Multimedia Broadcasting over the Internet: Part I

is coming of age. In addition to reprocessed audio or video that's transferred from radio or TV to the Internet, webcasting now also means broadcasting new, original content—sometimes live— on the Web. Taking advantage of streaming audio and video technology, site producers can bring real-time sound and vision to the Web. With the present technology, audio and video must be compressed almost to the breaking point to squeeze it through a 28.8-Kbps modem line, which means plenty of people will find it's not worth waiting for. However, this problem hasn't stopped millions of people from downloading viewers and seeking out webcasts. Listening to music or watching video straight off the Internet (Web) still creates a strong enough buzz that people overlook shortcomings like crackly audio, slow download times, and grainy pictures. Consequently, a number of Internet radio stations offer commercially appealing programs to an international audience. The Internet protocols that transmit this data require individual connections between servers (or senders) and their clients (receivers). The proliferation of such connections proves quite expensive , because they consume very high network bandwidth and processing power at the server. Internet radio stations employ networks of increasingly expensive servers. Although the industry is still in the early stages of webcasting, we can already foresee what the Internet will offer a few years down the line: clear, crisp audio and full-screen, high-quality, on-demand video. We've developed a technology that provides all these required features for Inter-net webcasting. This technology consists of „ IP Simulcast, a new Internet broadcast protocol , which provides inexpensive, efficient, and reliable audio and video broadcasting. „ New audio and video compression algorithms, which allow real-time audio and video transmission of data at low bit rates and with high quality. In this article, we describe a new Internet broadcast technology. In Part II (next issue), we'll present a video compression algorithm for ultra-low bandwidth applications. Three fundamental methods exist for transmitting data on the Internet: IP Unicast, IP Broadcast , and IP Multicast. IP Unicast transmits data (or a packet) from a sender to a single receiver. IP Broadcast sends data from a sender to an entire subnetwork. IP Multi-cast enables the delivery of data from a sender to a set of receivers that have been configured as members of a multicast group in various scattered sub-networks. Radio and television broadcast applications require a one-to-many data distribution model in which data …