這裏實現的是從一段視頻中每10幀讀取第10幀圖片，代碼如下：

# -*- coding:utf-8 -*-
#視頻中按序列提取幀，獲得訓練數據
import cv2
import os

video_src_path = "D:/mtcnn"
video_save_path = "D:/mtcnn/mydata"

videos = os.listdir(video_src_path)
videos = filter(lambda x : x.endswith("mp4") , videos)

for each_video in videos:
    print each_video

    each_video_name , _ 
 
= each_video.split(‘.‘)
    m = video_save_path + ‘/‘ + each_video_name

    if(os.path.exists(m) == False):
        os.mkdir(m)  #新建“D:/mtcnn/Mathbook_pic/Mathbook/”文件夾
    each_video_save_full_path = os.path.join(video_save_path, each_video_name) + ‘/‘

    each_video_full_path = video_src_path + ‘
 
/‘ + each_video
    print each_video_full_path
    cap = cv2.VideoCapture(each_video_full_path)

    if False == cap.isOpened():
        print ‘open video failed‘  
    else:
        print ‘open video succeeded‘

    count = 0   #統計幀數
    frame_gap = 10  #間隔為10幀，每個10幀讀取第10幀
    success = True
    i 
 
= 0
    #每隔10幀讀取一幀
    while(success):
        success , frame = cap.read()
        i = i + 1
        if(i == frame_gap):  #每個10幀讀取第10幀
            print success
            #print ‘Read a new frame:‘ , success
            params = []
            params.append(int(cv2.IMWRITE_JPEG_QUALITY))
            params.append(95)
            cv2.imwrite(each_video_save_full_path + each_video_name + ‘_%d.jpg‘ % count , frame , params)
            count = count + 1
            i = 0

    cap.release()
print ‘OK！‘

註意的是，對於cv2庫的VideoCapture函數，如果之前使用的是Pip 安裝的opencv的python庫，則沒有安裝FFmPeg，會導致無法正常打開視頻，需要按下面步驟進行操作：

參考鏈接：http://blog.csdn.net/yedasha/article/details/78128345

從一段視頻中按幀提取圖片