Gstreamer 输入到 opencv

Question

From this link I think I may be close but I don't get any errors except for the Nonetype errors when I use the stream.

cap = cv2.VideoCapture("tcpclientsrc host=192.168.1.111 port=5000  ! gdpdepay !  rtph264depay ! avdec_h264 ! videoconvert ! opencvsink sync=false")

I am struggling to find the mistake in the above line. Has anyone accomplished this and mind helping me out.

I have a raspberry pi posting a video stream with gstreamer and can successfully stream it onto an Ubuntu pc with gstreamer in terminal.

Sender:

raspivid -t 999999 -h 720 -w 1080 -fps 25 -hf -b 2000000 -o - | gst-launch-1.0 -v fdsrc ! h264parse !  rtph264pay config-interval=1 pt=96 ! gdppay ! tcpserversink host=192.168.1.111 port=5000

Reciever

gst-launch-1.0 -v tcpclientsrc host=192.168.1.111 port=5000  ! gdpdepay !  rtph264depay ! avdec_h264 ! videoconvert ! autovideosink sync=false

The python script I am trying to get working

import cv2

cap = cv2.VideoCapture('tcpclientsrc host=192.168.1.111 port=5000  ! gdpdepay !  rtph264depay ! avdec_h264 ! '
                           'videoconvert ! appsink')

while True:
    r, frame = cap.read()

    try:
        cv2.imshow('yes', frame)
    except cv2.error as e:
        print(e)

Gives the error OpenCV(3.4.3) /io/opencv/modules/highgui/src/window.cpp:356: error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'imshow'

Answer 1

This posting conversation along with many others helped me formulate a solution. I managed to stream video wirelessly from Raspberry Pi 4 Model B to Jetson Nano with GStreamer and OpenCV using the following:

Launching GStreamer on Raspberry Pi:

raspivid -t 0 -h 720 -w 1080 -fps 25 -hf b 2000000 -o – | gstlaunch-1.0 v fdsrc ! h264parse ! rtph264pay ! config-interval=1 pt=96 ! gdppay ! tcpserversink host=192.168.1.147 port=5000

Receiving video stream in Jetson Nano terminal:

gst-launch-1.0 -v tcpclientsrc host=192.168.1.147 port=5000 ! gdpdepay ! rtph264depay ! h264parse ! avdec_h264 ! videoconvert ! autovideosink sync=false

Receiving video stream in Jetson Nano VideoCapture object:

import cv2
import matplotlib.pyplot as plt

RaspiStreamCam=cv2.VideoCapture(‘tcpclientsrc host=192.168.1.147 port=5000 ! gdpdepay ! rtph264depay ! h264parse ! omxh264dec ! nvvidconv ! video/x-raw, format=BGRx ! videoconvert ! video/x-raw, format=BGR ! appsink’, cv2.CAP_STREAMER)

while True:

    ret, frameRaspiIP=RaspiStreamCam.read()

    cv2.imshow(‘RaspiStreamCam’,frameRaspiIP)

    if cv2.waitKey(1)==ord(‘q’):
        break

RaspiStreamCam.release()

cv2.destroyAllWindows()

Answer 2

你的意思是appsink而不是opencvsink吗？

cap = cv2.VideoCapture("tcpclientsrc host=192.168.1.111 port=5000  ! gdpdepay !  rtph264depay ! avdec_h264 ! videoconvert ! appsink")

Answer 3

To get log messages from gstreamer, set GST_DEBUG before running your Python script. Eg:

GST_DEBUG=4 ./script.py