The PKSampler is a live DJ tool. It is different from other "live DJ tools" in that it focuses on allowing the user to mix many samples at once. The focus is on a simple touchscreen interface that allows quick access to user-supplied loops and samples. The user interface is driven by Python and Qt, and uses 3d POV-ray images for widget animations.
The SIP Switch is a Web application which allows you to use multiple SIP accounts on the same phone. This lets you use the call plans of different VoIP companies (using SIP) with one IP phone device. It does the third party SIP registration so you can receive all your calls on the sipswitch account. On dial out, you can set prefixes to make your outgoing calls with such or such provider.
MrsWatson is a commandline audio plugin host. It takes one or more plugins, sends an audio signal to them for processing, and saves the resulting output. Although the plugins think they are running in realtime, processing is actually done offline (this is not the same as the "offline" processing in VST terminology). This makes MrsWatson ideal for developing or debugging plugins, or processing audio on a server.
Sfront compiles MPEG 4 Structured Audio (MP4-SA) programs into efficient C programs that generate audio when executed. MP4-SA is a standard for normative algorithmic sound, which combines an audio signal processing language (SAOL) with score languages (MIDI and SASL). Under Mac OS X and Linux, sfront supports real-time, low-latency audio input/output and MIDI input. Under Mac OS X, sfront supports the creation of AudioUnit plug-ins. The documentation includes a book about SAOL programming.
Mup produces very high quality PostScript printed music or a MIDI file from a text input file. It can handle almost any kind of music, instrumental or vocal, including tablature, shaped notes, guitar grids, alternate tunings, user-defined symbols, and much more. Mup has been under active development since 1992.
Speex is a patent-free compression format designed especially for speech. It is specialized for voice communications at low bit-rates in the 2-45 kbps range. Possible applications include Voice over IP (VoIP), Internet audio streaming, audio books, and archiving of speech data (e.g. voice mail).