Python+QTimer计时器实现摄像头视频的播放和暂停

import cv2
import sys
from PyQt5 import  QtWidgets
from PyQt5.QtCore import Qt, QTimer
from PyQt5.QtGui import QPixmap,  QImage
from PyQt5.QtWidgets import QWidget,  QHBoxLayout, QPushButton, QVBoxLayout, QLabel
 
 
class UI_FROM(QWidget):
    def __init__(self):
        super(UI_FROM, self).__init__()
        self.resize(800, 600)
        self.timer_camera = QTimer()
        self.vl = QVBoxLayout(self)
        self.hl = QHBoxLayout(self)
        btn1 = QPushButton('播放')
        btn1.clicked.connect(self.ShowCamera)
        self.hl.addWidget(btn1)
        btn2 = QPushButton('暂停')
        btn2.clicked.connect(self.timer_camera.stop)
        self.hl.addWidget(btn2)
        self.vl.addLayout(self.hl)
        self.label = QLabel(self)
        self.label.setGeometry(20, 20, 640, 480)
        self.label.setStyleSheet("QLabel{background: black;}")
        self.label.setAlignment(Qt.AlignTop)
        self.label.setAlignment(Qt.AlignLeft)
        self.label.setFrameShape(QtWidgets.QFrame.Box)
        self.label.setScaledContents(True)
        self.vl.addWidget(self.label)
        self.cap = cv2.VideoCapture(0)
        print('摄像头是否开启： {}'.format(self.cap.isOpened()))
 
    def Stop(self):
        self.timer_camera.stop()
 
    def ShowCamera(self):
        self.timer_camera.start(100)
        self.timer_camera.timeout.connect(self.ShowData)
 
    def ShowData(self):
        self.ret, color_frame = self.cap.read()
        if self.ret :
            color_frame = cv2.flip(color_frame, 1)
            cv2.waitKey(1)
            im = cv2.cvtColor(color_frame, cv2.COLOR_RGB2BGR)
            img = QImage(im.data, im.shape[1], im.shape[0], QImage.Format_RGB888)
            self.label.setPixmap(QPixmap.fromImage(img))
        else:
            self.cap.release()
            self.timer_camera.stop()
 
if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    ui =UI_FROM()
    ui.show()
    sys.exit(app.exec_())