 HD Simulcast is a Emblaze-VCON branded set of multicast and unicast streaming methods found on Emblaze-VCON conferencing systems. Both "multicast" and "unicast" send streams of video, audio and data across a network - either a closed network (like a corporate LAN) or an open network (like the Internet). With Emblaze-VCON HD Simulcast the unicast streams contain advanced features such as downspeeding and transcoding. Downspeeding is important when people in a point-to-point conference want to simultaneously stream that conference. HD Simulcast will allow the conference (multipoint or point-to-point) to be at a high data rate (say 1Mbps) while streaming the conference is at a more Internet-appropriate bandwidth (say 128kbps.) Transcoding is a feature that allows the interactive conference to use a higher resolution (CIF) while the viewers are seeing it at a lower resolution (QCIF).
Additionally, with HD Simulcast, when a user is transmitting data and video simultaneously, those 2 separate streams can be unicast or multicast so that all participants can see the data and the video. Here is an example of a conference that is being watched with the HD WEB interface viewer where both data and video are being sent.
Multicast Streaming:
With HD Simulcast, a conference can be multicasted across the corporate network to any Emblaze-VCON Broadcast Viewer , HD WEB interface viewer, or any other multicast viewer that has an integrated SDP listener. The SDP listener enables the viewer to detect that a broadcast is taking place.
The benefit of the IP multicast protocol is that there is only one stream being sent over the network, no matter how many people are viewing the stream. It is the most bandwidth efficient method of streaming, but the network must be multicast-enabled.
Unicast Streaming:
With HD Simulcast, a conference can be streamed using the Unicast streaming method over the Internet or corporate network. The unicast streaming method is preferred when the network is not multicast enabled, like the Internet where the routers are set not to propagate the multicast packets.
With unicast, the session is not announced using SDP, and users would browse to the system's IP address and view the stream there using the HD WEB interface viewer.
Multi-Unicast Streaming:
This method of streaming is a version of the Unicast streaming mentioned above. When multi-unicast streaming is being used, it means that multiple, separate streams are being generated for each user, and more than one person can view the unicast. For example, up to 25 streams can be viewed from the unicast during a corporate multicast. And up to 10 streams can be viewed from the unicast when there is a point-to-point or multipoint call being streamed. Below is an example of a multi-unicast conference.
Emblaze-VCON Interactive Multicast
This method of streaming is a hybrid of the IP multicast protocol and is a unique streaming method invented by Emblaze-VCON. Emblaze-VCON Interactive Multicast uses the bandwidth-efficient IP Multicast protocol, but adds a layer of interactivity, where the "chair" or host of the multicast can virtually move the podium to any other participant, allowing interaction between all on the call. To read more about Emblaze-VCON's Interactive Multicast, click here .
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