要注意：

1. 圖片傳視頻要自己設置幀率和分辨率

2.讀取圖片后分辨率要resize為和視頻分辨率一樣才可以

3.寫完.avi視頻后視頻比較大，用ffmpeg將avi視頻壓縮為mp4

import cv2

from cv2 import VideoWriter, VideoWriter_fourcc, imread, resize

import os

from subprocess import call

img_root = '/Users/fanc/Downloads/image/'

out_root = '/Users/fanc/Downloads/image/PeppaPig.avi'

fps = 20 #幀率

size = (640,480)

fourcc = VideoWriter_fourcc(*"MJPG") #支持jpg

videoWriter = cv2.VideoWriter(out_root, fourcc, fps, size)

im_names = os.listdir(img_root)

print(len(im_names))

for im_name in range(len(im_names) - 2):

string = img_root + 'frame' + str(im_name) + '.jpg'

print(string)

frame = cv2.imread(string)

frame = cv2.resize(frame, size) #注意這里resize大小要和視頻的一樣

videoWriter.write(frame)

videoWriter.release()

dir = out_root.strip(".avi")

command = "ffmpeg -i %s.avi %s.mp4" % (dir, dir) #使用ffmped將avi壓縮為mp4,注意兩個的路徑

call(command.split())