VoIP engine for ARM / Android


Demonstration software for the VoIP Engine products currently available. Contact Sales @ 610-825-0182 x120

Distinguish your product!
VoIP Engine SW: Sound depth and clarity unprecedented in the mobile voice app market.

VoIP Engine for Android: Voice enable your Android application

AnVoice illustration

Adaptive Digital has gathered into one package all of thesoftware
components needed to give high quality voice to your mobile device application.

Mobile phones
  • Speech Compression
  • HD 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
  • Includes JNI application
Full Featured SIP Protocols:
  1. Call Hold
  2. Call Transfer *
  3. Message Waiting *
  4. Conferencing *
  5. Call Initiation
  6. Call Acceptance

* Not currently included in Google Store Demo, should you wish to demo these SIP features, contact sales.


Adaptive Digital’s VoIP Engine for the Android/ARM is a software
package that handles 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 Android/ARM application.

The core of VoIP Engine is an Android native-layer application
that includes a complete suite of Adaptive Digital’s field-proven
telephony, VoIP, and voice quality enhancement algorithms
that enable developers to create toll-quality next generation
mobile applications for Android/ARM users.

Voice enable your Android application

VoIP Engine is supplied with a sample Java application that interfaces to the VoIP Engine native application.

The sample application uses the VoIP Engine API, which in turn uses the Java Native Interface (JNI), to setup an RTP/IP to RTP/IP VoIP connection. Android developers can incorporate the Java sample code into more complete VoIP-enabled Android applications.

Today’s mobile phone applications include an extraordinary amount of functionality. In the Android space in particular, writing software at the native layer is difficult not only due to the complexity of Android but also due to the anarchistic nature of open-source software in general. The best-case scenario for a developer is therefore to work at the Java layer.  But for performance reasons, much functionality needs to run at the native layer.

To make mobile phone application development managable, developers have software many development kits at their fingertips to handle the native layer complexity. Adaptive Digital’s VoIP Engine brings the necessary VoIP functionality to the native layer. All the developer needs to do is access the VoIP engine using a simple API, and package the supplied VoIP Engine native layer application with the end user Android application. By leveraging VoIP Engine, developers can focus on the functionality of the end application without dealing with the complexities of voice processing at the native layer.

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.

Software Architecture

AnVoice block diagram

The Android architecture is divided into two layers – the Java layer and the native layer. With AnVoice, we provide a sample Android application, a JNI wrapper class, and the core VoIP Engine native shared library.

VoIP Engine includes the following features:

PCM Front End (Independently Accessible)

  • HD Acoustic Echo Cancellation
  • Noise Reduction
  • Tone Generation
  • Automatic Gain Control
  • Diagnostics to assist in acoustic tuning
  • Equalization

VoIP Handler

  • G.711 with appendices 1 (packet loss concealment) and 2 (discontinuous transmission)
  • G.729A Vocoder
  • G.722 (wideband audio) with packet loss concealment
  • G.722.2 Vocoder (Optional)
  • AMR Vocoder (Optional)
  • G.722 (wideband audio) with packet loss concealment
  • RTP/Jitter Buffer
  • SRTP
  • DTMF keypress tone relay transmit (IETF RFC2833)


Future enhancements will include:

  • G.729AB (with Appendix B)
  • Plug-in Codecs
AnVoice is available as a VoIP Engine / SIP Reference Kit for Android. The reference kit includes two powerful software development kits (SDKs), VoIP Engine for ARM / Android and SIP providing powerful and highly customizable software environments to quickly add VoIP, and SIP based dial, answer call features into an application.  http://www.adaptivedigital.com/product/VoIP-engine-sdk.htm FREE Download - registration required.


Adaptive Digital brings 20 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 - Arm Solution Center for Android Adaptive Digital develops and licenses Digital Signal Processing (DSP) algorithms and solutions for telephony, audio, and video applications such as VoIP, conferencing, echo-cancellation, and multimedia. Adaptive Digital's extensive software library and open G.PAK™ VoIP framework provide solutions designed, and configured to meet developers' real-world requirements. Adaptive Digital's highly optimized algorithms are offered as linkable object libraries with "C" callable functions or as turnkey DSP solutions. Adaptive Digital's efficient, easy-to-use solutions, result in lower cost and short time-to-market. Additionally we provide support throughout all project phases; customers have access to our technical team directly over the phone or via email. Applications include traditional and IP telephony systems, and VoIP for mobile digital devices (including both Android and iPhone architecture). Adaptive Digital is a member of Texas Instruments' Third Party Developer Network, ARM's Connected Community, and ARM's Solution Center for Android (SCA).

Adaptive Digital (easy integration + field proven algorithms) = quick-to-market applications