Wireless Live Video Streaming from Desktop Computers Using Sorenson Broadcaster

Document Type

Presentation

Publication Date

6-2000

Abstract

A key component of neuroscience education is the use of patients to demonstrate neurologic disease. Patient demonstration provides opportunity to teach physical examination technique, and to observe movement abnormalities associated with nervous system disorders. In a vertically integrated neuroscience curriculum, clinical principles are introduced in introductory level courses, resulting in a greater demand for patient use in the “preclinical” classroom environment. With increased patient involvement, however, comes increased problems with patient accessibility. A solution to the problem of accessibility is to be able to show patients live, in the clinic, to a classroom of medical students. Remote broadcasting of live video promises to give clinicians this capability. Use of wireless remote broadcasting enables even more flexible scenarios such as the participation of an entire classroom in the patient rounds experience. We will demonstrate several hardware and software configurations currently available.

In the present project we will demonstrate the creation and delivery of live video streams using two different capture and delivery configurations. The first will involve video input through an ixTV PCI card in a 400MHz Macintosh G3 desktop computer. This computer will broadcast through a direct ethernet connection to "online" playback machines. The second configuration will demonstrate video input through a PC capture card (Irez, CapSure) to a Macintosh G3 PowerBook. This computer will broadcast live video streams through a wireless LAN card to a base station port for ethernet distribution. Consequently, this set-up will enable wireless remote transmission of the video stream from any location within the demo area.

Several broadcast scenarios within Sorenson Broadcaster (1.0) will be demonstrated: Unicasting to a single recipient; Multicasting without a replication server; and Broadcasting using a replication server. Unicast streams go to individual IP addresses and are consistently transmitted through Internet routers and firewalls. Multicast video streams go to multiple registered recipients within a local area network. This protocol optimizes bandwidth consumption within that network. Broadcasting using a replication server involves sending a unicast stream to a replication server (located at Wright State University) which will then replicate the incoming stream as many unicast streams that may be successfully transmitted through routers and firewalls on the Internet.

Remote broadcasting of live video will allow clinicians to present a greater variety of teaching cases to students in traditional classroom settings. It will also allow interaction between students, physicians, and patients during the learning experience. The live presentations may also be recorded for individual student review at a later time. These features make live video streaming the ideal complement to the use of in-class patient demonstrations and archived streaming video in the vertically integrated Medical Neuroscience curriculum.

Our original idea was to allow people to see the wireless roadcast of live video streams in action. We are planning to do this by having a remote crew (eg. Gary Nieder and Mark Anderson), with video camera and broadcast computer, roving around the demo area broadcasting to a playback machine located at our assigned station in the demo area. With this set up, interested attendees would have opportunity to examine, first hand, both ends of the broadcast process. They would be able to evaluate the quality of the streams, and get an appreciation for the physical limitations of the hardware involved, especially the airport card and base station. We could demonstrate several of the broadcast scenarios of which Sorenson Broadcaster is capable.

We selected to do a demonstration because: (1) In a platform talk there would be very little time available to actually demonstrate the live broadcast. And that broadcast would probably show only one of the variety of scenarios available through Sorenson Broadcaster. For example we would not have time, during the presentation, to establish a 'reflected broadcast' using our OS X server at WSU. (Plus, there would be little time to achieve optimal streaming quality by adjusting broadcast parameters to match the internet transmission speed at that moment). (2) With a platform presentation, the audience would not be able to develop an appreciation for the relationship between the remote broadcast unit (i.e., video camera, portable computer with aircard) and the base station hook up. (These would likely be remotely located outside of the presentation room). This 'hands-on' experience is the best way to evaluate the quality of the video streams and see the other physical limitations of both hardware and software.

Comments

Presented at the 13th Slice of Life Workshop, Salt Lake City, UT.

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