Accessible Live Video Broadcast With Realtime Caption

From the sixth national population census and the second national sampling census on disabled people, there are about20.54million people suffering from the hearing impairment, leading the five major disabilities in China (Visual impairment, hearing impairment, extremity disability, mentally retarded etc.). With hearing impairment, vision is their main way of perception and information accessibility becomes an issue for them. For instance, most television stations in China do not provided real-time caption and this leads to severe accessibility issues for hearing impairment. So, providing real-time caption for live broadcasts is very important.To provide real time caption for millions of users with hearing impairment in the Internet, the main challenges are real-time caption generation and the load balancing of caption server. Two key technologies are combined to address the two issues. First, we exploit the short delay between the network live broadcast and the live TV broadcast to generate the real time caption. The generation system consists of three parts, i.e. caption client for monitoring the caption script and real time caption generation, caption server for caption storage and generation, communication module based on WCF (Windows Communication Foundation). Second, to achieve load balancing in practical network model, a Nginx-based solution is proposed in this paper. The simulation experiments show that the solution works well for massive accesses.The first practical use of our system is in the2012Spring Festival Gala. During the5hours’broadcast, more than30,000words were typed, with an accuracy higher than98percent. There were about0.14million users enjoying the online live with caption, and about0.43million page clicks occurred in total. Our system is of great significance for promoting the Web surfing experience for users with hearing impairment.