HsVoipSDK is an audio streaming / voice over IP SDK in C / C++. HsVoipSDK is shipped with full C source code and includes the following components: HsSound C source library: Audio library for Windows HsRtp C source library: RTP protocol library HsSock C source library: Socket interface library audio.c: Audio streaming / Voice over IP application for Windows (uses the above components) HsVoipSDK is designed for use from C/C++ applications on Windows platforms. The use of HsVoipSDK is royalty free. HsVoipSDK source code can be used to develop Voice over IP audio streaming or voice chat applications in C / C++. Features of Audio Library (HsSound): Detection of installed audio devices Recording audio buffers from audio input devices Playback of audio buffers to audio output devices Single and dual frequency tone buffer synthethis / generation in software Operations on WAVE files (reading writing audio to/from WAVE files) Supported audio formats: Linear PCM, GSM 6.10, G.711 a-law and u-law Recording to wave file Recording to memory buffers Playback from wave file Playback from memory buffers Simultaneous playback and recording Anti-jitter buffering Configurable sampling rate and audio format / codec RTP Library (HsRtp): HsRtp library implements RTP protocol (Real Time Transport Protocol) according to RFC 3550 and RFC 4571 HsRtp supports operation over UDP or over TCP as described in RFC 4571. HsRtp performs protocol encapsulation and de-capsulation, packet building and parsing functions HsRtp by itself does not provide transmission or reception functions. In HsVoipSDK, the transmission and reception is done with HsSock library Socket Interface Library (HsSock) HsSock is a C source code library for interfacing to Windows and Unix network sockets layer. HS Sockets hides the complexity of low level socket api from user application.