CGIcast

WTF is CGICAST?

cgicast is a selection of perl scripts which are intended to make it possible to perform live internet radio via any standard (read cheap) web hosting account which provides CGI facilities. Typically these accounts are about $5 a month compared with $15/month which you would pay to someone like live365.com to host your streams (and they still add advertising to your stream!).

Is This Legal?

I'm sure some hosts will not like it.... maybe you wanna check with them first, furthermore, the RIAA and other music industry bodies may take offence at streaming music. This code covers none of this legal stuff, just promise to be good people and don't accept payola.

How Does It Work?

There are 3 scripts - the client runs on your local machine and sends the mp3 data in chunks up to the receiver script running on the web host, this script stores the most recent audio on the filesystem. When the listener connects they connect to the transmitter script - this serves the mp3 data from these files in almost real time.

Files? Perl? Haven't you heard of sockets and shared memory?

This is a hack, but I targeted it at the lowest common denominator, I don't use any special modules of software on the server side - just whatever will probably be available. On the Client side there are a few more bells and whistles - but not many.

Bells an What?

Oh to make it work best you need to have some common unix tools - in particular SoX and "esdmon" are used for getting raw audio data. LAME is used for encoding audio to mp3, and cURL is used for pushing the data to the server (I could've done this in pure perl, but it saves about 15 lines of code). You can also encode using OGG/Vorbis if you're wanting to get the best quality with the least amount of licensing problems. Oh and one example demonstrates relaying an audio stream from an SoX

LAME or OggEnc

cURL LAME is the only one that's not commonly found in unixs distributions, because of the legal problems surrounding the mp3 patents.

Download CGIcast and untar the distribution somewhere safe, don't untar it straight into a cgi directory on a web server, there are probably secirity problems with the client if you let just anyone run it. Take the 3 perl scripts and first setup the remote system

Go To your web account and put cgicast_receiver.pl amd cgicast_transmit.pl into your cgi-bin directory on your website.
Make both of these executable and check that the first line matches the location of perl on the web server.
Create a directory which is writeable for the cgi-processes - note that this may vary depending on the web server setup. I use cgicast as default.
Edit cgicast_reciever.pl, set $password to something more secure. Set the $file_dir parameter to point to your chosen directory.
Edit cgicast_transmit.pl, set $file_dir to point to your chosen directory.
Now, On the client side, edit cgicast_client.pl, set $remote_server to the name of the web hosting machine, set $remote_path to the path pointing to the cgicast_receiver.pl script. Set port appropriately (almost always port 80). and set your password to the same as on the server.
You can also adjust your source by modifying the open MPEG command, there are several exaples using standard command lines. Remember if you change the bitrate to change the relevant timing parameters. The default configuration should be fine for testing with live audio.
Now you're all setup - adjust your mixer and start cgicast_client.pl to start sending the audio to the server. Now people can listen almost live (the default setup produces 30-60 seconds latency) by pointing their player to the cgicast_transmit.pl script.

Wow That Rocks! No Seriously I'm Not Being Sarcastic!

Of course you're not.

How Can I Ever Repay You?

Just send thanks, adulations, and dj gigs to me ;-)