Mediastreamer is a portable C library that allows you to create and run audio and video streams. It is designed for any kind of voice over IP applications. It features RTP connectivity, audio codecs (Speex, iLBC, G711, GSM, and AMR), video codecs (MPEG4, H263, H264, and Theora), sound card I/O, wav file streaming, webcam video capture, echo-cancellation, conferencing, parametric equalization, and various other utilities. It has a modular design that makes it extensible through plugins. This is the media-streaming component of linphone, a GPL SIP video phone.
swampex (or Swamp Explorer) is a cross-platform library designed to work with raster maps in Ozi Explorer format. Using this library, you'll be able to collect maps in the file system, get information about map calibration, find maps by latitude/longitude, render maps in SDL surfaces, and more.
The dywapitchtrack library computes the pitch of an audio stream in realtime. The pitch is the main frequency of the waveform (the "note" being played or sung). It is expressed as a float in Hz. dywapitchtrack is based on a custom-tailored algorithm which is of very high quality, very accurate (precision < 0.05 semitones), with very low latency (< 23 ms) and very low error rates. It has been thoroughly tested on the human voice.