I could not convert input streams to gray scale and resize them to [360,640] in Gstreamer-python to be used with Deepstream model inference in future?

**• Hardware Platform Ubuntu 20.04 with Nvidia GeForce GTX 1080 Ti
**• DeepStream 6.3-triton-multiarch Docker image
**• TensorRT 8.5.3
**• NVIDIA GPU Driver version 555.42.02
I’ve attempted to convert RGB to grayscale using techniques like the videoconvert and chromahold elements in GStreamer, but haven’t had success. Now, I’m trying to preprocess the input by resizing and converting it using OpenCV (cv2), but it’s still not working as expected. Can anyone help me rewrite the correct code for this?
Here is the base code for multi-stream using Gstreamer.

import sys

sys.path.append('../')
import gi
import configparser

gi.require_version('Gst', '1.0')
from gi.repository import GLib, Gst
from ctypes import *
import time
import sys
import math
import platform
from common.is_aarch_64 import is_aarch64
from common.bus_call import bus_call
from common.FPS import PERF_DATA
import numpy as np
import pyds
import cv2
import os
import os.path
from os import path

# Callback function for new pads
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)

    if gstname.find("video") != -1:
        if features.contains("memory:NVMM"):
            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")

# Callback function for when a child is added to the decodebin
def decodebin_child_added(child_proxy, Object, name, user_data):
    print("Decodebin child added:", name, "\n")

# Function to create a source bin
def create_source_bin(index, uri):
    print("Creating source bin")
    bin_name = "source-bin-%02d" % index
    nbin = Gst.Bin.new(bin_name)
    if not nbin:
        sys.stderr.write("Unable to create source bin \n")

    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")
    uri_decode_bin.set_property("uri", uri)
    uri_decode_bin.connect("pad-added", cb_newpad, nbin)
    uri_decode_bin.connect("child-added", decodebin_child_added, nbin)

    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

# Function to convert frame to grayscale using OpenCV
def convert_to_grayscale(frame):
    gray_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    return gray_frame

# Bus call function to handle messages
def bus_call(bus, message, loop):
    t = message.type
    if t == Gst.MessageType.EOS:
        print("End-of-stream\n")
        loop.quit()
    elif t == Gst.MessageType.ERROR:
        err, debug = message.parse_error()
        print("Error: %s: %s\n" % (err, debug))
        loop.quit()
    return True

# Main function
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

    Gst.init(None)
    pipeline = Gst.Pipeline()
    is_live = False

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

    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):
        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.get_request_pad(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)

    # Calculate the dimensions of the grid dynamically
    num_rows = int(math.sqrt(number_sources))
    num_cols = int(math.ceil(number_sources / num_rows))

    # Create tiler element
    tiler = Gst.ElementFactory.make("nvmultistreamtiler", "Tiler")
    if not tiler:
        sys.stderr.write("Unable to create nvmultistreamtiler \n")

    tiler.set_property("rows", num_rows)
    tiler.set_property("columns", num_cols)
    tiler.set_property("width", 1920)
    tiler.set_property("height", 1080)

    nvvidconv = Gst.ElementFactory.make("nvvideoconvert", "convertor")
    if not nvvidconv:
        sys.stderr.write("Unable to create nvvideoconvert \n")
    nvosd = Gst.ElementFactory.make("nvdsosd", "onscreendisplay")
    if not nvosd:
        sys.stderr.write("Unable to create nvdsosd \n")
    sink = Gst.ElementFactory.make("nveglglessink", "nvvideo-renderer")
    if not sink:
        sys.stderr.write("Unable to create egl sink \n")

    if 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)

    print("Adding elements to Pipeline \n")
    pipeline.add(tiler)
    pipeline.add(nvvidconv)
    pipeline.add(nvosd)
    pipeline.add(sink)

    print("Linking elements in the Pipeline \n")
    streammux.link(tiler)
    tiler.link(nvvidconv)
    nvvidconv.link(nvosd)
    nvosd.link(sink)

    loop = GLib.MainLoop()
    bus = pipeline.get_bus()
    bus.add_signal_watch()
    bus.connect("message", bus_call, loop)

    print("Now playing...")
    for i, source in enumerate(args[1:]):
        print(i, ": ", source)

    print("Starting pipeline \n")
    pipeline.set_state(Gst.State.PLAYING)
    try:
        loop.run()
    except KeyboardInterrupt:
        print("Keyboard interrupt detected")
    finally:
        print("Stopping pipeline \n")
        pipeline.set_state(Gst.State.NULL)
        loop.quit()

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

Is your model input gray? You need to first add model-color-format=2 to the nvinfer configuration file.

can you share your model and project ?

yeah sure, I can share what i wrote in config file and the actual deepstream python app. My model is a semantic segmentation model that accepts gray scale frames with a specific dimensions [360,640]. I have created an engine file which I am using.

Config File:

[property]
gpu-id=0
net-scale-factor=0.0039215697906911373
#tlt-model-key=none
#infer-dims=1;360;640
onnx-file=/opt/nvidia/deepstream/deepstream-6.3/sources/deepstream_python_apps/apps/deepstream-seg/seg_model.onnx
model-engine-file=/opt/nvidia/deepstream/deepstream-6.3/sources/deepstream_python_apps/apps/deepstream-seg/seg_model.engine
#labelfile-path=</path/to/your/label_file.txt>
#input-blob-names=input
output-blob-names=output
infer-dims=1;360;640
#input-blob-names=input
force-implicit-batch-dim=1
batch-size=1
process-mode=1
## 0=FP32, 1=INT8, 2=FP16 mode
network-mode=0
interval=0
gie-unique-id=1
#change the input to gray scale
model-color-format=2
network-type=2
#output-blob-names=output
#parse-bbox-func-name=NvDsInferParseCustomSegMask
#custom-lib-path=</path/to/your/customparser.so>

and the following is the the deepstream application code i took from the sample apps for segmentation for multistream. Here is that code:

import sys
from syslog import LOG_WARNING

sys.path.append('../')
import gi
import configparser

gi.require_version('Gst', '1.0')
from gi.repository import GLib, Gst
from ctypes import *
import time
import sys
import math
import platform
from common.is_aarch_64 import is_aarch64
from common.bus_call import bus_call
from common.FPS import PERF_DATA
import numpy as np
import pyds
import cv2
import os
import os.path
from os import path
import argparse

perf_data = None

MAX_DISPLAY_LEN = 64
MUXER_OUTPUT_WIDTH = 1920
MUXER_OUTPUT_HEIGHT = 1080
MUXER_BATCH_TIMEOUT_USEC = 4000000
TILED_OUTPUT_WIDTH = 1920
TILED_OUTPUT_HEIGHT = 1080
GST_CAPS_FEATURES_NVMM = "memory:NVMM"

# tiler_sink_pad_buffer_probe  will extract metadata received on tiler sink pad
# and re-size and binarize segmentation mask array to save to image
def tiler_sink_pad_buffer_probe(pad, info, u_data):
    frame_number = 0
    num_rects = 0
    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
        num_rects = frame_meta.num_obj_meta
        is_first_obj = True
        save_image = False
        obj_number = 0
        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
            if is_first_obj and frame_number % 30 == 0:
                is_first_obj = False
                rectparams = obj_meta.rect_params # Retrieve rectparams for re-sizing mask to correct dims
                maskparams = obj_meta.mask_params # Retrieve maskparams
                mask_image = resize_mask(maskparams, math.floor(rectparams.width), math.floor(rectparams.height)) # Get resized mask array
                
                img_path = "{}/stream_{}/frame_{}.jpg".format(folder_name, frame_meta.pad_index, frame_number)
                cv2.imwrite(img_path, mask_image) # Save mask to image
            
            try:
                l_obj = l_obj.next
                obj_number += 1
            except StopIteration:
                break

        print("Frame Number=", frame_number, "Number of Objects=", num_rects)
        # update frame rate through this probe
        stream_index = "stream{0}".format(frame_meta.pad_index)
        global perf_data
        perf_data.update_fps(stream_index)
        try:
            l_frame = l_frame.next
        except StopIteration:
            break

    return Gst.PadProbeReturn.OK


def clip(val, low, high):
    if val < low:
        return low 
    elif val > high:
        return high 
    else:
        return val

# Resize and binarize mask array for interpretable segmentation mask
def resize_mask(maskparams, target_width, target_height):
    src = maskparams.get_mask_array() # Retrieve mask array
    dst = np.empty((target_height, target_width), src.dtype) # Initialize array to store re-sized mask
    original_width = maskparams.width
    original_height = maskparams.height
    ratio_h = float(original_height) / float(target_height)
    ratio_w = float(original_width) / float(target_width)
    threshold = maskparams.threshold
    channel = 1

    # Resize from original width/height to target width/height 
    for y in range(target_height):
        for x in range(target_width):
            x0 = float(x) * ratio_w
            y0 = float(y) * ratio_h
            left = int(clip(math.floor(x0), 0.0, float(original_width - 1.0)))
            top = int(clip(math.floor(y0), 0.0, float(original_height - 1.0)))
            right = int(clip(math.ceil(x0), 0.0, float(original_width - 1.0)))
            bottom = int(clip(math.ceil(y0), 0.0, float(original_height - 1.0)))

            for c in range(channel):
                # H, W, C ordering
                # Note: lerp is shorthand for linear interpolation
                left_top_val = float(src[top * (original_width * channel) + left * (channel) + c])
                right_top_val = float(src[top * (original_width * channel) + right * (channel) + c])
                left_bottom_val = float(src[bottom * (original_width * channel) + left * (channel) + c])
                right_bottom_val = float(src[bottom * (original_width * channel) + right * (channel) + c])
                top_lerp = left_top_val + (right_top_val - left_top_val) * (x0 - left)
                bottom_lerp = left_bottom_val + (right_bottom_val - left_bottom_val) * (x0 - left)
                lerp = top_lerp + (bottom_lerp - top_lerp) * (y0 - top)
                if (lerp < threshold): # Binarize according to threshold
                    dst[y,x] = 0
                else:
                    dst[y,x] = 255
    return dst
                

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.
    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.
        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:
        source_element = child_proxy.get_by_name("source")
        if source_element.find_property('drop-on-latency') != None:
            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

def main(stream_paths, output_folder):
    global perf_data
    perf_data = PERF_DATA(len(stream_paths))
    number_sources = len(stream_paths)

    global folder_name
    folder_name = output_folder
    if path.exists(folder_name):
        sys.stderr.write("The output folder %s already exists. Please remove it first.\n" % folder_name)
        sys.exit(1)

    os.mkdir(folder_name)
    print("Frames will be saved in ", folder_name)
    # 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 streammux \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):
        os.mkdir(folder_name + "/stream_" + str(i))
        print("Creating source_bin ", i, " \n ")
        uri_name = stream_paths[i]
        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.get_request_pad(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)

    print("Creating Pgie \n ")
    pgie = Gst.ElementFactory.make("nvinfer", "primary-inference")
    if not pgie:
        sys.stderr.write(" Unable to create pgie \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")
    if is_aarch64():
        print("Creating nv3dsink \n")
        sink = Gst.ElementFactory.make("nv3dsink", "nv3d-sink")
        if not sink:
            sys.stderr.write(" Unable to create nv3dsink \n")
    else:
        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', "deepstream_customseg_config.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)
    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)

    nvosd.set_property("display_mask", True) # Note: display-mask is supported only for process-mode=0 (CPU)
    nvosd.set_property('process_mode', 0)

    sink.set_property("sync", 0)
    sink.set_property("qos", 0)

    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")
    pipeline.add(queue1)
    pipeline.add(queue2)
    pipeline.add(queue3)
    pipeline.add(queue4)
    pipeline.add(queue5)

    print("Adding elements to Pipeline \n")
    pipeline.add(pgie)
    pipeline.add(tiler)
    pipeline.add(nvvidconv)
    pipeline.add(nvosd)
    pipeline.add(sink)

    print("Linking elements in the Pipeline \n")
    streammux.link(queue1)
    queue1.link(pgie)
    pgie.link(queue2)
    queue2.link(tiler)
    tiler.link(queue3)
    queue3.link(nvvidconv)
    nvvidconv.link(queue4)
    queue4.link(nvosd)
    nvosd.link(queue5)
    queue5.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)

    tiler_sink_pad = tiler.get_static_pad("sink")
    if not tiler_sink_pad:
        sys.stderr.write(" Unable to get src pad \n")
    else:
        tiler_sink_pad.add_probe(Gst.PadProbeType.BUFFER, tiler_sink_pad_buffer_probe, 0)
        # perf callback function to print fps every 5 sec
        GLib.timeout_add(5000, perf_data.perf_print_callback)

    # List the sources
    print("Now playing...")
    for i, source in enumerate(stream_paths):
        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 parse_args():
    parser = argparse.ArgumentParser(prog="deepstream_segmask.py", 
                description="deepstream-segmask takes multiple URI streams as input" \
                    " and re-sizes and binarizes segmentation mask arrays to save to image")
    parser.add_argument(
        "-i",
        "--input",
        help="Path to input streams",
        nargs="+",
        metavar="URIs",
        default=["a"],
        required=True,
    )
    parser.add_argument(
        "-o",
        "--output",
        metavar="output_folder_name",
        default="out",
        help="Name of folder to output mask images",
    )

    args = parser.parse_args()
    stream_paths = args.input
    output_folder = args.output
    return stream_paths, output_folder

if __name__ == '__main__':
    stream_paths, output_folder = parse_args()
    sys.exit(main(stream_paths, output_folder))

Can you share the onnx model? If it is not convenient to make it public, you can send a private message.

I am sorry I cannot do that.

  1. As I mentioned above, nvinfer will convert the video frame format to gray if the value of model-color-format is set to 2, so there is no need to use gstreamer for conversion.

  2. Is your model for semantic segmentation? I think you can refer deepstream-segmentation-test add nvsegvisual to your pipeline.

You can use the following pipeline to fix the code

uridecodebin --> nvstreammux ---> nvinfer --> nvvideoconvert --> nvsegvisual --> nveglglessink
  1. What is the output layer of your model? Usually it is something like conv2d_19/Sigmoid, depending on your model.

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

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.