The COVID-19 pandemic prevents us from enjoying live performances. On the other hand, commercial audiovisual transmission systems, such as live viewing systems, have become more popular and have been increasing. The APRICOT: (APplause for Realistic Immersive Contents Transmission) system was developed and used in some trials to enhance the reality for live viewing. This paper describes an applause sound extraction method for automation of applause sound transmission and a simulation experiment using the sound source recorded live at the venue to assess the applause sound extraction performance. We used an adaptive filter to model the room transfer function. In addition, we designed the inverse filter to emphasize applause sounds and extracted them. The experimental evaluation showed that the system extracted the applause sounds almost correctly under various conditions from the performance sound source.