Browse media with PyQT6

I wanted to create a browsing media file with QT so I wrote that :

import sys
import random
import os
import time
from PyQt6 import QtCore, QtWidgets, QtGui
from PyQt6.QtWidgets import QLabel, QPushButton,QSizePolicy, QFileDialog,QHBoxLayout, QVBoxLayout, QSlider, QInputDialog, QMainWindow, QApplication
from PyQt6.QtGui import QPixmap, QShortcut, QKeySequence, QMovie
from PyQt6.QtCore import Qt,QUrl, QTimer, QSettings, QSize, QPoint
from PyQt6.QtMultimediaWidgets import QVideoWidget
from PyQt6.QtMultimedia import QMediaPlayer, QAudioOutput


# Subclass QMainWindow to customize your application's main window
class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()


        self.posi = 0
        #path
        if (len( sys.argv ) > 1):
            self.folderpath = sys.argv[1]
        else:
            self.folderpath = "your folder contaianing the files" #<============ DONT FORGET TO FINISH THE PATH WITH /
        #pathlist
        self.img_list = os.listdir(self.folderpath)
        print(self.img_list)

        self.setWindowTitle("My App")

        self.mediaPlayer = QMediaPlayer(None)
        self.videoWidget = QVideoWidget()
        self.audio_output = QAudioOutput()

        self.mediaPlayer.setVideoOutput(self.videoWidget)
        self.mediaPlayer.setAudioOutput(self.audio_output)
        self.audio_output.setVolume(50)
        self.mediaPlayer.setLoops(-1)

        self.mediaPlayer.setSource(QUrl(self.folderpath+self.img_list[0]))
        self.mediaPlayer.play()

        # Set the central widget of the Window.
        self.setCentralWidget(self.videoWidget)

        #shortcut
        self.shortcut_right = QShortcut(QKeySequence("Right"),self)
        self.shortcut_right.activated.connect(self.button_right_clicked)

    def button_right_clicked(self, *args):#when navigate right
        print("---->")
        try:
            self.img_list[self.posi+1]
        except IndexError:
            self.posi = 0
        else:
            self.posi = self.posi + 1
        self.mediaPlayer.setSource(QUrl(self.folderpath+self.img_list[self.posi]))
        self.mediaPlayer.play()


app = QApplication(sys.argv)

window = MainWindow()
window.show()

app.exec()

But sometimes when use the method "button_right_clicked" the program shutdown without any error or closing event. This method is used to navigate through the list of files in the source folder. I'm using only mp4 file for now.

The error comes from this line i presume : self.mediaPlayer.setSource(QUrl(self.folderpath+self.img_list[self.posi]))

Because when i try to set the same media (img_list[0]) file as source, instead of using index self.posi, it doesn't crash.

According to the documentation, it seems to be the approriate way of swapping between media.

Any idea how to solve this problem ?