How to RTSP streaming server with Gstreamer

Python
,
1

Hi,

I’m trying to deploy RTSP streming server with OpenCv and Gstreamer. I have follow the instructions of this link to build from source with Gstreamer.

I’m trying to do that with a simple example.

import os
os.add_dll_directory("C:\\gstreamer\\1.0\\msvc_x86_64\\bin")
os.add_dll_directory("C:\\gstreamer\\1.0\\msvc_x86_64\\lib\\gstreamer-1.0")
import cv2 as cv
import numpy
 
sourceUrl = "http://pendelcam.kip.uni-heidelberg.de/mjpg/video.mjpg"
#command = "appsrc ! videoconvert ! x264enc ! rtph264pay ! udpsink port=5004 host=127.0.0.1 "
command = "appsrc ! video/x-raw, format=BGR ! queue ! videoconvert ! video/x-raw, format=BGRx ! videoconvert ! x264enc speed-preset=veryfast tune=zerolatency bitrate=800 insert-vui=1 ! h264parse ! rtph264pay name=pay0 pt=96 config-interval=1 ! udpsink port=5004 host=127.0.0.1 auto-multicast=0"
 
cap = cv.VideoCapture(sourceUrl)
if not cap.isOpened():
    print("Capture Not Opened")
 
writer = cv.VideoWriter(command, cv.CAP_GSTREAMER, 0, 30, (1280, 720), True)
if not writer.isOpened():
    print("WRITER NOT OPENED!!!!!")
 
if cap.isOpened() and writer.isOpened():
    while True:
        ret, frame = cap.read()
        if not ret:
            print("Not Fram received")
            break
        cv.imshow("frame", frame)
        if cv.waitKey(1) > 0:
            break
   
    cap.release()
    writer.release()

And I have the following output. It seems that Gstreamer cant find dependencies event that I have added dll directories of Gstreamer.

Any idea on how to solve that? At this moment I can’t difference from gstreamer errors on pipeline syntax and gstreamer dependency errors.

(python.exe:6512): GStreamer-WARNING **: 17:18:56.512: Failed to load plugin 'C:\gstreamer\1.0\msvc_x86_64\lib\gstreamer-1.0\gstx264.dll': The specified module could not be found.
This usually means Windows was unable to find a DLL dependency of the plugin. Please check that PATH is correct.
You can run 'dumpbin -dependents' (provided by the Visual Studio developer prompt) to list the DLL deps of any DLL.
There are also some third-party GUIs to list and debug DLL dependencies recursively.
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.512: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GLib-GObject-WARNING **: 17:18:56.512: cannot retrieve class for invalid (unclassed) type '<invalid>'
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.512: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.512: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GLib-GObject-CRITICAL **: 17:18:56.512: g_object_class_find_property: assertion 'G_IS_OBJECT_CLASS (class)' failed
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.512: gst_object_unref: assertion 'object != NULL' failed
 
(python.exe:6512): GLib-GObject-CRITICAL **: 17:18:56.512: g_type_class_unref: assertion 'g_class != NULL' failed
 
(python.exe:6512): GStreamer-WARNING **: 17:18:56.512: Failed to load plugin 'C:\gstreamer\1.0\msvc_x86_64\lib\gstreamer-1.0\gstvideoparsersbad.dll': The specified module could not be found.
This usually means Windows was unable to find a DLL dependency of the plugin. Please check that PATH is correct.
You can run 'dumpbin -dependents' (provided by the Visual Studio developer prompt) to list the DLL deps of any DLL.
There are also some third-party GUIs to list and debug DLL dependencies recursively.
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.512: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GLib-GObject-WARNING **: 17:18:56.525: cannot retrieve class for invalid (unclassed) type '<invalid>'
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.526: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.526: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GStreamer-WARNING **: 17:18:56.530: Failed to load plugin 'C:\gstreamer\1.0\msvc_x86_64\lib\gstreamer-1.0\gstvideoparsersbad.dll': The specified module could not be found.
This usually means Windows was unable to find a DLL dependency of the plugin. Please check that PATH is correct.
You can run 'dumpbin -dependents' (provided by the Visual Studio developer prompt) to list the DLL deps of any DLL.
There are also some third-party GUIs to list and debug DLL dependencies recursively.
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.531: gst_object_unref: assertion 'object != NULL' failed
 
(python.exe:6512): GLib-GObject-CRITICAL **: 17:18:56.532: g_type_class_unref: assertion 'g_class != NULL' failed
 
(python.exe:6512): GStreamer-WARNING **: 17:18:56.535: Failed to load plugin 'C:\gstreamer\1.0\msvc_x86_64\lib\gstreamer-1.0\gstrtp.dll': The specified module could not be found.
This usually means Windows was unable to find a DLL dependency of the plugin. Please check that PATH is correct.
You can run 'dumpbin -dependents' (provided by the Visual Studio developer prompt) to list the DLL deps of any DLL.
There are also some third-party GUIs to list and debug DLL dependencies recursively.
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.537: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GLib-GObject-WARNING **: 17:18:56.537: cannot retrieve class for invalid (unclassed) type '<invalid>'
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.539: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.540: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GLib-GObject-CRITICAL **: 17:18:56.540: g_object_class_find_property: assertion 'G_IS_OBJECT_CLASS (class)' failed
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.541: gst_object_unref: assertion 'object != NULL' failed
 
(python.exe:6512): GLib-GObject-CRITICAL **: 17:18:56.541: g_type_class_unref: assertion 'g_class != NULL' failed
 
(python.exe:6512): GStreamer-WARNING **: 17:18:56.545: Failed to load plugin 'C:\gstreamer\1.0\msvc_x86_64\lib\gstreamer-1.0\gstudp.dll': The specified module could not be found.
This usually means Windows was unable to find a DLL dependency of the plugin. Please check that PATH is correct.
You can run 'dumpbin -dependents' (provided by the Visual Studio developer prompt) to list the DLL deps of any DLL.
There are also some third-party GUIs to list and debug DLL dependencies recursively.
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.546: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GLib-GObject-WARNING **: 17:18:56.547: cannot retrieve class for invalid (unclassed) type '<invalid>'
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.548: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.549: gst_element_factory_get_element_type: assertion 'GST_IS_ELEMENT_FACTORY (factory)' failed
 
(python.exe:6512): GLib-GObject-CRITICAL **: 17:18:56.551: g_object_class_find_property: assertion 'G_IS_OBJECT_CLASS (class)' failed
 
(python.exe:6512): GStreamer-CRITICAL **: 17:18:56.552: gst_object_unref: assertion 'object != NULL' failed
 
(python.exe:6512): GLib-GObject-CRITICAL **: 17:18:56.553: g_type_class_unref: assertion 'g_class != NULL' failed
[ WARN:0@1.151] global cap_gstreamer.cpp:2436 cv::CvVideoWriter_GStreamer::open OpenCV | GStreamer warning: error opening writer pipeline: no property "speed-preset" in element "x264enc"
2

What’s the status? Have you found any solutions regarding it?

I’m also struggling with getting GStreamer to work with Python on Windows.

3

Hi @Amit_Maurya !

My final target was using OpenCv in C# (EmguCv) with Gstreamer to have the posibility to stream video from frames over RTSP.

Finally I did it! The solution is not so obvious because it is not well documented at least for Windows…

For Python you have to import binary directory of Gstreamer because OpenCv is now depending on Gstreamer. I did it like this… Please note that I’m not a Python expert…

import os
os.add_dll_directory("C:\\gstreamer\\1.0\\msvc_x86_64\\bin")
import cv2 as cv

Also you have to include the following directories in Path system environment variable.

C:\gstreamer\1.0\msvc_x86_64\bin
C:\gstreamer\1.0\msvc_x86_64\lib
C:\gstreamer\1.0\msvc_x86_64\include

Please try with this and let me know if this fix your problem. With regards,