VoIP Engine(tm) the One Solution for Android(tm) Mobile VoIP App Development Now With Advanced AEC

July 31, 2012 — Adapaptive Digital Technologies

Plymouth Meeting, PA, July 31, 2012 – With new models of -based mobile handsets and tablets being introduced seemingly on a daily basis, the task of developing reliable, universal, model-independent Voice over IP (VoIP) applications (apps) lies somewhere between daunting and nearly impossible. Adaptive Digital Technologies’ (Adaptive Digital) VoIP Engine, equipped with a self-training acoustic canceller, is about to change that.

Developers of Android applications must consider the many models of devices both currently on the market as well as future product releases when designing their application in order for the app to work well on as many models as possible. In the case when VoIP functionality is part of the application, where voice quality and acoustic (AEC) is of paramount importance, developing an app that works across multiple devices is much trickier. Manually fine tuning the app to each individual model is an unending exercise in futility, leaving you the developer with the task of predicting which devices will bring in the most revenue.

Acoustic echo cancellation is the important must-have component of a VoIP application in today’s hands-free full-duplex communication devices. The Android mobile handset environment is one of the most challenging in which to employ acoustic echo cancellation applications for a number of reasons:

• The many handset models differ widely in acoustics.

• The speaker and microphone are closely spaced, causing a strong feedback path from speaker to microphone.

• Handsets allow users to change the speaker volume and that volume change occurs on the speaker side of the AEC.

• Buffering delay through the audio driver can change not only from model to model but also from one OS version to the next and even from one phone call to the next.

• The many use scenarios of the handheld device such as hands-free, handset, Bluetooth, wired headset, etc. in varying acoustic arenas.

In spite of the challenges that come with mobile handsets, Adaptive Digital set forth to extend its AEC technology to enable it to learn the characteristics of a handset during normal use, store that information, and thereby tune the echo canceller automatically. And the result of this effort is the Self-Training Acoustic Echo Canceller (ST AEC) now an integral part of Adaptive Digital’s fielded VoIP Engine Software.

VoIP Engine the One Solution for Android Mobile VoIP Development: Excellent Voice Quality across all Android based devices. Differentiate your product, save time and resources.

VoIP Engine with the advanced ST AEC takes the tuning work out of the developer’s hands. The VoIP Engine adds voice functionally while providing voice quality and acoustic echo cancellation across Android devices. With the ST AEC in place it is no longer necessary to manually tune your VoIP application to Android-based mobile handset and tablet mode. Once installed in a handset within the VoIP application, the Self-Training AEC maintains a set of profiles for audio interface such as hands-free, handset, Bluetooth, wired headset, etc. The fluid nature of the Self-Training AEC allows it to change, tune itself as necessary, store that information, and essentially learn the acoustic characteristics of the phone in each scenario.

If you are a developer intent on designing an app that doesn’t “just work”, but in developing a solution that achieves superior results, integrate VoIP Engine into your application. The VoIP Engine solution will provide the ultimate listening experience to the end user, and rave reviews for the end product. The ST AEC will self- tune to new devices as they reach the consumers market, thus providing a long-term revenue source for the application developer.


• The ST AEC is based upon Adaptive Digital’s field-tested AEC technology.

• Automatically learns about the acoustics and delay based upon normal conversation.

• Stores and updates tuning statistics with each phone call.

• Requires no manual training on a per-model basis or upon handset OS updates.

• ST AEC is a newly integrated addition to Adaptive Digital’s VoIP Engine for Mobile devices.

About VoIP Engine

The VoIP 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. Although VoIP Engine is not tied to any particular software environment, it was designed with Android and iPhone/iOS in mind.

VoIP Engine includes the following features:

PCM Front End (Independently Accessible)

• Self-Training Acoustic Echo Cancellation

• Tone Generation

• Gain Control

• Automatic Gain Control

• Diagnostics to assist in acoustic tuning

• Equalization

VoIP Handler

• G.711 with appendices 1 (packet loss concealment)

• G.729A Vocoder

• G.722 (wideband audio) with packet loss concealment

• RTP/Jitter Buffer


• DTMF relay transmit (IETF RFC2833)


Future enhancements will include:

• G.711 Appendix 2(discontinuous transmission)

• G.729AB (with Appendix B)

• Plug-in Codecs

For more information relating to VoIP Engine, or our other VoIP Engine based solutions visit, follow links for either AnVoice or ipVoice.

About Adaptive Digital Technologies

Adaptive Digital Technologies is a leading global provider of fully optimized echo cancellation, voice compression, voice quality, audio & video algorithms, and both chips & turnkey solutions for both IP and traditional telecommunications systems / applications, and VoIP for mobile digital devices (including both Android and iPhone architecture).

Adaptive Digital’s solutions support a low-cost product development model with short time-to-market.

For more information concerning Adaptive Digital Technologies, visit or contact sales at 610-825-0182 x120

Topics covered in this article


Subscribe to Android updates