Towards Portable Multi-camera High Definition Video Capture Using Smartphones

摘要

Real-time tele-immersion requires low latency and synchronized multi-camera capture. Prior high definition (HD) capture systems were bulky. We investigate the suitability of using flocks of smartphone cameras for tele-immersion. Smartphones integrate capture and streaming into a single portable package. However, they archive the captured video into a movie. Hence, we create a sequence of H.264 movies and stream them. Capture delay is reduced by minimizing the number of frames in each movie segment. However, fewer frames reduces compression efficiency. Also, smartphone video encoders do not sacrifice video quality to lower the compression latency or the stream size. On an iPhone 4S, our application that uses published APIs streams 1920x1080 videos at 16.5 fps with a delay of 712 ms between a real-life event and displaying an uncompressed bitmap of this event on a local laptop. Note that the bulky Cisco Tandberg required 300 ms delay. Stereoscopic video from two unsynchronized smartphones also showed minimal visual artifacts in an indoor setting.