Bamba--Audio and video streaming over the Internet

IBM Journal of Research and Development, Mar 1998 by Willebeek-LeMair, M H, Kumar, K G, Snible, E C

Bamba is a streaming system that was designed to run over existing computer network infrastructures. In particular, it is versatile in dealing with the heterogeneous nature of this environment and the unpredictable congestion behavior of today's network traffic. In the Bamba system, audio and video are compressed into a Bamba file. This file is specially formatted to interleave the audio and video content and may even be extended to include other data types. The Bamba file is placed on a server. A client equipped with the appropriate Bamba software is able to communicate with the server and receive the Bamba audio/video file. If the network conditions are suitable (sufficient sustained bandwidth is available), this file, streaming across the network, is played at the client immediately. Otherwise, the file is played once uninterrupted playback can be ensured.

The Bamba streaming system has several key features. The first of these is the quality of the audio and video, where the audio is set at a constant 6.3 Kb/s and the video ranges from very low bit rates of tens of kilobits per second to hundreds of kilobits per second. The second is the fact that both the audio and video compression are based on standard algorithms and can be performed by standards-compliant decoders. Third, the Bamba streaming system uses either a standard HTTP server or an enhanced video server running RTP over UDP/IP. In the HTTP case, no special server software is required to store and send Bamba clips, and the transmitted streams can traverse firewalls with no special firewall configuration requirements. In the case of the video server running RTP over UDP/IP, additional functionality is provided by means of a control protocol between the client and server. This functionality includes pacing of the transmission stream at a target bit rate as well as specific start and end times of transmission within an audio or video file. Finally, the Bamba player has been implemented either as a helper application, which runs outside a Web browser, or as a browser plug-in, which enables application developers to embed audio and video clips easily within an HTML document or as a Java** applet, which can be downloaded directly from a Web server containing Bamba clips without requiring special software installation at the client.

The rest of this paper is organized as follows. In Section 2, we describe the underlying Bamba technology. This includes a description of the video-compression algorithm as well as details related to the overall system design. In Section 3, we describe several enhancements made to the basic Bamba streaming system, such as increased robustness in lossy-network environments. A description of the Live Bamba architecture is given in Section 4. The paper is summarized in Section 5.

2. Bamba technology A base requirement of the Bamba streaming system is to function within the WWW standard HTTP-based client-server architecture. In this section, we provide a description of the overall client-server architecture and present details concerning the compression algorithms. We also describe the Bamba file format and synchronization technique.