要注意：

1. 图片传视频要自己设置帧率和分辨率

2.读取图片后分辨率要resize为和视频分辨率一样才可以

3.写完.avi视频后视频比较大，用ffmpeg将avi视频压缩为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 #帧率

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) #注意这里resize大小要和视频的一样

videoWriter.write(frame)

videoWriter.release()

dir = out_root.strip(".avi")

command = "ffmpeg -i %s.avi %s.mp4" % (dir, dir) #使用ffmped将avi压缩为mp4,注意两个的路径

call(command.split())