It depends on the type of safety education courses. In general, most video files on the network are in flash format, including flv, which can be played at any time on the network and can be played in the background on any computer at present. However, one kind of files, such as video files published on some websites, only support instant playback. This kind of file cannot be played in the background, that is, the file playing window can only be placed in the front window of the computer. If you click on other interfaces during playback, playback will be terminated. It's best to use multiple computers to play different files at the same time, which can save time.