A video application executing on a client device allows a user to modify video data captured by the client device. The video application allows the user to transmit the video data to a viewing client device for presentation to a viewing user. For example, the video application transmits the video data to an online system, which transmits the video data to the viewing client device. The viewing user provides a request to modify the video data to the viewing client device, which transmits the request to the online system. Based on the request from the viewing client device, the online system identifies a modification to the video data to the client device, which modifies the captured video data accordingly. The modified video data is provided from the client device to the viewing client device via the online system.