Video Capture — The operating systems of mobile phones provide application programming interfaces (APIs) for video chat software to coordinate camera functionality to capture the content and transmit the content data through a wireless channel (Fig. 3). The software decides the frame rate at which the camera will capture
unique consecutive images and then save them to memory. An appropriate frame rate is very important to maintain a balance between bandwidth, delay, computational power, and user expectations. When users are communicating via sign language, for extreme cases, at least 21 frames/s is recommended in order to support finger spelling. In contrast, various studies suggest that audio and video are perceived as synchronized at minimum 5 frames/s [3]; therefore, that is the frame rate requirement for video chat. But with increasing user expectations, the 5 frames/s frame rate will not suffice.