如何在播放视频时打开和关闭omxplayer (Python/Raspberry Pi) ?

Using a Raspberry Pi and some push buttons I want to control video playback. When someone presses a button the corresponding video plays. The buttons work great. When you press a button the video plays, but when you press a different button or the same button it opens the video without closing the video that was currently playing. I've been searching a while to fix this. I'm pretty new to Python so please keep it as simple as possible. In the code below I'm trying to accomplish it using multithreading. I wasn't able to close the thread though when another thread starts. I am able to close the video after it plays for 10 seconds, but I can't move the quit command anywhere else to close other videos: playSippycup.stdin.write('q')Using a Raspberry Pi and some push buttons I wa