python - 在 python 中将 gstreamer 管道转换为 opencv

Question

我使用以下 gstreamer 命令创建了一个网络流:

发件人:

gst-launch-1.0 -v videotestsrc ! video/x-raw,framerate=20/1 ! videoscale ! videoconvert ! x264enc tune=zerolatency bitrate=500 speed-preset=superfast ! rtph264pay ! udpsink host=X.X.X.X port=5000

接收者:

gst-launch-1.0 -v udpsrc port=5000 caps = "application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, payload=(int)96" ! rtph264depay ! decodebin ! videoconvert ! autovideosink

这很好用。我现在想在 python 脚本中包含接收器端的流。在脚本中我想用 opencv 做一些视频处理。

有谁知道如何转换所描述的管道，以便它可以与 opencv 一起使用？

谢谢!

编辑1:

发现这应该有效:

cap = cv2.VideoCapture("udpsrc port=5000 ! application/x- rtp,media=video,payload=26,clock-rate=90000,encoding-name=H264, payload=96 ! rtph264depay ! decodebin ! videoconvert ! appsink", cv2.CAP_GSTREAMER)

我收到以下错误:

OpenCV Error: Assertion failed (size.width>0 && size.height>0) in imshow, file /home/nvidia/build-opencv/opencv/modules/highgui/src/window.cpp, line 331 Traceback (most recent call last): File "launchstream_ip.py", line 13, in <module> cv2.imshow('frame', frame) cv2.error: /home/nvidia/build-opencv/opencv/modules/highgui/src/window.cpp:331: error: (-215) size.width>0 && size.height>0 in function imshow

Answer 1

import numpy as np
import cv2
from multiprocessing import Process

def send():
    cap_send = cv2.VideoCapture('videotestsrc ! video/x-raw,framerate=20/1 ! videoscale ! videoconvert ! appsink', cv2.CAP_GSTREAMER)
    out_send = cv2.VideoWriter('appsrc ! videoconvert ! x264enc tune=zerolatency bitrate=500 speed-preset=superfast ! rtph264pay ! udpsink host=127.0.0.1 port=5000',cv2.CAP_GSTREAMER,0, 20, (320,240), True)

    if not cap_send.isOpened() or not out_send.isOpened():
        print('VideoCapture or VideoWriter not opened')
        exit(0)

    while True:
        ret,frame = cap_send.read()

        if not ret:
            print('empty frame')
            break

        out_send.write(frame)

        cv2.imshow('send', frame)
        if cv2.waitKey(1)&0xFF == ord('q'):
            break

    cap_send.release()
    out_send.release()

def receive():
    cap_receive = cv2.VideoCapture('udpsrc port=5000 caps = "application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, payload=(int)96" ! rtph264depay ! decodebin ! videoconvert ! appsink', cv2.CAP_GSTREAMER)

    if not cap_receive.isOpened():
        print('VideoCapture not opened')
        exit(0)

    while True:
        ret,frame = cap_receive.read()

        if not ret:
            print('empty frame')
            break

        cv2.imshow('receive', frame)
        if cv2.waitKey(1)&0xFF == ord('q'):
            break

    cap_receive.release()

if __name__ == '__main__':
    s = Process(target=send)
    r = Process(target=receive)
    s.start()
    r.start()
    s.join()
    r.join()

    cv2.destroyAllWindows()