Presentation Name Slide 1 Broadcasting the Open Source Way An overview of how KW Goth-Industrial Radio will implement a full-time Internet radio stream using entirely F/LOSS software R. Brent Clements

Presentation Name Slide 2 Overview Audio Studio Digital Audio Workstation Ardour DAW software Rivendell: Automated radio Streaming Solutions Icecast/Shoutcast Peercast Media players for listeners Jack Audio Connection Kit Overview Principals Setup and Usage Plugins

Presentation Name Slide 3 Audio Production Studio Audio Gear Microphone Decent Microphone (optional) Mixing Console (optional) Instruments/DJ gear/etc (optional) Sound-Proof Room (optional) Digital Audio Workstation

Presentation Name Slide 4 Digital Audio Workstation: Heart of the studio Digital Audio Workstation Hardware Considerations Audio Device Professional Cards (RHE Hammerfall, M-Audio) Commercial grade cards (SB Live/Audigy, others) Video Device card should not hog PCI bus System Specs ideally at least 1 Ghz with 512MB RAM Fast Hard Drives—Configured efficiently

Presentation Name Slide 5 Digital Audio Workstation GNU/Linux Specialized Distributions dyne:Bolic Others Configured for low latency often takes liberties with root permissions to bypass cycle consuming security tasks Configuring a common distribution Kernel Configuration realtime-lsm

Presentation Name Slide 6 Ardour: Pro Quality DAW software—GPL'ed Produced/released by Linux Audio Systems under GPL 24 simultaneous 24-bit channel recording at any sample ratefrom 8kHz to 192kHz Any audio from the audio card can be recorded with one sample accuracy along with output from any other audio application

Presentation Name Slide 7 Rivendell: the DJ in a tarball Radio Station Automation All music, commercials, wittless DJ banter and station ID's pre-recorded and sequenced for unattended playback DJ and/or Music Director can work from a studio or their own workstation to determine what is played over the air Produced by Salem Radio Labs for use by their chain of religious radio stations Honours the GPL, and a user community is starting to form to support it Alternatives Soma Suite XMMS DJ 24 hours a day

Presentation Name Slide 8 Getting your message out there Streaming Digital audio provided in realtime to the enduser Listener can pick up at any time in the stream Some text information (song title, copyright info, “station ID”) can be embedded in the stream DMCA Formats Ogg Vorbis MP3 even more proprietary Commercial services Live365.com Doing it yourself Using Shoutcast Peer-distributed streaming

Presentation Name Slide 9 The cost of streaming Bandwidth requirements 8kbps – 128kbps 56kbps – 96kbps Stereo most common 3 to 5 simultaneous listeners possible served by residential DSL or Cable Multicasting The best sollution Not supported by the bulk of the Internet Available for Intranet broadcast Mbone: Limitted subset of the Internet connected by Multicast- enabled routers

Presentation Name Slide 10 Icecast=Shoutcast protocols + GPL Icecast is a F/LOSS implementation of the Shoutcast Protocol Any media player capable of listening to a Shoutcast stream will work with these streams Shoutcast YP directory listings are created automatically

Presentation Name Slide 11 Peercast: Share the load Any listener of the stream acts as an alternate “server” for other listeners to connect to Clients will be redirected down the chain until a point that is not serving its limit is found Each user of peercast can control other's access to the stream Also allows a user-selectable number of non-peercast direct connections at each node Available as standalone app or plugin for winamp right now

Presentation Name Slide 12 The listener end Streaming Media Players Shoutcast YP/Stream Directory listngs Specific Platforms Support for GNU/Linux, Windows, MacOS Portable Devices Wi-Fi hotspots Peercast is compatable with any player that supports Shoutcast streams

Presentation Name Slide 13 Part Two Jack Audio Connection Kit The glue that binds......

Presentation Name Slide 14 The Problems One program that can do all audio capture, processing, and output is generally an expensive commercial app Connecting sepparate programs together is not practical for realtime audio processing where no syncronization is provided Standard API and framework is necessary to facilitate universal compatability among numerous projects by unconnected developers

Presentation Name Slide 15 The solution: jackit JACK is a low-latency audio server Callback system where jack applications register functions to be called when it is time to process the next “frame” of audio data Callback system is syncronized with the clock of the audio output device at the end of the chain Mechanism for connecting an output stream from one Jack app to the input of another in a user-defined order Graphical tools make it easier to connect to apps together

Presentation Name Slide 16 The principal of operation

Presentation Name Slide 17 Realtime processing OS must guarantee a maximum response time to interrupts from software or the system hardware Necessary to ensure that audio “artifacts” are not created by a lapse in the data flow Only root can assign realtime privileges realtime-lsm a kernel module that will grant RT to userspace processes

Presentation Name Slide 18 Configuration made easy: qjackctl Simple interface that works like a cable patchbay Connect outputs of one program or driver to inputs of another Alsa drivers create input ports for line/mic in and output ports for output channels Each program appears in the patchbay to be connected as appropriate Multiple instances of programs appear sepparately in the patch bay with unique port names

Presentation Name Slide 19 Working example Insert neat live demo here.....

Presentation Name Slide 20 Available plugins common player output plugins XMMS mplayer Synthesizers Visualizers Filters and audio processing filters

Presentation Name Slide 21 Conclusions Guerilla Radio on the Internet Professional quality studio recording possible with F/LOSS tools End-to-End solution for Internet Broadcasting without proprietary software Arbitrary audio handling possible using jackit Questions?