HsVoipSDK

This is a streaming VoIP SDK for the Windows API.

Written in C/C++ this SDK will help build streaming audio in VoIP functionality into your applications for the Windows API. The product includes full C source code and comes with the following components RTP protocol library, Audio library for Windows, socket interface library and Audio streaming / Voice over IP application for Windows that uses these components. Code distributed as part of the applications developed does not attract any royalty. Functionality provided by the tool kit includes detection of installed audio devices, recording audio buffers from audio input devices, playback of audio buffers to audio output devices, operations on WAVE files (reading writing audio to/from WAVE files), single and dual frequency tone buffer synthesis / generation in software, etc. The SDK will help you provide support to audio formats like linear PCM, GSM 6.10, G.711 a-law and u-law.

Other functionality that could be made available include recording and playback to/from memory buffers, playback from WAV files, simultaneous playback and recording, anti-jitter buffering, configurable sampling rate and audio format/codec. RTP library provides the protocol support. Operation over UDP or over TCP as described in RFC 4571 is supported. Protocol encapsulation and de-encapsulation features are provided. Packet building and parsing functions are supported. Transmission and reception is done with HsSock library. This library is a C source code library for interfacing to Windows and Unix network sockets layer. TCP server and client applications, UDP applications and mixed TCP server, client and UDP applications are supported through the library. This is a very good product. If you are looking for a similar solution, you should try it in your exact workflow.

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.