfo(tensor_meta, 0)
                result_landmark = parse_objects_from_tensor_meta(layer)
                   
            try:
                l_user=l_user.next
            except StopIteration:
                break    
          
        num_rects = frame_meta.num_obj_meta
        face_count = 0
        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)
                
            except StopIteration:
                break

            print("obj_meta.unique_component_id: ", obj_meta.unique_component_id)
            # set bbox color in rgba
            obj_meta.rect_params.border_color.set(1.0, 1.0, 1.0, 0.0)
            # set the border width in pixel
            obj_meta.rect_params.border_width=5
            obj_meta.rect_params.has_bg_color=1
            obj_meta.rect_params.bg_color.set(0.0, 0.5, 0.3, 0.4)
            face_count +=1
            #print(face_count)
            try: 
                l_obj=l_obj.next

            except StopIteration:
                break

        # draw 5 landmarks for each rect
        # display_meta.num_circles = len(result_landmark) * 5
        display_meta=pyds.nvds_acquire_display_meta_from_pool(batch_meta)
        ccount = 0
        for i in range(len(result_landmark)):
            # scale coordinates
            landmarks = result_landmark[i] * scale_ratio
            # nvosd struct can only draw MAX 16 elements once 
            # so acquire a new display meta for every face detected
            display_meta=pyds.nvds_acquire_display_meta_from_pool(batch_meta)   
            display_meta.num_circles = 5
            ccount = 0
            for j in range(5):
                py_nvosd_circle_params = display_meta.circle_params[ccount]
                py_nvosd_circle_params.circle_color.set(0.0, 0.0, 1.0, 1.0)
                py_nvosd_circle_params.has_bg_color = 1
                py_nvosd_circle_params.bg_color.set(0.0, 0.0, 0.0, 1.0)
                py_nvosd_circle_params.xc = int(landmarks[j * 2]) if int(landmarks[j * 2]) > 0 else 0
                py_nvosd_circle_params.yc = int(landmarks[j * 2 + 1]) if int(landmarks[j * 2 + 1]) > 0 else 0
                py_nvosd_circle_params.radius=2
                ccount = ccount + 1
            pyds.nvds_add_display_meta_to_frame(frame_meta, display_meta)

        display_meta=pyds.nvds_acquire_display_meta_from_pool(batch_meta)       
        display_meta.num_labels = 1
        py_nvosd_text_params = display_meta.text_params[0]
        # Setting display text to be shown on screen
        # Note that the pyds module allocates a buffer for the string, and the
        # memory will not be claimed by the garbage collector.
        # Reading the display_text field here will return the C address of the
        # allocated string. Use pyds.get_string() to get the string content.
        py_nvosd_text_params.display_text = "Frame Number={} Number of Objects={}".format(frame_number, num_rects)

        # Now set the offsets where the string should appear
        py_nvosd_text_params.x_offset = 10
        py_nvosd_text_params.y_offset = 12

        # Font , font-color and font-size
        py_nvosd_text_params.font_params.font_name = "Serif"
        py_nvosd_text_params.font_params.font_size = 10
        # set(red, green, blue, alpha); set to White
        py_nvosd_text_params.font_params.font_color.set(1.0, 1.0, 1.0, 1.0)

        # Text background color
        py_nvosd_text_params.set_bg_clr = 1
        # set(red, green, blue, alpha); set to Black
        py_nvosd_text_params.text_bg_clr.set(0.0, 0.0, 0.0, 1.0)
        # Using pyds.get_string() to get display_text as string
        # print(pyds.get_string(py_nvosd_text_params.display_text))
        pyds.nvds_add_display_meta_to_frame(frame_meta, display_meta)
        try:
            l_frame=l_frame.next
        except StopIteration:
            break
			
    return Gst.PadProbeReturn.OK	

config_yolox.txt

[property]
gpu-id=0
net-scale-factor=1.0

# 0:RGB 1:BGR
model-color-format=0

model-engine-file=../models/yolox/yolox_s.trt

labelfile-path=labels.txt
num-detected-classes=80

interval=0
gie-unique-id=1
process-mode=1
batch-size=16
# 0=Detector, 1=Classifier, 2=Segmentation, 100=Other
network-type=0

# 0:Group Rectange 1:DBSCAN 2:NMS 3:DBSCAN+NMS 4:None
cluster-mode=4
maintain-aspect-ratio=0
parse-bbox-func-name=NvDsInferParseCustomYolox
custom-lib-path=../nvdsinfer_custom_impl_yolox/libnvdsinfer_custom_impl_yolox.so

[class-attrs-all]
pre-cluster-threshold=0.25

interval=15

Config for retina_face

[property]
gpu-id=0
net-scale-factor=1.0
offsets=104.0;117.0;123.0

# 0:RGB 1:BGR
model-color-format=1

# onnx-file=../models/retina_face/FaceDetector.onnx
model-engine-file=../models/retina_face/retina_r50.engine

labelfile-path=../models/retina_face/labels.txt

interval=0
gie-unique-id=2
process-mode=1
batch-size=16

# 0=Detector, 1=Classifier, 2=Segmentation, 100=Other
network-type=0
output-blob-names=prob
num-detected-classes=1
output-tensor-meta=1
maintain-aspect-ratio=1
operate-on-gie-id=1
operate-on-class-ids=0

# 0:Group Rectange 1:DBSCAN 2:NMS 3:DBSCAN+NMS 4:None
cluster-mode=4
maintain-aspect-ratio=0
parse-bbox-func-name=NvDsInferParseCustomRetinaface
custom-lib-path=../nvdsinfer_custom_impl_retina_face/libnvdsinfer_custom_impl_retinaface.so

[class-attrs-all]
pre-cluster-threshold=0.6
nms-iou-threshold=0.5

The “parent” can only be get right after the SGIE element. Please get the “parent” in the probe function attached in the src pad of the sgie element.

I tried, but the result is the same:

import numpy as np
import math
import sys

from common.is_aarch_64 import is_aarch64
from common.bus_call import bus_call
from common.FPS import GETFPS
from common.utils import cal_ratio

from config import *
from probe import osd_sink_pad_buffer_probe, tiler_pad_buffer_probe

import gi
gi.require_version('Gst', '1.0')
from gi.repository import GLib, Gst


import ctypes
ctypes.cdll.LoadLibrary('nvdsinfer_custom_impl_retina_face/libdecodeplugin.so')


def make_elm_or_print_err(factoryname, name, printedname, detail=""):
    """ Creates an element with Gst Element Factory make.
        Return the element  if successfully created, otherwise print
        to stderr and return None.
    """
    print("Creating", printedname)
    elm = Gst.ElementFactory.make(factoryname, name)
    if not elm:
        sys.stderr.write("Unable to create " + printedname + " \n")
        if detail:
            sys.stderr.write(detail)
    return elm

def main(args):
    if len(args) < 2:
        sys.stderr.write("usage: %s <uri1> [uri2] ... [uriN]\n" % args[0])
        sys.exit(1)

    number_sources=len(args)-1

    # Standard GStreamer initialization
    Gst.init(None)

    # Create gstreamer elements */
    # Create Pipeline element that will form a connection of other elements
    print("Creating Pipeline \n ")
    pipeline = Gst.Pipeline()
    is_live = False

    if not pipeline:
        sys.stderr.write(" Unable to create Pipeline \n")
    print("Creating streamux \n ")

    # Create nvstreammux instance to form batches from one or more sources.
    streammux = Gst.ElementFactory.make("nvstreammux", "Stream-muxer")
    if not streammux:
        sys.stderr.write(" Unable to create NvStreamMux \n")

    pipeline.add(streammux)
    for i in range(number_sources):
        print("Creating source_bin ",i," \n ")
        uri_name=args[i+1]
        if uri_name.find("rtsp://") == 0 :
            is_live = True
        source_bin=create_source_bin(i, uri_name)
        if not source_bin:
            sys.stderr.write("Unable to create source bin \n")
        pipeline.add(source_bin)
        padname="sink_%u" %i
        sinkpad= streammux.request_pad_simple(padname) 
        if not sinkpad:
            sys.stderr.write("Unable to create sink pad bin \n")
        srcpad=source_bin.get_static_pad("src")
        if not srcpad:
            sys.stderr.write("Unable to create src pad bin \n")
        srcpad.link(sinkpad)
    queue1=Gst.ElementFactory.make("queue","queue1")
    queue2=Gst.ElementFactory.make("queue","queue2")
    queue3=Gst.ElementFactory.make("queue","queue3")
    queue4=Gst.ElementFactory.make("queue","queue4")
    queue5=Gst.ElementFactory.make("queue","queue5")
    queue6=Gst.ElementFactory.make("queue","queue6")
    queue7=Gst.ElementFactory.make("queue","queue7")
    queue8=Gst.ElementFactory.make("queue","queue8")
    pipeline.add(queue1)
    pipeline.add(queue2)
    pipeline.add(queue3)
    pipeline.add(queue4)
    pipeline.add(queue5)
    pipeline.add(queue6)
    pipeline.add(queue7)
    pipeline.add(queue8)

    print("Creating Pgie \n ")
    pgie = Gst.ElementFactory.make("nvinfer", "primary-inference")
    if not pgie:
        sys.stderr.write(" Unable to create pgie \n")
    
    sgie = Gst.ElementFactory.make("nvinfer", "secondary-inference")
    if not pgie:
        sys.stderr.write(" Unable to create sgie \n")

    print("Creating tiler \n ")
    tiler=Gst.ElementFactory.make("nvmultistreamtiler", "nvtiler")
    if not tiler:
        sys.stderr.write(" Unable to create tiler \n")
    print("Creating nvvidconv \n ")
    nvvidconv = Gst.ElementFactory.make("nvvideoconvert", "convertor")
    if not nvvidconv:
        sys.stderr.write(" Unable to create nvvidconv \n")
    print("Creating nvosd \n ")
    nvosd = Gst.ElementFactory.make("nvdsosd", "onscreendisplay")
    if not nvosd:
        sys.stderr.write(" Unable to create nvosd \n")
    nvosd.set_property('process-mode',OSD_PROCESS_MODE)
    nvosd.set_property('display-text',OSD_DISPLAY_TEXT)
    if(is_aarch64()):
        print("Creating transform \n ")
        transform=Gst.ElementFactory.make("nvegltransform", "nvegl-transform")
        if not transform:
            sys.stderr.write(" Unable to create transform \n")

    print("Creating EGLSink \n")
    sink = make_elm_or_print_err("filesink", "filesink", "Sink")

    sink.set_property("location", OUTPUT_VIDEO_NAME)
    sink.set_property("sync", 0)
    sink.set_property("async", 0)

    if is_live:
        print("Atleast one of the sources is live")
        streammux.set_property('live-source', 1)

    streammux.set_property('width', 1920)
    streammux.set_property('height', 1080)
    streammux.set_property('batch-size', number_sources)
    streammux.set_property('batched-push-timeout', 4000000)

    pgie.set_property('config-file-path', "configs/config_yolox.txt")
    pgie_batch_size=pgie.get_property("batch-size")
    if(pgie_batch_size != number_sources):
        print("WARNING: Overriding infer-config batch-size",pgie_batch_size," with number of sources ", number_sources," \n")
        pgie.set_property("batch-size",number_sources)

    sgie.set_property('config-file-path', "configs/config_retinanet.txt")
    
    tiler_rows=int(math.sqrt(number_sources))
    tiler_columns=int(math.ceil((1.0*number_sources)/tiler_rows))
    tiler.set_property("rows",tiler_rows)
    tiler.set_property("columns",tiler_columns)
    tiler.set_property("width", TILED_OUTPUT_WIDTH)
    tiler.set_property("height", TILED_OUTPUT_HEIGHT)
    sink.set_property("qos",0)
    sink.set_property("sync",0)

    print("Adding elements to Pipeline \n")
    pipeline.add(pgie)
    pipeline.add(sgie)
    pipeline.add(tiler)
    pipeline.add(nvvidconv)
    pipeline.add(nvosd)
    if is_aarch64():
        pipeline.add(transform)
    pipeline.add(sink)

    print("Linking elements in the Pipeline \n")
    streammux.link(queue1)
    queue1.link(pgie)
    pgie.link(queue2)
    queue2.link(nvvidconv)
    nvvidconv.link(queue3)
    queue3.link(sgie)
    sgie.link(queue4)
    queue4.link(tiler)
    tiler.link(queue5)
    queue5.link(nvosd)
    if is_aarch64():
        nvosd.link(queue7)
        queue7.link(transform)
        transform.link(sink)
    else:
        nvosd.link(queue7)
        queue7.link(sink)   

    # create an event loop and feed gstreamer bus mesages to it
    loop = GLib.MainLoop()
    bus = pipeline.get_bus()
    bus.add_signal_watch()
    bus.connect ("message", bus_call, loop)

    # ratio for draw lmks
    scale_ratio = cal_ratio(NETWORK_HEIGHT, NETWORK_WIDTH, TILED_OUTPUT_HEIGHT, TILED_OUTPUT_WIDTH)
    user_data = [scale_ratio, DRAW_LMKS_SIGNAL]


    sgie_src_pad=sgie.get_static_pad("src")
    sgie_src_pad.add_probe(Gst.PadProbeType.BUFFER, tiler_pad_buffer_probe, user_data)


    # List the sources
    print("Now playing...")
    for i, source in enumerate(args):
        if (i != 0):
            print(i, ": ", source)

    print("Starting pipeline \n")
    # start play back and listed to events		
    pipeline.set_state(Gst.State.PLAYING)
    try:
        loop.run()
    except:
        pass
    # cleanup
    print("Exiting app\n")
    pipeline.set_state(Gst.State.NULL)

def cb_newpad(decodebin, decoder_src_pad,data):
    print("In cb_newpad\n")
    caps=decoder_src_pad.get_current_caps()
    gststruct=caps.get_structure(0)
    gstname=gststruct.get_name()
    source_bin=data
    features=caps.get_features(0)

    # Need to check if the pad created by the decodebin is for video and not
    # audio.
    print("gstname=",gstname)
    if(gstname.find("video")!=-1):
        # Link the decodebin pad only if decodebin has picked nvidia
        # decoder plugin nvdec_*. We do this by checking if the pad caps contain
        # NVMM memory features.
        print("features=",features)
        if features.contains("memory:NVMM"):
            # Get the source bin ghost pad
            bin_ghost_pad=source_bin.get_static_pad("src")
            if not bin_ghost_pad.set_target(decoder_src_pad):
                sys.stderr.write("Failed to link decoder src pad to source bin ghost pad\n")
        else:
            sys.stderr.write(" Error: Decodebin did not pick nvidia decoder plugin.\n")

def decodebin_child_added(child_proxy,Object,name,user_data):
    print("Decodebin child added:", name, "\n")
    if(name.find("decodebin") != -1):
        Object.connect("child-added",decodebin_child_added,user_data)

    if "source" in name:
        obj_name = str(Object)
        if 'GstRTSPSrc' in obj_name:
            Object.set_property("drop-on-latency", True)
        

def create_source_bin(index,uri):
    print("Creating source bin")

    # Create a source GstBin to abstract this bin's content from the rest of the
    # pipeline
    bin_name="source-bin-%02d" %index
    print(bin_name)
    nbin=Gst.Bin.new(bin_name)
    if not nbin:
        sys.stderr.write(" Unable to create source bin \n")

    # Source element for reading from the uri.
    # We will use decodebin and let it figure out the container format of the
    # stream and the codec and plug the appropriate demux and decode plugins.
    uri_decode_bin=Gst.ElementFactory.make("uridecodebin", "uri-decode-bin")
    if not uri_decode_bin:
        sys.stderr.write(" Unable to create uri decode bin \n")
    # We set the input uri to the source element
    uri_decode_bin.set_property("uri",uri)
    # Connect to the "pad-added" signal of the decodebin which generates a
    # callback once a new pad for raw data has beed created by the decodebin
    uri_decode_bin.connect("pad-added",cb_newpad,nbin)
    uri_decode_bin.connect("child-added",decodebin_child_added,nbin)

    # We need to create a ghost pad for the source bin which will act as a proxy
    # for the video decoder src pad. The ghost pad will not have a target right
    # now. Once the decode bin creates the video decoder and generates the
    # cb_newpad callback, we will set the ghost pad target to the video decoder
    # src pad.
    Gst.Bin.add(nbin,uri_decode_bin)
    bin_pad=nbin.add_pad(Gst.GhostPad.new_no_target("src",Gst.PadDirection.SRC))
    if not bin_pad:
        sys.stderr.write(" Failed to add ghost pad in source bin \n")
        return None
    return nbin

if __name__ == '__main__':
    sys.exit(main(sys.argv))

When I print obj_meta to console, it gets:

l_obj.parent:  0 None
obj_meta.unique_component_id 2
l_obj.parent:  0 None
obj_meta.unique_component_id 1
l_obj.parent:  0 None
obj_meta.unique_component_id 1
l_obj.parent:  0 None
obj_meta.unique_component_id 1
l_obj.parent:  0 None

I also check sample from: deepstream_lpr_app/deepstream-lpr-app/deepstream_lpr_app.c at master · NVIDIA-AI-IOT/deepstream_lpr_app · GitHub. It seems they could take parent of object before on screen display element

I tried with the modified deepstream-test2, it works.

deepstream-test2-new.zip (12.6 KB)

1 Like

Tks you. I would check this.

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