Compandent Mobile application running MELPe Vocoder

Compandent developed highly optimized MELPe STANAG-4591 codec implementation for mobile devices, that requires extremely low computational load and memory.  It also provide a sample implementation that demonstrates the MELPe codec and is very useful for customers who are interested in developing mobile applications.

Compandent MELPe application is now available for download from the Google Play Store. Our Android and iOS applications, demonstrate the quality and speed of our hand optimized MELPe for ARM processors, which can be useful for many Android and iOS applications that require high quality voice in aggressive compression rate, low CPU complexity, and/or transmission over poor reception conditions, where MELPe can outperform perhaps any other vocoder.

Compandent MELPe Android and iOS Application includes the following steps:

  • Play Original Speech button - to play the original speech file (gives you an indication of the original quality and duration)
  • Run 2400 MELPe vocoder button - to run Compandent MELPe encoder & decoder (gives you an indication of how fast it's performed (low CPU complexity) compared to the played file). This step creates an output file and activates the "Play Processed Speech" step.
  • Play Processed Speech button - to play the compressed & decompressed output file created in step 2, and demonstrate the high quality of our MELPe suite.

We would greatly appreciate your review of our MELPe demo application, on the Google Play site.

Figure 1.a Compandent's MELPe Android Application (portrait view) demonstrates our MELPe performance. (c) All rights reserved.

Figure 1.b Compandent's MELPe Android Application (lanscape view) demonstrates our MELPe performance. (c) All rights reserved.

Compandent MELPe  Android application project and source code is provided to our customers as a reference implementation project for developing their own voice applications such as SCIP or TSVCIS based applications.  As shown in Figure 2 below it includes:

  •  the MELPe Native Code library, which was hand optimized for various ARM processors including 64-bit ARMv8a and 32-bit ARMv7a,
  • a Java Native Interface (JNI) C wrapper code demonstrating the initialization, configuration, and lower level calls to the varous functions within the native code MELPe library, and
  • the Main Activity Java and XML files including UI for configuring MELPe codec and calling it from Java.

Figure 2 Compandent's MELPe Android Application layers including the C wrapper and MELPe native code library. (c) All rights reserved.

Compandent MELPe software under Android was used and tested by NATO also as part of the development of Secure Communications Interoperability Protocols (SCIP).

Compandent MELPe software was used in Compandent created testbed device (MELCODER a.k.a. the NATO “gold standard” reference hardware for STANAG-4591) utilized by the NATO's test-laboratory as a part of the MELPe standard adoption process. The software package has passed tests that are similar to the quality and performance tests used in the MELPe development process and/or used in Compandent's MELPe testbed. The same Compandent expertise that contributed to the official NSA MELPe standard has since continued with the development, debugging, and code enhancements at Compandent, bringing the MELPe standard reference to the next level - the Compandent MELPe suite (a.k.a MELPe++ or MELPe-Plus-Plus). Compandent has leveraged its previous experience developing MELPe components for NSA to create a reliable and compliant package that conforms with modern DSP environments & tools.

Compandent also provides MELPe related DSP software & hardware in various COTS form factors and platforms, including multi-channel & multi-thread POSIX (Portable Operating System Interface) compliant software running on various platforms such as Linux, Windows PC, Android, iOS, MacOS, ARM, DSP, GHS, TI, Analog Devices, etc.. Such implementations are suitable for applications such as PDA, pocket PC, laptop, cell-phones, VoIP, satellite communications, secure voice, secure radio, Software Defined Radios (SDR) or software-programmable radio, STE (Secure Terminal Equipment), JTRS and MIDS terminals. Defense Contractors, please also refer to: Note to Defense Contractor Management and Engineering.

For details contact us,Download MELPe Package Fact Sheet MELPe Package Fact Sheet in PDF format , Compandent MELPe FAQ

Please note: Compandent owns intellectual property (IP) in the official (standard) MELPe implementation, and any of its derivatives (see for example USCO certificate of copyright registration numbers: TX0006703781 (postfilt.asm), TX0006845325 (lpc_lib.asm), TX0007161044 (lpc_lib.c), , and many more. Any party intending to develop products based on MELPe should contact Compandent as well as other IP holders regarding licensing.

To report bugs or suggestions to the MELPe algorithm implementation please mail to:


To download the Android MELPe demo application please click (this is a 32-bit ARM is a DSP-based version. A 64-bit ARMv8 is also available by request)

Frequently Asked Questions (FAQ)

Frequently Asked Questions (FAQ) to provide helpful answers to your questions.