如果你不介意在速度上妥协，你可以创建一个python生成器来打开相机并返回frame。

def ReadCamera(Camera):
    while True:
        cap = cv2.VideoCapture(Camera)
        (grabbed, frame) = cap.read()
        if grabbed == True:
            yield frame

现在，当你想处理帧。

for frame in ReadCamera(Camera):
      .....

这工作得很好。除了打开和关闭相机会增加时间。

实现这一点的最好方法是使用线程，下面是我的代码。

"""
This module contains the Streamer class, which is responsible for streaming the video from the RTSP camera.
Capture the video from the RTSP camera and store it in the queue.

NOTE:
    You can preprocess the data before flow from here
"""

import cv2
from queue import Queue
import time
from env import RESOLUTION_X, RESOLUTION_Y,FPS
from threading import Thread

class Streamer:
    def __init__(self,rtsp):
        """
        Initialize the Streamer object, which is responsible for streaming the video from the RTSP camera.
        stream (cv2.VideoCapture): The VideoCapture object.
        rtsp (str): The RTSP url.
        Q (Queue): The queue to store the frame.
        running (bool): The flag to indicate whether the Streamer is running or not.
        Args:
            rtsp (str): The RTSP url.
        """        
        print("Creating Streamer object for",rtsp)
        self.stream = cv2.VideoCapture(rtsp)
        self.rtsp = rtsp
        #bufferless VideoCapture
        # self.stream.set(cv2.CAP_PROP_BUFFERSIZE, 1)
        # self.stream.set(cv2.CAP_PROP_FPS, 10)
        self.stream.set(cv2.CAP_PROP_FRAME_WIDTH, RESOLUTION_X)
        self.stream.set(cv2.CAP_PROP_FRAME_HEIGHT, RESOLUTION_Y)
        self.Q = Queue(maxsize=2)
        self.running = True
        
        
        print("Streamer object created for",rtsp)
    
    def info(self):
        """
        Print the information of the Streamer.
        """        
        print("==============================Stream Info==============================")
        print("| Stream:",self.rtsp,"|")
        print("| Queue Size:",self.Q.qsize(),"|")
        print("| Running:",self.running,"|")
        print("======================================================================")
            
    def get_processed_frame(self):
        """
        Get the processed frame from the Streamer.

        Returns:
            dict: The dictionary containing the frame and the time.
        """        
        if self.Q.empty():
            return None
        return self.Q.queue[0]
    
    
    def release(self):
        """
        Release the Streamer.
        """        
        self.stream.release()
        
    def stop(self):
        """
        Stop the Streamer.
        """        
        print("Stopping",self.stream,"Status",self.rtsp)
        self.running = False
    
    def start(self):
        """
        Start the Streamer.
        """        
        print("Starting streamer",self.stream, "Status",self.running)
        while self.running:
            
            # FOR VIDEO CAPTURE and TESTING FRAME BY FRAME REMOVE THIS COMMENT
            # while self.Q.full():
            #     time.sleep(0.00001)
            ret, frame = self.stream.read()
            # print(frame,ret)
            if not ret:
                print("NO Frame for",self.rtsp)
                continue
            frame =cv2.resize(frame,(RESOLUTION_X,RESOLUTION_Y))
            # exit()
            if not self.Q.full():
                print("Streamer PUT",self.Q.qsize())
                self.Q.put({"frame":frame,"time":time.time()})
                print("Streamer PUT END",self.Q.qsize())
            # exit()
            # time.sleep(1/FPS)
        self.release()
        
        
if __name__ == "__main__":
    streamer = Streamer("rtsp://localhost:8554/105")
    
    thread = Thread(target=streamer.start)
    thread.start()
    
    while streamer.running:
        data = streamer.get_processed_frame()
        if data is None:
            continue
        frame = data["frame"]
        cv2.imshow("frame",frame)
        cv2.waitKey(1)