Question

我必须与多处理器并行地读取视频中的帧。在Python中使用opencv的队列，我的代码出错了。这是我的代码，我不知道我的问题在哪里。

#! /usr/bin/python
import numpy as np
import cv2
import multiprocessing as mp
import time

def read_frames(q1,q2):
        while True :
                frame = q1.get()
                if frame=='Done':
                        break
                R=frame[:,:,0]
                G=frame[:,:,1]
                B=frame[:,:,2]
                y = (np.uint8)((0.299 * R)+ (0.587 *G) +( 0.114 *B))
                q2.put(y)

if __name__ == '__main__':
        q1 = mp.Queue()
        q2 = mp.Queue()
        processes =[mp.Process(target=read_frames, args= (q1,q2)) for i in rang$
        for p in processes:
                         p.start()

        # feed the processes
        # read input file and send to the processes the frames:
        cap = cv2.VideoCapture('gou.avi')
        lines = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
        cols = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
        fps = int(cap.get(cv2.CAP_PROP_FPS))
        fourcc_ver = int(cap.get(cv2.CAP_PROP_FOURCC))
        out = cv2.VideoWriter('output.avi',fourcc_ver, fps, (cols,lines),False)
       # y = np.empty(shape=(lines,cols),dtype=np.uint8)
        while(cap.isOpened()):
                ret, frame = cap.read()
                # as long as new frames are there
                if ret==True:
                        q1.put(frame)
                        if cv2.waitKey(1) & 0xFF == ord('q'):
                                         break
                else:
                     break
        q1.put('Done')



        for p in processes:
                         p.join()
        for p in processes:
                result=[q2.get()]
#       result.sort()
#       results = [r[1] for r in results]
        for i in result:
                out.write(i)
        # Release everything if job is finished
        cap.release()
        out.release()
        cv2.destroyAllWindows()

Answer 1

你可以做的是将所有帧添加到列表[]然后使用列表引用，例如frame = list []，然后按列表上的位置寻址帧：frame [0]或frame [1：4]

与opencv和Python并行读取视频帧

1 个答案: