20220828 - CV read video specified frame

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Original link: https://blog.csdn.net/xuezhangjun0121/article/details/122698717

use

import cv2
 
cap = cv2.VideoCapture('XXX.avi')  #返回一个capture对象
cap.set(cv2.CAP_PROP_POS_FRAMES,50)  #设置要获取的帧号
a,b=cap.read()  #read方法返回一个布尔值和一个视频帧。若帧读取成功，则返回True
cv2.imshow('b', b)
cv2.waitKey(1000)

encapsulation

import cv2
 
 
def get_video_png(video_path, png_path, zhen_num=1):
    """
    获取视频封面
    :param video_path: 视频文件路径
    :param png_path: 截取图片存储路径
    :param zhen_num: 指定截取视频第几帧
    :return: 
    """
    vidcap = cv2.VideoCapture(video_path)
    # 获取帧数
    zhen_count = vidcap.get(7)
 
    if zhen_num > zhen_count:
        zhen_num = 1
    print(f"zhen_count = {
      
      zhen_count} | last zhen_num = {
      
      zhen_num}")
 
    # 指定帧
    vidcap.set(cv2.CAP_PROP_POS_FRAMES, zhen_num)
 
    success, image = vidcap.read()
    # n = 1
    # while n < 30:
    #     success, image = vidcap.read()
    #     n += 1
    imag = cv2.imwrite(png_path, image)
 
 
if __name__ == "__main__":
    zhen_num = 1
    video_path = './test.mp4'
    png_path = f'./test_{
      
      zhen_num}.png'
    get_video_png(video_path, png_path, zhen_num)

other

cv2.VideoCapture.get(0) 	视频文件的当前位置（播放）以毫秒为单位
cv2.VideoCapture.get(1) 	基于以0开始的被捕获或解码的帧索引
cv2.VideoCapture.get(2) 	视频文件的相对位置（播放）：0=电影开始，1=影片的结尾。
cv2.VideoCapture.get(3) 	在视频流的帧的宽度
cv2.VideoCapture.get(4) 	在视频流的帧的高度
cv2.VideoCapture.get(5) 	帧速率
cv2.VideoCapture.get(6) 	编解码的4字-字符代码
cv2.VideoCapture.get(7) 	视频文件中的帧数