opencv+python合并视频，可选择起始帧

import cv2

fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('merged_drum.avi',fourcc, 25.0, (1920, 1080))

for path in ['new1.avi','new4.avi','new2.avi']: # 需要合并的视频名称，也可以用os.listdir() 
    cap = cv2.VideoCapture(path)
    # frameToStart = 100
    # cap.set(cv2.CAP_PROP_POS_FRAMES, frameToStart)
    while True:
        ret, frame = cap.read()
        if not ret:
            break
        cv2.imshow('frame', frame)
        ch = 0xFF & cv2.waitKey(30)
        out.write(frame)
        if ch == 27:
            break
    cap.release()  # 关闭相机
out.release()
cv2.destroyAllWindows()

也可以采用视频处理库实现，参考下链接：

https://blog.youkuaiyun.com/gklcsdn/article/details/103091465