SIP/RTP and VOIP application developers now can use a new SDK from NetResults, called VoIP Development Kit (VDK):
VDK (http://www.voipdevkit.com) aims to ease and speed-up the development of any VoIP application by giving to programmers a clean, simple and yet powerful and complete API to our VoIP engine; programmers now can concentrate on the features and usability of their applications without worrying about the technical and more in-depth aspects of a VoIP-based application.
Being able to be run over the most common Operating Systems (Win32, Linux and MacOsX) it will ease the distribution of VoIP-based application to a vast number of users and to add VoIP capabilities to existing software.
The main interface is for the C++ programming language but there is an external module to use it with Visual Basic and Java Applets, and a Windows Mobile 6.x port is under way.
The Voip Development Kit (VDK) is a software framework to create Voice Over IP application in a very easy and rapid way; it aims to be employed by a wide variety of users in very different scenarios.
It was created so it could run on many different platforms: Windows, Linux (both 32 and 64 bit) and MacOs X versions are available (Windows Mobile 6.x port is being worked on); the main target programming language is C++ but there are modules to use it with Java and Visual Basic as well, other ports (python and php) are being considered.
Thanks to its VirtuaDev® technology every single media source on your PC is seen as a VDK Virtual Device:
i.e. microphones are input devices while speakers are output devices; audio files stored on your hard disk can be seen as input (play) or output (record) devices and, obviously, VoIP calls are both input and output devices at the same time.
Any of these devices can be connected with each other (i.e. any number of input device can be connected to any number of output devices) and the media stream will automagically flows from the former to the latter and mixed seamlessly without any user’s interaction but a single API call.
Technical features list:
# Dynamically loadable codecs (G711, AMR**, Speex, G726, G729**, iLBC and GSM already provided)
# Voice Activity Detection, Silence Suppression and Comfort Noise Generation
# DTMF reception and generation (In-band, RFC2833, SIP INFO)
# Adaptive dejitter buffer
# NAT friendly
# Multi-line conference
# Play and Record files in all the major audio formats
# Multiple I/O Device support
# Multiple audio framework support (DirectSound, WinMME, Alsa, OSS, CoreAudio)
# Connection-based volume settings
# Full support to multi-core architectures
** Need a separately purchased license
Download a free trial for your Operating System of choice right here and start to develop VoIP applications!
To create a applications that will have SDK include IVR (Interactive Voice Response) Systems, Conference Servers, Callback Systems, and other telephony applications then http://www.voipcore.com/ is a good option.