Laughter BGM has become a typical sound of TikTok, you can hear that sound in many public spots, on the bus, on the metro, in restaurants, on streets and so on. Myself is not a user of TikTok, so when I heard the BGM of TikTok playing over and over again, I used to think the person is watching that video over and over again.
  Recently, my mom watches videos on TikTok and a variety of TikTok symbolic BGM played over and over again. I am a little bit confused and I observe her when she using TikTok. I found out it is not her behavior, it is because TikTok plays videos over and over again automatically, even when she is viewing the comments of the videos. And she apparently doesn't notice that BGM is disturbing when she is absorbed in the funny comments.

  I assume the reasons why TikTok loops videos as follow:
  1. TikTok's videos mostly have a span under a minute, looping video could help the user know the content of it if videos contain much information.
  2. Not only videos, but the community is an important part of TikTok. My mom often takes much more time to read comments than watch short videos. Thus looping video helps the user have a feeling of engagement with this video when they comment or read comments.

  Since the users do not pay attention to the video while reading comments, why not just mute video to not bother others. Looping videos might influence people around by noisy earworms. Therefore I come up with an idea to make TikTok less bothering while maintaining the same immersive experience for users:
  The video should still loop as before but the volume of the video should be lower once the video begins looping. And in each next loop, the volume will be lower than the previous loop. In the fifth loops, the video will be mute.  More specifically, if someone is using TikTok with earphones, the app will not reduce the volume. Instead, if you are playing videos in public, the volume will be lower automatically. And whether the initial volume is not high enough to bother the around, it will still lower when looping.
 At last, it is hard to test if the idea works, but one thing is sure. That is loud noisy BGM played over and over again do disturb others and harm the brand image of TikTok. And We could transfer our design thinking from user-centered to human-centered to solve this.