Supercast is a SHOUTcast-compatible streaming MP3 audio server. Its most distinguishing feature is its ability to re-encode the source stream at one or more other bit rates and broadcast the resulting stream(s) along with the original. This makes it easier to simultaneously broadcast high-bandwidth and low-bandwidth streams with the same content. Another benefit over SHOUTcast is that Supercast is compatible with Windows Media Player.
Supercast will probably run on any recent Unix-like operating system; it has been tested under Linux (Debian 2.2 and Red Hat 6.1) and FreeBSD 4.4. Windows is not yet supported. It is written in the Python programming language (http://www.python.org/) and also requires the Twisted Python networking library (http://www.twistedmatrix.com/), version 0.12.3. Unpack the Twisted-0.12.3.tar.gz file in either the Supercast root directory or the directory above it, whichever you prefer. Alternatively, you can install the Twisted library system-wide using the included setup script. You must also have the LAME MP3 encoder (http://www.mp3dev.org/mp3/) to take advantage of Supercast's re-encoding feature.
Once you have satisfied the prerequisites, you need to configure Supercast. It's simple to configure Supercast as a single server with no re-encoding (like SHOUTcast), a pair of servers (one broadcasting the original stream and one broadcasting a stream that has been re-encoded for modem users), or even a group of three servers (where the third one broadcasts a re-encoded stream at a medium bit rate). In any of these cases, simply copy supercast.conf.dist to supercast.conf (or an alternative configuration file) and make the appropriate changes. THe available parameters are as follows:
mainPort: This is the port to which listeners connect to hear the broadband stream.
mainMaxListeners: This is the maximum number of listeners that can be connected to the main server; it is 32 by default.
sourcePort: This is the port to which all broadcasters connect. It defaults to mainPort + 1, and this is the best setting, because the port number that SHOUTcast plug-in users will enter is actually one less than the port to which the SHOUTcast plug-in connects.
sourcePassword: This is the password which broadcasters use to connect to the server. Change it.
titleFile: If specified, this is the name of a file to which the title of the source stream is written when a broadcaster connects to the server and to which "Off the Air" is written when the stream is done. This feature can be used to display the current stream title on a dynamically-generated Web page. No title file is written by default.
modemPort: If this port is specified, then the source stream will be re-encoded at 24 Kbps in mono at a sample rate of 22 kHz, and listeners can connect to this port to hear it. No one can broadcast directly to this server. If this parameter is omitted, then no low-bandwidth stream is produced.
modemMaxListeners: This is the maximum number of listeners that can be connected to the modem server, if any; it is 32 by default.
mediumPort: If this port is specified, then the source stream will be re-encoded at a certain bit rate (see mediumBitRate below) in stereo at a sample rate of 22 kHz, and listeners can connect to this port to hear it. As with the server on modemPort, no one can broadcast directly to this server. If this parameter is omitted, then no medium-bandwidth stream is produced.
mediumBitRate: This is the bit rate (given as a number in kilobits) at which the medium-bandwidth stream should be encoded. The default is 64 Kbps.
mediumMaxListeners: This is the maximum number of listeners that can be connected to the medium-bandwidth server, if any; it is 32 by default.
adminPort: If specified, this is the port to which server administrators and developers connect (using a Telnet client).
adminPassword: This is the password for the Telnet interface described above. Change it!
pidFile: This parameter specifies the name of the file to which Supercast will write its process ID (PID) when it starts. By default it is "supercast.pid".
interface: This is the IP address on which Supercast should listen for incoming connections. It must be written in quotes. If this parameter is not provided, then Supercast will listen on all IP addresses that belong to this system.
Supercast can also rebroadcast one or both of the streams to another SHOUTcast-compatible server. This is useful if you want to take advantage of Supercast's dual-bandwidth streaming but don't have enough bandwidth on your server to support many listeners; you can use a service such as Live365.com or StreamGuys.com to serve your listeners.
For this purpose there are three optional configuration parameters, mainRelay, modemRelay, and mediumRelay, each of which has three comma-delimited parts in its value: the relay server's host name or IP address (in quotes), the relay port (NOT in quotes; this is the actual broadcasting port which is the listeners' port plus one), and the password for the relay server (in quotes).
SHOUTcast-compatible servers can often be configured to run in relay mode, in which the server relaying the stream connects to the originating server as a listener. The disadvantaeg of this approach is that when there is no active stream, the relay server must repeatedly try to connect to the originating server. If it tries too often, it wastes system resources and bandwidth, but if it doesn't try often enough, it doesn't pick up the beginning of the stream. Therefore, whenever possible, don't run the relay server in relay mode and use Supercast's relay feature instead.
If you want to use Supercast for a purpose other than those documented here, then you'll need to modify the start script. For example, you can run multiple, separate servers in the same Supercast process. I'm doing it now and will try to make this arrangement more convenient to set up in the future.
Once you have configured Supercast, you can start it by changing to the Supercast root directory and running the start script. The server should then be ready for broadcasting. The easiest way to shut down the server is to run the stop script in the Supercast directory. If you want to use a configuration file other than supercast.conf, then include its name on the command line when running the start and stop scripts.
Supercast implements basic statistics about the listening time and bandwidth consumption for each server. You can view this information in a Web browser. For example, if the broadband server is on port 8000 of the local machine, you can view the statistics by going to this URL:
http://localhost:8000/index.html
Note that in either of the multiple-bandwidth configurations, the statistics for the broadband, medium-bandwidth, and modem servers are completely separate. All statistics are lost when the server is shut down and are never reset while it's running; I hope to address these limitations in the future.
The Telnet interface to the server is very primitive. After logging in with username "admin" and the password specified in the configuration file, one enters lines of Python code to be run in the server process. Using the interface effectively requires familiarity with Python, the Twisted library, and the Supercast code, so it's probably only suitable for developers. Sometime I'll write a nice Web-based administration interface.
I developed Supercast specifically for ACB Radio (http://www.acbradio.org/), a group of Internet audios treams operated by the American Council of the Blind with help from many other blind and visually-impaired people. Supercast is in production use now on ACB Radio Interactive (http://interactive.acbradio.org/). Thanks to the rest of the ACB Radio Interactive team for helping me test the server throughout its development, and even for helping me name the software. Be sure to listen to ACB Radio Interactive for live, unpredictable Internet radio by the blind, for the world!
Supercast is certainly not finished yet; I've mentioned already a few improvements which I hope to make sometime soon. It also needs to be able to list the streams that it broadcasts on directories such as yp.shoutcast.com and yp.live365.com. An integrated facility for automatically broadcasting pre-recorded material may also be helpful.