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Classify Human Voice Using YAMNet on Android Device

This example shows how to use the Simulink® Support Package for Android™ Devices and a pretrained YAMNet network to classify human voices.


  • For more information on how to use the Simulink Support Package for Android Devices to run a Simulink model on your Android device, see Getting Started with Android Devices.

  • Download and install any ARM® Compute Library using the Hardware Setup screen. This example uses the ARM Compute Library version 20.02.1. For more information on the Hardware Setup Screen, see Install Support for Android Devices.

Required Hardware

  • Android device such as a phone or tablet

  • USB cable

Hardware Setup

Connect your Android device to the host computer using the USB cable.

Download and Unzip Audio Toolbox Support for YAMNet

In MATLAB Command Window, execute these commands to download and unzip the YAMNet model to your temporary directory.

downloadFolder = fullfile(tempdir,'YAMNetDownload');
loc = websave(downloadFolder,'');
YAMNetLocation = tempdir;

Observe the Workspace pane in MATLAB.

Get Human Sounds in AudioSet Ontology

Select only human sounds in the AudioSet ontology. Use the yamnetGraph function to obtain a graph of the AudioSet ontology and a list of all sounds supported by YAMNet. The dfsearch function returns a vector of 'Music' sounds in the order of their discovery using depth-first search.

[ygraph, allSounds] = yamnetGraph;
humanVoice = dfsearch(ygraph,"Human voice");

Find the location of these musical sounds in the list of supported sounds.

[~,HumanVoiceIndices] = intersect(allSounds,humanVoice)
HumanVoiceIndices =

Observe humanVoice and HumanVoiceIndices in the Workspace.

Double-click the humanVoice string from the Workspace or execute this command to view the voices classified under human voices.

humanVoice =
42x1 string array
  "Human voice"
  "Male speech, man speaking"
  "Female speech, woman speaking"
  "Child speech, kid speaking"
  "Narration, monologue"
  "Speech synthesizer"

Configure Simulink Model and Calibrate Parameters

This example uses a preconfigured Simulink model from the Simulink Support Package for Android Devices.

To open the Simulink model, run this command in the MATLAB® Command Window.


Configure ARM Compute Library Version in Simulink Model

  1. In the Modelling tab of the Simulink model, in the Setup section, click Model Settings.

  2. In the Configuration Parameters dialog box, in the left pane, go to Code Generation > Interface.

  3. In the Deep learning section, set ARM Compute Library version to the version you already set in the Hardware Setup screen. In this example, it is set to 20.02.1.

androidClassifyHumanVoice Simulink Model

The output from the Audio Capture block is converted from stereo to mono and then provided to the Sound Classifier block. The sampling frequency and frame size of the audio signal output is 44100 Hz and 4410 Hz, respectively. The YAMNet network requires you to preprocess and extract features from audio signals by converting them to the sample rate the network was trained on (44100 Hz), and then extracting overlapping mel spectrograms. The Sound Classifier block does the required preprocessing and feature extraction that is necessary to match the preprocessing and feature extraction used to train YAMNet. This block detects the scores and labels of the input audio.

Configure these parameters in the Block Parameters dialog box of the Sound Classifier block.

  1. Set Sample rate of input signal (Hz) to 44100.

  2. Set Overlap percentage (%) to 50.

  3. Set Outputs to Predictions.

The Selector in the model picks the scores related to human voices using the vector of indices given by HumanVoiceIndices. In the ClassifyHumanVoice function in the MATLAB Function block, if the maximum value of the scores is greater than 0.2, then the score is related to human voices.

Deploy Simulink Model on Android Device

On the Hardware tab of the Simulink model, in the Mode section, click Run on board. In the Deploy section, click Build, Deploy & Start. The androidClassifyHumanVoice application launches automatically. Speak through the microphone and observe the Dashboard tab of the application. In the Panel section, the type of human voice classified by the YAMNet network is displayed with its probability in the Score section.

The App tab of the application displays the maximum score value of the predicted class.

Similarly, observe the score for different classes of human voices.

Other Things to Try

Google® provides a website where you can explore the AudioSet ontology and the corresponding data set: Explore this data set and classify a wide range of sounds.

See Also