The episodes have been watched around 20 million times on Bilibili, receiving 400,000 danmu (bullet-words), or short live comments.

For Chen and his team, reading the danmu is a new way to communicate with viewers.

"Unlike TV broadcasts where you receive feedback long after it's released, danmu gives us immediate reviews," Chen says.

Chen also says that viewers on live-streaming sites often watch the same video over and over again, which means that they often pick up on things they may have missed earlier.

Wang believes documentaries shown on live-streaming sites enjoy advantages.

And he says producers in the future will have to do just 80 percent of the work with the rest done by the viewers.

"They will dig up the content that you do not put in the films, which is a new concept for producing."