逐帧播放/停止视频文件，在tkinter中

Question

我正在尝试使用python 3在覆盆子pi上启动/停止tkinter中的视频文件。

我需要视频从头开始，每次红外传感器是低(损坏)和停止传感器再次高。理想情况下，视频应该在一个tkinter画布内，以便我可以在屏幕上同时显示其他元素(例如，加载栏)。

我设法让所有的东西都运行了，除了视频，它会在检测到传感器时立即运行，但它会冻结所有其他进程(例如加载条)，并且在传感器处于高电平时不会停止。

以下是代码的简化(和未检查)版本，让您了解总体结构(实际代码要长得多)：

import tkinter as TK
import RPi.GPIO as GPIO
import os

GPIO.setmode(GPIO.BCM)
GPIO.setup(14, GPIO.IN)

class App:
    def __init__(self, root):
        self.root = root
        self.root.config(background = 'black', cursor = 'none')
        self.background = TK.Canvas(root, width = 1024, height = 600, bg = 'black')
        self.background.pack()

        self.ext = 0
        self.trial = 0
        self.infrared()

    def infrared(self):
        if (GPIO.input(14) == False):
            self.makebar()

            if (self.ext == 0):
                self.runvideo()

        else:
            os.system("killall omxplayer.bin")
            self.ext = 0

        self.root.after(16, self.infrared)

    def runvideo(self):
        os.system("omxplayer /home/pi/Desktop/testvideo.m4v")

    def makebar():
        self.stimulus_rect = TK.Canvas(root, width = 1024, height = 50, bg= 'white')
            if self.ext < 1000
                self.ext = self.ext + 10
                self.stimulus_rect.create_rectangle(0, 0, self.ext, 50, fill="red")
                self.stimulus_rect.place(x=0, y=0, anchor="new")
            else:
                self.trial = self.trial + 1
                self.ext = 0

root = TK.Tk()
App(root)
root.mainloop()

根据我在网上所能找到的: 1) tkinter可能会与opencv结合使用来实现这一点，但在树莓pi上安装opencv看起来并不是一个简单的操作；2)一般来说，涉及"os“的选项似乎注定无法实现我想要实现的目标。

我找不到一种干净的方法来做这件事。我的理想场景是将视频帧一个接一个地加载到画布中，并以60 at (屏幕频率)加载。然后，我将以完全相同的频率检查传感器，如果传感器没有损坏，则防止加载下一帧。在伪代码中，这将如下所示

def infrared(self):
    if (GPIO.input(14) == False):
        self.makebar()

        if (self.ext == 0):
            self.runvideo()

    else:
        self.video.stop
        self.ext = 0
        self.frame = 0

    self.root.after(16, self.infrared)

def runvideo(self):
    self.frame = self.frame + 1
    video.run("testvideo.m4v", self.frame)

关于如何在树莓派的tkinter中实现这一点有什么想法吗？

感谢蚂蚁

Answer 1

经过一周的研究、试验和错误，这就是我目前如何实现我所需要的(用伪代码)：

#### PSEUDOCODE ####         
from subprocess import Popen  # this library is used to open the video file


class App:
    def __init__(self, root):
        self.moviestart = False

    self.movieduration = 130000
    self.movie = "/home/pi/Desktop/test.mp4"

    def infrared(self):
        if (GPIO.input(IR) == False):
            if not self.moviestart:
                self.makevideo()  # Call the function to start the video
            self.moviestart = True  # Flag that the video has started
            self.moviestop = False  # Flag that the video is currently playing
            self.root.after(self.videoduration,
                            self.stopvideo)  # manually call the stop video function 
            # to stop the video after 13 seconds (video's length). 
            # I could not find a more elegant way of doing this, unfortunately. 
        else:
            self.clear_screen()

    self.root.after(self.refreshIR, self.infrared)


def makevideo(self):
    # popen will open the movie in a window of the size I specified, 
    # so that other element from tkinter can be placed on top of the movie window
    omxc = Popen(['omxplayer', self.movie, '--win', "0 30 800 450"])


def stopvideo(self):
    self.moviestart = False  # flag that movie has been stopped       
    if (self.moviestop == False):  # check if the movie is currently playing
        try:  # this is a cheap workaround other problems I had, do not try this at home
            os.system('killall omxplayer.bin')  # this literally kills any omxplayer instance 
            # currently open
            self.moviestop = True  # flag that the movie is not playing at the moment 
        except:
            pass

我希望这能对其他有类似问题的人有所帮助。如果我找到更好的解决方案，我会更新答案。就目前而言，这已经足够好了。