Streamworks Player 2.02
Streamworks Player 2.02
Streamworks Server 2.O
Xing Technologies, (along with VDOnet) is a pioneering firm in the field of multimedia streaming over the Internet. Web sites have used the firm's StreamWorks tool to transmit audio and video content to Internet users since the inception of streaming (in the middle of 1995). With a fast connection and StreamWorks Player2.02 installed on the system, it is possible to view films within a few seconds from the selection of a StreamWorks link on a Web page. As with VDOLive and Vosaic, Xing's StreamWorks is an exclusive server-reproducer solution. It uses MPEG video files, but the player only works with films issued from the StreamWorks server.
StreamWorks Player 2.02 is installed as an application helper (and not as a plug-in) and it is launched when a StreamWorks film is selected on a Web sight. But seeing as the client and the server communicate on the UDP band, it is also possible to connect directly to a StreamWorks server from the reproducer without using a browser. An interesting function of the player is that it remembers the Url of each visualized file. If you wish to see a particular film again, you merely have to select it from the Player's menu. It is not possible to save the files transmitted via StreamWorks on disk, but the program allows you to enlarge the viewing window full screen.
It is possible to turn the audio on and off, but not to regulate the volume or change the playing speed. StreamWorks allows the operator to coninue surfing on the Net or open another application during the reproduction of a file. The user hears the audio without interruption while downloading the film, but the StreamWorks Player disappears when passing to other applications - hiding the video image behind the other application's screen. VDOLive handles the problem better, keeping the video in the foreground regardless of the application in use. The quality of the majority of films that we viewed on our network connection was quite good.
The video-audio synch was good and the smoothness of the moving images was acceptable. On a 28.8 Kbps modem connection however, the overall viewing quality was poor. StreamWorks servers adapt the rate of transmission to the speed of the connection, but if the program notices that the connection is inferior in speed to the chosen film's minimum requirement, it crudely responds with an error message and makes no attempt to visualize the film. The StreamWorks Server requires a connection speed of 33.6 Kbps or higher to reproduce the audio and video components of a film. With a 28.8 Kbps modem connection, the server merely renders an audio streaming, ignoring the video portion. StreamWorks doesn't measure the speed of connection on its own, but relies on the operator who must select it from a menu list. This has allowed us to trick the StreamWorks player into rendering both audio and video over a normal telephone connection (by selecting a connection speed higher than the actual 28.8 in use). After a two or three second delay, the opening frames appeared, but in the process large portions of audio and video signals were subsequently ignored.
Web administrators using StreamWorks can maintain a certain control over the quality of video reproduction through a text file PLY (play), that specifies the way in which the server will transfer the video file. The information contained in the .PLY file includes the speed of data transfer to be used for any particular type of connection. Usually in the configuration for a slow connection a .PLY file is created for rendering only the audio or only the video. Xing sells the server software according to the total bandwidth that it will handle, starting from a low end speed of 128 Kbps.
The server subdivides the available bandwidth according to the speed of connection of each consumer, up to the maximum acquired amount. If configured correctly, StreamWorks facilitates Web administrators in the distribution of standard MPEG-l format files, maintaining relatively high quality for the majority of users, so long as they limit themselves to slow connections of only audio or video. The .PLY file allows the user to specify that only a particular segment of a film be reproduced at a certain bandwidth.
This means that it is possible show an abbreviated version of a film to telephone-connected users who might not otherwise have the patience of wait for the completion of the file. We tested the latest version of StreamWorks 2.0 Server for Windows NT and, apart from the slow viewing via a telephone connection; the only problem encountered was in the acquisition of the test files: StreamWorks only reproduces MPEG-l films and not the more common MPEG-2 files. StreamWorks sells a "transmitter" hardware package that handles live audio and video emissions and encodes the live audio in the MPEG-l format required by the StreamWorks Server (Xing also sells MPEG Encoder, a utility that converts the files into the MPEG-l format).
In essence, the transmitter is a desktop computer dedicated to the codification of the incoming multimedia signal and to its relative transmission to the system where the StreamWorks Server is installed (generally the same system used as the HTTP server). StreamWorks will be interesting for those Web administrators who wish to keep tabs on the way the videos are presented at the various speeds of connection. The capacity to reproduce only audio signals at certain bandwidths makes StreamWorks a viable solution for those Web sites that prefer to maintain the integrity of their videos than to run the risk of giving a bad impression to patrons connected via telephone lines.
Last updated 7-Jan-97
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