Python tkinter 的视频播放器，当我暂停视频时，我无法重新播放 [英] Video player by Python tkinter, When I pause video, I cannot re-play
问题描述
我正在创建 GUI 来播放视频文件.问题是当我暂停视频时，播放按钮无法重新播放该视频，我必须再次选择视频文件.
I am creating GUI to play video files. The problem is that when I pause video, Play button cannot re-play that video, and I have to select video file again.
注意:因为我想在同一个 tkinter 窗口中显示视频，所以我不使用 OpenCV imshow 命令.相反，我使用window.after"方法.
Note: Since I want to show video in the same tkinter window, I don't use OpenCV imshow command. Instead, I am using "window.after" method.
以下是我的代码:
我尝试使用self.pause"变量来控制暂停状态.当我单击暂停按钮时，这个布尔变量变为 True.但是，当我再次单击播放"按钮时，我找不到合适的位置将其设为 False.
I try to use "self.pause" variable to control pause status. When I click Pause button, this Boolean variable becomes True. However, I couldn't find suitable place to make it False when I click Play button again.
from tkinter import *
from tkinter import messagebox
from tkinter import filedialog
import PIL.Image, PIL.ImageTk
import cv2
class videoGUI:
def __init__(self, window, window_title):
self.window = window
self.window.title(window_title)
top_frame = Frame(self.window)
top_frame.pack(side=TOP, pady=5)
bottom_frame = Frame(self.window)
bottom_frame.pack(side=BOTTOM, pady=5)
self.pause = False # Parameter that controls pause button
self.canvas = Canvas(top_frame)
self.canvas.pack()
# Select Button
self.btn_select=Button(bottom_frame, text="Select video file", width=15, command=self.open_file)
self.btn_select.grid(row=0, column=0)
# Play Button
self.btn_play=Button(bottom_frame, text="Play", width=15, command=self.play_video)
self.btn_play.grid(row=0, column=1)
# Pause Button
self.btn_pause=Button(bottom_frame, text="Pause", width=15, command=self.pause_video)
self.btn_pause.grid(row=0, column=2)
self.delay = 15 # ms
self.window.mainloop()
def open_file(self):
self.pause = False
self.filename = filedialog.askopenfilename(title="Select file", filetypes=(("MP4 files", "*.mp4"),
("WMV files", "*.wmv"), ("AVI files", "*.avi")))
print(self.filename)
# Open the video file
self.cap = cv2.VideoCapture(self.filename)
self.width = self.cap.get(cv2.CAP_PROP_FRAME_WIDTH)
self.height = self.cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
self.canvas.config(width = self.width, height = self.height)
def get_frame(self): # get only one frame
try:
if self.cap.isOpened():
ret, frame = self.cap.read()
return (ret, cv2.cvtColor(frame, cv2.COLOR_BGR2RGB))
except:
messagebox.showerror(title='Video file not found', message='Please select a video file.')
def play_video(self):
# Get a frame from the video source, and go to the next frame automatically
ret, frame = self.get_frame()
if ret:
self.photo = PIL.ImageTk.PhotoImage(image = PIL.Image.fromarray(frame))
self.canvas.create_image(0, 0, image = self.photo, anchor = NW)
if not self.pause:
self.window.after(self.delay, self.play_video)
def pause_video(self):
self.pause = True
# Release the video source when the object is destroyed
def __del__(self):
if self.cap.isOpened():
self.cap.release()
##### End Class #####
# Create a window and pass it to videoGUI Class
videoGUI(Tk(), "EnJapan")
如果我在play_video"函数中编写以下代码:
If I write following code in "play_video" function:
self.pause = False
暂停按钮不起作用.因为window.after"方法会自动调用play_video"函数并使self.pause"为False.因此，暂停按钮将不起作用.
Pause button will not work. Because "window.after" method calls "play_video" function automatically and make the "self.pause" as False. Therefore, Pause button will have no effect.
推荐答案
问题:暂停按钮无效.
参考:
注册在给定时间后调用的回调.
Registers an callback that is called after a given time.
Tkinter.Widget.after_cancel-method - after_cancel(id)
取消回调.
要取消 self.play_video 的所有已排队events，请更改以下内容:
To cancel the allready queued events for self.play_video change the following:
def play_video(self):
...
if self.pause:
self.window.after_cancel(self.after_id)
else:
self.after_id = self.window.after(self.delay, self.play_video)
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