Playing a video file from your Python program is complicated.

You can use PySide6. Here is an example:

    import sys
    from PySide6.QtWidgets import QApplication, QWidget, QVBoxLayout
    from PySide6.QtMultimedia import QMediaPlayer, QAudioOutput
    from PySide6.QtMultimediaWidgets import QVideoWidget
    from PySide6.QtCore import QUrl


    class VideoPlayer(QWidget):
        def __init__(self):
            super().__init__()
            self.setWindowTitle("Video Player - video.mp4")
            self.resize(800, 600)

            # Layout
            layout = QVBoxLayout()
            self.setLayout(layout)

            # Video widget
            self.video_widget = QVideoWidget()
            layout.addWidget(self.video_widget)

            # Media player
            self.media_player = QMediaPlayer(self)
            self.audio_output = QAudioOutput(self)
            self.media_player.setAudioOutput(self.audio_output)
            self.media_player.setVideoOutput(self.video_widget)

            # Load video file
            self.media_player.setSource(QUrl.fromLocalFile("video.mp4"))

            self.media_player.play()


    if __name__ == "__main__":
        app = QApplication(sys.argv)
        player = VideoPlayer()
        player.show()
        sys.exit(app.exec())