让我们一起努力

So you’ve just arrived in San Francisco and picked up your rental car; you’re headed for a meeting somewhere in Silicon Valley. You get on the 101 heading south when it happens: You receive a "tech support" call from your father, asking about a problem he’s having printing or sending pictures of your children to your sister. 所以你在这里, 避开交通, trying to decide whether to take the Lawrence Expressway or El Camino Real, while at the same time asking your dad to give you details about what the onscreen error message 说s. 这足以让你心烦意乱.

This article won’t help you with intrafamily relationships, nor will it offer options on how to drive and use your computer at the same time, but it will provide an overview of a set of tools equally as helpful for training, 故障排除, 销售, 家庭电脑问题. Straddling the intersection of several technologies (including instant messaging, 流媒体, 视频会议, 应用程序共享, 和演示软件), collaborative computing tools are an emerging—and essential—part of your computing toolbox.

The tools are split into several key areas: 1) desktop presentation tools, 2)桌面应用工具, 3)群件, 4)增强的视频协作工具, 包括富媒体记录. The second part of this article will cover these areas, 但是在上半场, 让我们来看看这一切是从哪里开始的.

让我们从头开始……
Back in the early 1990s, 视频会议 systems were used for basic talking head meetings. 会议可能由几个实体会议室组成, each run by an operator and filled with participants; participants in each room saw themselves in one monitor (the "vanity monitor" as those of us who operated the rooms called it) and saw participants in another room in a second monitor. The rooms were connected by something called a multipoint control unit (MCU) that allowed the operators in any room to switch the video from room to room (that second screen) depending on who was talking. Some 单片机 even used a technology that allowed the video to be switched automatically based on the current predominant speaker—someone who, 说, 发言至少5秒.

这些系统对说话的人来说是足够的, but the way the 信息 was presented was substandard, often consisting of a camera focused on one part of the table where participants sat. 后来的系统增加了文档摄像机, 有顶灯的小型独立单元, 灯箱广告, 或者两者的结合. Papers would be placed underneath the document camera and displayed intermittently, 提供纸张或醋酸盐的巨幅图像, with a hand reaching into the image occasionally to scratch notes on the paper if other participants requested changes to the document.

This issue is not that far removed from basic video production for 流媒体 in a corporate environment. 的电视录像制作人, 谁经常只用一台相机拍摄, has to move back and forth between the presenter and the screen or projected image. 就像富媒体录像机一样, 例如那些从accorent或Sonic Foundry, which record the video of the presenter and a separate copy of the presentation, 视频会议 systems needed to find a way to present PowerPoint and other computer graphics tools that were then emerging.

最大的问题, 虽然, 是带宽, as most 视频会议 systems used T1 or lower data rates, and most video codecs required at least 768Kbps to provide adequate face quality for talking heads. Add to this the fact that the MCU was integrated into some lower-cost 视频会议 systems—the ones made by Polycom that would later become popular with enterprise customers—and the bandwidth issue was greatly exacerbated since video from all locations in a videoconference (the "points" or "nodes") needed to flow into a single point, 然后切换视频并发送回来. This meant a facility with a T1 that needed to do a four-point call would only be able to use 384Kbps for each node on the call.

许多技术创新都是如此, a small company invents a solution and then licenses it to the big players, each branding it with its own special name and supplementary tools. 在协同计算领域, 一个名为DataBeam的公司提出了一个解决方案, 后来被莲花收购了吗, then wrapped into IBM’s SameTime when Lotus was subsequently acquired. DataBeam’s proposed solution for the 视频会议 data presentation problem took root, 发展成为一种标准, 并成为了, 可以说, the foundation of all collaborative computing systems on the market today, 尽管有很多派生.

产品FarSite和技术T.120, allowed low-bandwidth presentation of graphic images at very low frame rates—sometimes as low as one frame every 2 seconds—to be sent on a separate channel from the main 视频会议 system. 低带宽场景, 通常小于128Kbps, was necessary since bandwidth would need to be stolen from various areas of the traditional videoconference.

到1996年，DataBeam的T.120-based technology had been licensed by more than 40 software and hardware manufacturers and service providers. 苹果等公司, 英国电信公司, 思科系统公司, MCI, 微软, PictureTel, and Sun Microsystems were using DataBeam’s toolkits to add real-time collaborative capabilities to products as varied as multimedia microprocessors, 桌面操作系统, 单片机, 以及视频会议应用. FarSite还包括文档协作, based on a product it released in 1993 that allowed for a radical new tool: the shared whiteboard.