Bi-level/full-color video combination for ubiquitous video communication

Ubiquitous video communication, visually calling anyone at anywhere anytime on any device might be the ultimate goal of modem communication service. As MPEG and H.263 based full-color videos are unable to cover low bandwidth network conditions, we have developed a bi-level/full-color video combination scheme to realize video communication in the whole range of bandwidth conditions. In our scheme, bi-level video works at below 56 Kbps bandwidth range and full-color video works at over 33.6 Kbps bandwidth range. The overlapped bandwidth range 33.6-56 Kbps is used to smoothly switch between bi-level and full-color videos. A bandwidth estimation algorithm is applied to normal bi-level or full-color video status for rate control. A special bandwidth capability probing algorithm is designed to determine the switch of bi-level and full-color videos. Experiments showed that this scheme worked well on video communication systems that ran on PCs, handheld PCs and palm-size PCs