Starbak Communications Inc.’s Torrent videoconferencing gateway converts a videoconference into streaming media. This would let a manager, for example, make an announcement by videoconference, while others not on the call could watch it later. We liked Torrent’s architecture but the viewing experience needs refinement.
The Torrent VCG is a 1U-high server running Red Hat Inc.’s Linux 2.4 and a combination of third-party licensed and Starbak-written applications for streaming and videoconferencing. The server contains built-in gigabit Ethernet connections, and has options for Networked File System-mounted storage devices.
Using a serial console interface, an administrator can assign an IP address automatically (through Dynamic Host Configuration Protocol) or manually. Other settings, such as H.323, streaming server and user configuration, are handled through the VCG Web interface. Registering with any H.323-compliant gatekeeper is easy, and ensures that Torrent is a network-based service, accessible and managed like other videoconferencing network resources, such as gateways and multipoint conferencing units (MCU).
Password-protected accounts can be created for business units or entire companies. Each account is assigned virtual “lines,” up to a maximum of 10 H.323 ports per server. Through gatekeeper call routing, each call it receives or originates uses the next available port.
Creating and viewing sessions
Torrent users can initiate calls with any H.323-compliant device. During the call setup, the user selects the media and tools that will be incorporated into the final presentation window. Options include video and audio, video and audio with slides, and all of the above with chat.
Users registered to the same or a neighbour gatekeeper can establish a video call to a specific line from their videoconferencing terminal by entering the alias of a specific line or to the next available H.323 port by entering the IP address of the VCG server.
For conferences that includes slides, the uploading process is straightforward and sufficiently automated. Each slide is converted to a JPEG on the server and advanced manually once a call begins. The call-initiation process was reliable, and we never had a call fail. We even maintained a call for more than three hours.
We encountered some poor video quality on a few of our calls, which the terminal diagnostics attributed to packet loss. When notified that we were having a call-quality issue, Starbak’s technical assistance was responsive – potential errors in the server and network were identified and quickly resolved.
When we used the VCG to record a conference call with another videoconferencing system, the conference experience was confusing. The MCU interpreted the VCG as a full call participant and included it in the tiled layout, yet it was not contributing to the call and could not be muted.
Because the VCG’s conversion of a live interactive session to a stored or Webcast experience is not transcoded, audiences watching a VCG-streamed conference receive the stream at precisely the same data rate as it is created. This avoids introducing additional delay and visual or auditory artefacts in the media stream.
But it also has a significant drawback. When a videoconference is encoding at 384Kbps or 512Kbps, and 10 people are watching on a 10Mbps network segment, it can get saturated quickly. To alleviate this potentially high load on an enterprise network, the Torrent user or administrator can select to multicast a stream.
The WMF stream viewing interface needs improvement in many areas. While watching a live media stream with slides, synchronization doesn’t always occur, especially if you use the navigation bar to pause, stop, rewind or fast forward.
The viewer window has a progress bar, but we would prefer to see total file duration and a chronometer indicating elapsed time, and possibly an index of the slides to permit topical navigation. The video window size also is locked down in the viewer to a quarter of the screen – an adjustable window size would be a nice option. The viewer’s presentation layer also needs to perform some pre-display resolution tests. Some JPEGs produced by the conversion of PowerPoint slides did not fit on the screen in the window provided, and were not resized for the display.
Session and server management and administration
When the Torrent is in a call, the management interface lets administrators, call initiators and moderators view call-specific information, including compression algorithms in use, presentation format, duration, record on/off and the number of viewers in different formats receiving the stream. With one mouse-click, VCG account users can begin or end recording of an active session to the disk. A window in the call centre view indicates the bandwidth usage of a selected call in real time. Overall, the call centre was very useful, but occasionally we encountered what we interpreted to be errors in the embedded Java applet.
The administrator or account user also can see relevant server usage statistics, including streaming bandwidth summary, active stream list, audience totals and active multicast lists. File management is easy to use, and offers insight into the number, duration, size and format of files on an account basis.
As we were unfamiliar with many Unix commands, we relied heavily on the documentation for installation and configuration. Once we were in the Web interface, the user manual became unnecessary.
Conclusion
Starbak deserves credit for developing an ingenious solution for Webcasting or recording a videoconference. This is the only all-in-one device specifically dedicated to the convergence of these two rich media forms of communication. With improvements to the viewing experience, greater Web-interface stability and the ability for a network administrator to adjust bandwidth, this platform will significantly lower the barrier for those who have videoconferencing systems and want to record a streaming media session or archive conferences.
For more information on Starbak and its products, visit www.starbak.com.
Perey is president of Perey Research & Consulting, a market research and business development consulting company. She can be reached at [email protected].
