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iVoIPEngine™ * Voice Software for Apple iOS

iVoIPEngine – VoIP/SIP Reference Kit for iPHONE®, iPAD®, AND iPOD TOUCH

iVoIPEngine for iPhone is a software package that handles all the processing needed to transform PCM samples to VoIP packets and VoIP packets to PCM samples. In other words, it provides all the voice processing necessary to VoIP-enable an iPhone application.

* formally known as iPVoice

VoIP Engine block diagram

Voice enable your iOS application

iPVoice sample program demonstrates the use of Adaptive Digital's VoIP Engine software in a mobile handset environment.

In particular, the VoIP program, iPVoice turns an iPhone (or iPod or iPad) into a limited capability IP phone. The limitation is that the program communicates via RTP using user specified IP address/port number.

Adaptive Digital's VoIP Engine software is a software engine that handles all the voice processing from PCM to Packet and back. Its intended use is in VoIP enabled handsets or desktop phones.

VoIP Engine has no direct connection to the audio (PCM) source/driver or to the network stack. It simply processes PCM to RTP and RTP to PCM. The VoIP for Apple iOS sample program provides the interfaces to the iOS Audio Driver and to network stack via using UDP/IP. VoIP for Apple interconnects these two interfaces with VoIP Engine, which does the underlying PCM to RTP and RTP to PCM processing.

iVoIPEngine includes a complete suite of Adaptive Digital's CPU and memory efficient fixed-point telephony, VoIP, and voice quality enhancement (VQE) algorithms that enable developers to create toll-quality next generation mobile device applications for iPhone users. iVoIPEngine includes acoustic echo cancellation (AEC), AGC, G.711 with DTX, RTP, tone generation, and network optimization algorithms including packet loss concealment (PLC), and adaptive jitter buffer (AJB). Additionally features can be added such as noise reduction, SIP and a wide variety of compression algorithms including both narrowband and wideband codecs. With the wide variety of Adaptive Digital's fielded voice software at their fingertips, developers can now deliver the highest level of quality voice enabled applications.

Adaptive Digital provides for easy implementation and flexibility through the VoIP Engine API functions. iVoIPEngine brings the same type of ease to a iPhone VoIP developer as is brought by the existing iPhone frameworks that handle other functionality. All the developer needs to do is include the iPVoice library into his or her project and make use of the VoIP Engine API functions. The API functions configure the VoIP Engine as well as handle PCM to Packet and Packet to PCM processing. The processing APIs are designed to interface with the audio I/O and IP stack, which further enhances the developers' flexibility.

The VoIP engine is purely a data processing engine. It has no interface to drivers or peripherals and performs processing solely at the request of the host application. The host application feeds the VoIP engine PCM samples from the audio input and and RTP packets from the network input. The VoIP engine in turn returns, via callbacks to the host application, PCM samples to be sent to the audio output device and RTP packets to be sent to the network interface.

iVoIPEngine includes the following features:

  • Speech Compression
  • Acoustic Echo Cancellation
  • Voice Quality Enhancement -
  • Full Duplex Hands Free support
  • Tone Handling
  • RTP/ Jitter Buffer
  • Speaker Volume Control
  • Test and diagnostic software to assist in acoustical tuning
  • Conferencing
  • SRTP

Additional Features:

Adaptive Digital’s VoIP Engine provides all the voice processing necessary to VoIP-enable an mobile device application.

Adaptive Digital provides customers with expertise in integration and development to enable differentiation of their next gen mobile application.

Optional Software

Compression:  G.726, G.729AB, G.722.2 (AMR WB (Wideband), AMR NB (Narrowband), EVRC-B, MELP

Protocol:  SIP

Network Optimization: Adaptive Jitter Buffer, Packet Loss Concealment (G.711 Appendix 1).


Adaptive Digital brings 17 years of voice/VoIP technology experience to a thus far VoIP-hungry Android market.
Adaptive Digital (easy integration + field proven algorithms) = quick-to-market applications
Hands-free customization available for your Android application
For those who prefer a Hands-dirty approach, a-la-carte algorithms available
Member -Apple iOS Developer Program

Included Software

Voice Quality: Acoustic Echo Cancellation, Noise Reduction

Compression:  G.711 Appendix 1 with PLC (packet loss concealment), and Discontinuous Transmission (G.711 Appendix 2), G.722 WB, G.729

Protocols:  RTP, SRTP

Network Optimization: Adaptive Jitter Buffer, Packet Loss Concealment (G.711 Appendix 1).

Telephony: Tone Generation, Automatic Gain Control

iPVoice SDK (includes an evaluation version of the

VoIP class library, header file and docs)

SIP Phone Sample Project with source code

iPVoice SIP SDK (includesan evaluation version of the SIP class library,
header file and docs)

iPVoice™ demo app featuring SIP is currently available for free download at the App Store.

VoIP Engine phone app Support for G.722 wideband codec has been added. The jitter buffer size is now adaptive based upon measured network jitter.
Conferencing - 3 way testing.

Adaptive Digital’s comprehensive portfolio of speech compression (encode/decode) codecs, voice quality enhancement algoithms, tone generation, and communication protocols provides the Apple Inc.®'s iPhone application developer with the ability to easily bring voice/VoIP to their application.
iPad, iPod, iTouch, and iPhone

» iVoIPEngine (IVE) test software available on the App Store.
Search iPVoice or Adaptive Digital from the App Store on your iPhone (iPad, or iPod Touch) and click download.

» Click here for iPVoice - VoIP Engine/SIP Reference Kit Product Page

Acronyms / Definitions

PCM - Pulse Code Modulation
Receive (Direction) - Data flow from the packet network toward the speaker
Send (Direction) - Data flow from microphone toward packet network
ADT Algos - Adaptive Digital Algorithms
Tone - Tone Generator
RTP - Real-Time Transport Protocol
VoIP  - Voice Over Internet Protocol (IP)
VQE - Voice Quality Enhancement Algorithms
Cocoa® Framework - Apple, Inc.'s libraries, APIs, and runtimes that form the development layer for all of Mac OS® X and iOS

Apple, the Apple logo, iPad, iPhone, and iPod touch are trademarks of Apple Inc., registered in the U.S. and other countries. App Store is a service mark of Apple Inc.

iPVoice, AnVoice, and VoIP Engine are trademarks of Adaptive Digital Technologies, Inc.