python-opencv：在视频中显示进度条等opencv快速入门_python tk opencv视频进度条

上期回顾

上期我们主要是针对在视频中选择实时的fps，这期主要是讲讲用opencv显示进度条。这期也是在上期的基础上添加的代码

进度条

下面代码是上期代码中增加的效果

# coding=gbk
import time
import cv2
 
def nothing(emp):
    pass
#设置窗口名称
cv2.namedWindow('frame')
cap = cv2.VideoCapture("D:\\jc\\Myself\\video\\Hacker_glasses_07_Videvo.mov")  # 读取文件
start_time = time.time()
#用于记录帧数
counter = 0
# 获取视频宽度
frame_width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
# 获取视频高度
frame_height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
#视频平均帧率
fps = cap.get(cv2.CAP_PROP_FPS)
# 获取视频帧数
frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
loop_flag = 0
pos = 0
# 新建一个滑动条
cv2.createTrackbar('time', 'frame', 0, frames, nothing)
while (True):
    if loop_flag == pos:
        loop_flag = loop_flag + 1
        cv2.setTrackbarPos('time', 'frame', loop_flag)
    else:
        pos = cv2.getTrackbarPos('time', 'frame')
        loop_flag = pos
        cap.set(cv2.CAP_PROP_POS_FRAMES, pos)
    ret, frame = cap.read()
    # 键盘输入空格暂停，输入q退出
    key = cv2.waitKey(1) & 0xff
    if key == ord(" "):
        cv2.waitKey(0)
    if key == ord("q"):
        break
    counter += 1  # 计算帧数
    if (time.time() - start_time) != 0:  # 实时显示帧数
        cv2.putText(frame, "FPS {0}".format(float('%.1f' % (counter / (time.time() - start_time)))), (500, 50),
                    cv2.FONT_HERSHEY_SIMPLEX, 2, (0, 0, 255),
                    3)
        src = cv2.resize(frame, (frame_width // 2, frame_height // 2), interpolation=cv2.INTER_CUBIC)  # 窗口大小
        cv2.imshow('frame', src)
        print("FPS: ", counter / (time.time() - start_time))
        counter = 0
        start_time = time.time()
    time.sleep(1 / fps)  # 按原帧率播放
cap.release()
cv2.destroyAllWindows()

下面代码是单独创建进度条的效果

import cv2
 
 
def nothing(emp):
    pass
video = 'D:\\jc\\Myself\\video\\Hacker_glasses_07_Videvo.mov'
cv2.namedWindow('video')
cap = cv2.VideoCapture(video)
frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
loop_flag = 0
pos = 0
cv2.createTrackbar('time', 'video', 0, frames, nothing)
 
while 1:
    if loop_flag == pos:
        loop_flag = loop_flag + 1
        cv2.setTrackbarPos('time', 'video', loop_flag)
    else:
        pos = cv2.getTrackbarPos('time', 'video')
        loop_flag = pos
        cap.set(cv2.CAP_PROP_POS_FRAMES, pos)
    ret, img = cap.read()
    cv2.imshow('video', img)
    if cv2.waitKey(1) & loop_flag == frames:
        break
cap.release()
cv2.destroyAllWindows()

讲解

在我们代码中需要注意，最开始创建窗口时的名称，以及创建滑动条的名称、展示出来的名称都要保持一致。