Network-based video distribution and a digital camcorder
For my continuing review of new technologies that create and distribute full-motion audio and video over IP networks, this month I tested RealNetworks' RealSystem G2 video distribution software and Sony's DCR-PC1 Digital Handycam camcorder. RealSystem G2 is a refined and full-featured fifth-generation network-based video distribution product with an extensible architecture. RealSystem G2 includes a wide array of features, including broad open-standard support, realtime updates for new codecs, and a new file format that supports multiple-client bandwidths from one file. Add these features to multiplatform support, and you have a video product well suited to today's heterogeneous-network enterprise computing.
On the other end of the video stream, Sony's DCR-PC1 Digital Handycam camcorder is a wonderful example of how far video-recording technology has come over the past several years. Normally, the Windows NT Magazine Lab doesn't review consumer products, but the DCR-PC1 is among the first of a new generation of digital camcorders that directly communicate with a computer. I took the DCR-PC1 on a recent vacation and became familiar with its strengths and weaknesses. Comparing this digital video camcorder to its analog counterparts is like comparing a motorcycle to a bicycle: Both will get you where you want to go, but the motorcycle gives you more options.
RealSystem G2
RealNetworks' RealSystem G2 is a software media delivery system comprising three components: RealServer, RealProducer Plus, and RealPlayer Plus. You can distribute the components across several systems or install them on the same system. You can download free clipped versions of RealServer G2 (with 25-stream support), RealPlayer G2, and RealProducer G2 from the RealNetworks Web site. These basic versions of the RealSystem G2 components contain fewer features than the Plus versions contain. I review the Plus versions here.
I installed RealSystem G2 without a hitch on the Lab's Intergraph TDZ-2000 and Compaq SP700. Both of these high-end workstations are dual-processor systems. The Intergraph has 333MHz Pentium II processors; the Compaq has 450MHz Pentium II Xeon processors. Although RealSystem G2 supports numerous platforms, including Macintosh and a variety of UNIX types, RealNetworks introduced the product to the market for NT. RealSystem G2 is compatible with NT security and authentication, has links to NT's Performance Monitor, and gives administrators the option of installing the software as an NT service.
The RealServer video server does not require NT Server to operate. I installed RealServer on an NT server and an NT workstation without difficulty. The RealServer installation asks you to identify numerous ports for communication. A few of the ports you need to identify are for the Real Time Streaming Protocol (RTSP) and HTTP, and one port is randomly assigned for Web-based administration. After you've defined the ports and decided whether to run RealServer as a service, the software installation is complete, and you don't have to reboot. Because the interface to the software is HTML-based, you can administer RealServer from anywhere by using a Java-compatible Web browser.
Screen 1, page 140, shows RealServer's Web-based RealAdministrator interface, viewed through Netscape. RealServer looks more like a Help file, or an elaborate Web page, than a software program. After you start drilling into the menus, however, you quickly discover there is more here than static Web pages. You use the left side of the screen as a reference listing of configurable options, and the remainder of the screen for applets that are related to the configuration of options you choose from the list.
The Welcome option introduces you to RealSystem G2's components. You can use the Sample option to test whether the software is functioning properly. Choosing the Monitor option displays RealSystem G2's Java Monitor, a full-featured activity monitor for one or more RealServers on a network. Java Monitor is fully customizable, with color-coded graphs that track CPU utilization, memory, bandwidth, and the number of clients that are connected at a given time. You can track user connections by IP address, type of connection, how long a connection has been operational, and the file a connection is currently accessing.
When you choose the Configure option, four categories display: General Setup, Broadcasting, Cache, and Security. The subcategories under General Setup let you configure ports, logging, IP binding order, MIME types, maximum client connections, and maximum bandwidth, and let you create, delete, and edit Mount Points. A Mount Point is a redirector or locator file that defines the location of your RealServer content. The Mount Point file's default path is \program files\real\realserver\content. You need to modify this path if you change your content's location.
RealServer's Cache category under the Configure option consolidates requests and broadcasts them to reduce bandwidth consumption. You can use the Cache option to restrict the amount of content RealServer caches. RealNetworks says that one RealSystem G2 server can handle roughly 1500 simultaneous unicast streams, a figure that is on par with similar products from other vendors. RealServer also supports multicasting, which consumes less network bandwidth than unicasting consumes. Another bandwidth saver is RealServer's splitting capability. Splitting is the process whereby one or more splitter RealServers connect to a primary or source RealServer and help the source server provide content to end users. Splitting can increase performance and decrease the amount of bandwidth the network consumes.
RealProducer Plus is RealSystem G2's content creation component. I installed RealProducer Plus on the Lab's Dell Precision 610 workstation with dual 400MHz Pentium II Xeon processors, a Winnov video capture board, and a Toshiba video camera. I also installed RealProducer Plus on a Toshiba Tecra 780CDM laptop with stock video camera and 266MHz Pentium II processor. I had no problems with the installation on either machine. As with RealServer, rebooting is not necessary to use RealProducer Plus after installation.
RealProducer Plus' main interface contains two small video screens. One screen displays video input; the other screen displays encoded output. RealProducer Plus has three wizards—Record from File, Record from Media Device, and Live Broadcast—that make preparing your content for public and private networks quick and easy. Each wizard walks you through a series of straightforward menus.
RealProducer Plus can convert .avi, .mov, .qt, .wav, .au, .mpg, and .mpeg files to a RealMedia (.rm) stream, which Screen 2 shows. The software also supports other file formats, including text, .jpg, VRML, MIDI, .aiff, .asfv1, .viv, and RealAudio (.ra). RealSystem G2 introduces SureStream, RealNetworks' new transport technology. SureStream uses single media files that dynamically scale bit rate according to available bandwidth, delivering content to users at all connection rates. RealSystem G2 also includes the option to create independent single-rate streams.
After you decide what type of file to create and what bit rate to optimize the file on, you need to select the best audio and video preferences for your content. RealProducer Plus' audio choices include Voice Only, Voice with Background Music, Music, and Stereo Music. RealProducer Plus' audio codecs produce stunning sound. I made several test clips at a variety of bit rates and audio settings, and the sound was the best I've encountered in streaming audio. What I heard was really music to my ears.
The video options in RealProducer Plus include Normal Motion Video, Smoothest Motion Video, Sharpest Image Video, and Slide Show. Because RealNetworks based RealSystem G2 on open standards, you can use many plug-ins and utilities from third-party vendors, including plug-ins for Microsoft's PowerPoint, to create multimedia presentations. Some third-party tools target Synchronized Multimedia Integration Language (SMIL), a proposed standard that the World Wide Web Consortium (W3C) supports. A complement to HTML, SMIL lets content creators choreograph multiple media types to create rich, professional presentations.
RealSystem G2 is a significant release that raises the bar for Web-based video distribution. The biggest improvements are to server communications and audio that tolerates packet loss. Expect the battle among vendors for the position of Web-based video distribution king of the hill to continue. You and I will emerge as the real winners.
Previous
Register
