cv2 ler vídeo

import os
import cv2


# ======================cap.get()========================#
# CV_CAP_PROP_POS_MSEC 视频当前点的毫秒值或视频捕捉的时间戳
# CV_CAP_PROP_POS_FRAMES 下次将被捕获的0基索引的帧
# CV_CAP_PROP_POS_AVI_RATIO 视频文件的相关位置: 0 - start of the film, 1 - end of the film.
# CV_CAP_PROP_FRAME_WIDTH 视频流帧的宽度
# CV_CAP_PROP_FRAME_HEIGHT 视频流帧的高.
# CV_CAP_PROP_FPS 帧率.
# CV_CAP_PROP_FOURCC 4字符编码的编码器.
# CV_CAP_PROP_FRAME_COUNT 视频文件的帧数.
# CV_CAP_PROP_FORMAT 由retrieve()返回矩阵对象的格式 .
# CV_CAP_PROP_MODE 后端指定值指示当前捕捉的模式.
# CV_CAP_PROP_BRIGHTNESS 图像亮度 (只对摄像头).
# CV_CAP_PROP_CONTRAST 图像对比度 (only for cameras).
# CV_CAP_PROP_SATURATION 图像饱和度 (only for cameras).
# CV_CAP_PROP_HUE 色调 (only for cameras).
# CV_CAP_PROP_GAIN 增益(only for cameras).
# CV_CAP_PROP_EXPOSURE 曝光(only for cameras).
# CV_CAP_PROP_CONVERT_RGB 布尔型标记图像是否应该被转换为RGB.
# CV_CAP_PROP_WHITE_BALANCE 白平衡（目前不支持）
# CV_CAP_PROP_RECTIFICATION 立体相机的矫正标记(note: only supported by DC1394 v 2.x backend currently)
# ======================cap.get()========================#
def videoCapture(video_name):
    # 参数表示的摄像头的编号；如果读视频的话将视频文件路径传递进来
    cap = cv2.VideoCapture(0)
    # 获取视频帧的宽度高度
    width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
    height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))

    # 获取视频的FPS
    fps = cap.get(cv2.CAP_PROP_FPS)
    # 获取视频的编码
    fourcc = int(cap.get(cv2.CAP_PROP_FOURCC))

    # 保存成视频格式
    writer = cv2.VideoWriter(video_name, fourcc, fps, (width, height))

    # 判断视频对象是否获取成功，成功则返回True
    while cap.isOpened():
        # 读取视频帧，ret是读取状态，ret为True表示读取成功，如果为False说明读取失败或者是到视频结尾了
        ret, frame = cap.read()
        cv2.imshow('video', frame)
        key = cv2.waitKey(24)
        # 保存视频帧
        writer.write(frame)
        # 如果按下q，退出
        if key == ord('q'):
            break

    # 释放摄像头
    cap.release()
    # 释放所有显示图像的窗口
    cv2.destroyAllWindows()


def video2image():
    # 参数表示的摄像头的编号；如果读视频的话将视频文件路径传递进来
    cap = cv2.VideoCapture(0)
    # 获取视频帧的宽度高度
    width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
    height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))

    # 获取视频的FPS
    fps = cap.get(cv2.CAP_PROP_FPS)
    # 获取视频的编码
    fourcc = int(cap.get(cv2.CAP_PROP_FOURCC))
    print(f"video width:{
      
      width};video height:{
      
      height}; fps:{
      
      fps};fourcc:{
      
      fourcc}")

    # 每一帧之间的间隔
    timeF = int(fps)
    n = 1  # 视频帧总数
    i = 1  # 保存帧总数
    while cap.isOpened():
        # 读取视频帧，ret是读取状态，ret为True表示读取成功，如果为False说明读取失败或者是到视频结尾了
        ret, frame = cap.read()
        if ret:
            break

        # 每间隔timeF帧进行存储一次
        if (n % timeF == 0):
            i += 1
            print(f"保存的第{
      
      i}帧图像")
            save_path = os.path.join('image', f"{
      
      i}.jpg")
            cv2.imwrite(save_path, frame)

        n += 1
        cv2.waitKey(1)

    # 释放摄像头或者视频
    cap.release()