Conventional video conferencing systems were premised on connection with ISDN, using telephone numbers as the identifier to specify the communication partner. With the IP network, rather than by the telephone number, the communication partner is specified by an IP address. The IP address, however, can't be used as a semi-permanent identifier like a telephone number, because the IP address may change when a video conferencing terminal is moved to a different location and connected with another network.
If the IP address is changed, the originating side can start, but the IP address of the partner may have changed. If that happens, connection itself is possible, but the originator may be connected to an unexpected party. If the originator knows the IP address of the communication partner in advance, the problem is solved, but that doesn't solve the problem of destination lists, because the lists should be revised whenever IP addresses change. The problem is still not solved.
M2M is the abbreviation for Machine-to-Machine; it is the basic technique for devices to work with each other by exchanging events or to acquire the status of other devices. This technology makes it possible to “control devices remotely,” which was difficult. It also makes it possible to “monitor operation status” and to “recover automatically when a fault occurs.” Ricoh investigated M2M communication control technology for many years to make varied devices work together and to manage devices remotely. Ricoh established a unique method.
The communication module of the wireless carrier is generally used in M2M communication. The Ricoh M2M platform (Figure 1) manages individual devices without requiring a special communication module while using cloud technology. This made it possible for us to develop the portable remote video communication system efficiently as a cloud application.
As each video conferencing terminal can be controlled on the cloud, the user can connect it to the other side of the conference easily, just as was the case with conventional telephone. Even if the IP address changes when the terminal is moved, the CID (contact ID) doesn't change. The address list need not be edited every time. Connection is easy? anytime, anywhere.
In conventional video conferencing systems, the transfer rate (throughput) and zone needed to hold the conference are determined before the conference begins. On the Internet, however, the “best-effort connection” is generally adopted and the throughput continually changes. With the proliferation of wireless networks in recent years, still bigger changes than with wired connections are observed. When the change exceeds the throughput decided when the conference starts, things are fine. But if it goes below, quality may deteriorate to the point that “video stops” and “voice is interrupted.” In the worst case, disconnection may occur, disrupting the conference. On the other hand, if the throughput is set low to avoid quality deterioration and disconnection, the entire conference suffers lower quality.
We need to send and receive quality video and voice on unstable networks, as is the case with wireless communications. This is crucial if we are to provide “communication at anytime, anywhere, for anyone and with anyone” without stress.
As a standard for sending and receiving video under unstable network environments, H.264 SVC (*1) has attracted a lot of attention. SVC is the abbreviation for Scalable Video Codec, and is a standard formally known as “H. 264/SVC Annex G.”
In H.264 SVC, video is divided into multiple qualities to be encoded and then sent and received through multiple channels. When it becomes impossible to secure a sufficient throughput because of a packed network or bad wireless status, a control works to cut the high quality video channel and send and receive a lower quality channel. Even if this control causes the network throughput to fluctuate and narrow, low quality video can continue to display.
With H.264 SVC, the problems resulting from interruption and disconnection are greatly alleviated, even in severe wireless environments where changes of zone are intense. In overcoming the limitations of time and space to achieve stable transmission and reception of video in wireless connections, we made smooth communication possible by combining the M2M platform and H264 SVC. We did so by capitalizing on the advantages of mutual technology.