yamnetPreprocess

Preprocess audio for YAMNet classification

Since R2021a

Syntax

features = yamnetPreprocess(audioIn,fs)

features = yamnetPreprocess(audioIn,fs,'OverlapPercentage',OP)

Description

features = yamnetPreprocess(audioIn,fs) generates mel spectrograms from audioIn that can be fed to the YAMNet pretrained network.

features = yamnetPreprocess(audioIn,fs,'OverlapPercentage',OP) specifies the overlap percentage between consecutive audio frames.

For example, features = yamnetPreprocess(audioIn,fs,'OverlapPercentage',75) applies a 75% overlap between consecutive frames used to generate the spectrograms.

Examples

Download YAMNet

Download and unzip the Audio Toolbox™ model for YAMNet.

Type yamnet at the Command Window. If the Audio Toolbox model for YAMNet is not installed, then the function provides a link to the location of the network weights. To download the model, click the link. Unzip the file to a location on the MATLAB path.

Alternatively, execute the following commands to download and unzip the YAMNet model to your temporary directory.

downloadFolder = fullfile(tempdir,'YAMNetDownload');
loc = websave(downloadFolder,'https://ssd.mathworks.com/supportfiles/audio/yamnet.zip');
YAMNetLocation = tempdir;
unzip(loc,YAMNetLocation)
addpath(fullfile(YAMNetLocation,'yamnet'))

Check that the installation is successful by typing yamnet at the Command Window. If the network is installed, then the function returns a SeriesNetwork (Deep Learning Toolbox) object.

yamnet

ans = 
  SeriesNetwork with properties:

         Layers: [86×1 nnet.cnn.layer.Layer]
     InputNames: {'input_1'}
    OutputNames: {'Sound'}

Load Pretrained YAMNet

Load a pretrained YAMNet convolutional neural network and examine the layers and classes.

Use yamnet to load the pretrained YAMNet network. The output net is a SeriesNetwork (Deep Learning Toolbox) object.

net = yamnet

net = 
  SeriesNetwork with properties:

         Layers: [86×1 nnet.cnn.layer.Layer]
     InputNames: {'input_1'}
    OutputNames: {'Sound'}

View the network architecture using the Layers property. The network has 86 layers. There are 28 layers with learnable weights: 27 convolutional layers, and 1 fully connected layer.

net.Layers

ans = 
  86x1 Layer array with layers:

     1   'input_1'                    Image Input              96×64×1 images
     2   'conv2d'                     Convolution              32 3×3×1 convolutions with stride [2  2] and padding 'same'
     3   'b'                          Batch Normalization      Batch normalization with 32 channels
     4   'activation'                 ReLU                     ReLU
     5   'depthwise_conv2d'           Grouped Convolution      32 groups of 1 3×3×1 convolutions with stride [1  1] and padding 'same'
     6   'L11'                        Batch Normalization      Batch normalization with 32 channels
     7   'activation_1'               ReLU                     ReLU
     8   'conv2d_1'                   Convolution              64 1×1×32 convolutions with stride [1  1] and padding 'same'
     9   'L12'                        Batch Normalization      Batch normalization with 64 channels
    10   'activation_2'               ReLU                     ReLU
    11   'depthwise_conv2d_1'         Grouped Convolution      64 groups of 1 3×3×1 convolutions with stride [2  2] and padding 'same'
    12   'L21'                        Batch Normalization      Batch normalization with 64 channels
    13   'activation_3'               ReLU                     ReLU
    14   'conv2d_2'                   Convolution              128 1×1×64 convolutions with stride [1  1] and padding 'same'
    15   'L22'                        Batch Normalization      Batch normalization with 128 channels
    16   'activation_4'               ReLU                     ReLU
    17   'depthwise_conv2d_2'         Grouped Convolution      128 groups of 1 3×3×1 convolutions with stride [1  1] and padding 'same'
    18   'L31'                        Batch Normalization      Batch normalization with 128 channels
    19   'activation_5'               ReLU                     ReLU
    20   'conv2d_3'                   Convolution              128 1×1×128 convolutions with stride [1  1] and padding 'same'
    21   'L32'                        Batch Normalization      Batch normalization with 128 channels
    22   'activation_6'               ReLU                     ReLU
    23   'depthwise_conv2d_3'         Grouped Convolution      128 groups of 1 3×3×1 convolutions with stride [2  2] and padding 'same'
    24   'L41'                        Batch Normalization      Batch normalization with 128 channels
    25   'activation_7'               ReLU                     ReLU
    26   'conv2d_4'                   Convolution              256 1×1×128 convolutions with stride [1  1] and padding 'same'
    27   'L42'                        Batch Normalization      Batch normalization with 256 channels
    28   'activation_8'               ReLU                     ReLU
    29   'depthwise_conv2d_4'         Grouped Convolution      256 groups of 1 3×3×1 convolutions with stride [1  1] and padding 'same'
    30   'L51'                        Batch Normalization      Batch normalization with 256 channels
    31   'activation_9'               ReLU                     ReLU
    32   'conv2d_5'                   Convolution              256 1×1×256 convolutions with stride [1  1] and padding 'same'
    33   'L52'                        Batch Normalization      Batch normalization with 256 channels
    34   'activation_10'              ReLU                     ReLU
    35   'depthwise_conv2d_5'         Grouped Convolution      256 groups of 1 3×3×1 convolutions with stride [2  2] and padding 'same'
    36   'L61'                        Batch Normalization      Batch normalization with 256 channels
    37   'activation_11'              ReLU                     ReLU
    38   'conv2d_6'                   Convolution              512 1×1×256 convolutions with stride [1  1] and padding 'same'
    39   'L62'                        Batch Normalization      Batch normalization with 512 channels
    40   'activation_12'              ReLU                     ReLU
    41   'depthwise_conv2d_6'         Grouped Convolution      512 groups of 1 3×3×1 convolutions with stride [1  1] and padding 'same'
    42   'L71'                        Batch Normalization      Batch normalization with 512 channels
    43   'activation_13'              ReLU                     ReLU
    44   'conv2d_7'                   Convolution              512 1×1×512 convolutions with stride [1  1] and padding 'same'
    45   'L72'                        Batch Normalization      Batch normalization with 512 channels
    46   'activation_14'              ReLU                     ReLU
    47   'depthwise_conv2d_7'         Grouped Convolution      512 groups of 1 3×3×1 convolutions with stride [1  1] and padding 'same'
    48   'L81'                        Batch Normalization      Batch normalization with 512 channels
    49   'activation_15'              ReLU                     ReLU
    50   'conv2d_8'                   Convolution              512 1×1×512 convolutions with stride [1  1] and padding 'same'
    51   'L82'                        Batch Normalization      Batch normalization with 512 channels
    52   'activation_16'              ReLU                     ReLU
    53   'depthwise_conv2d_8'         Grouped Convolution      512 groups of 1 3×3×1 convolutions with stride [1  1] and padding 'same'
    54   'L91'                        Batch Normalization      Batch normalization with 512 channels
    55   'activation_17'              ReLU                     ReLU
    56   'conv2d_9'                   Convolution              512 1×1×512 convolutions with stride [1  1] and padding 'same'
    57   'L92'                        Batch Normalization      Batch normalization with 512 channels
    58   'activation_18'              ReLU                     ReLU
    59   'depthwise_conv2d_9'         Grouped Convolution      512 groups of 1 3×3×1 convolutions with stride [1  1] and padding 'same'
    60   'L101'                       Batch Normalization      Batch normalization with 512 channels
    61   'activation_19'              ReLU                     ReLU
    62   'conv2d_10'                  Convolution              512 1×1×512 convolutions with stride [1  1] and padding 'same'
    63   'L102'                       Batch Normalization      Batch normalization with 512 channels
    64   'activation_20'              ReLU                     ReLU
    65   'depthwise_conv2d_10'        Grouped Convolution      512 groups of 1 3×3×1 convolutions with stride [1  1] and padding 'same'
    66   'L111'                       Batch Normalization      Batch normalization with 512 channels
    67   'activation_21'              ReLU                     ReLU
    68   'conv2d_11'                  Convolution              512 1×1×512 convolutions with stride [1  1] and padding 'same'
    69   'L112'                       Batch Normalization      Batch normalization with 512 channels
    70   'activation_22'              ReLU                     ReLU
    71   'depthwise_conv2d_11'        Grouped Convolution      512 groups of 1 3×3×1 convolutions with stride [2  2] and padding 'same'
    72   'L121'                       Batch Normalization      Batch normalization with 512 channels
    73   'activation_23'              ReLU                     ReLU
    74   'conv2d_12'                  Convolution              1024 1×1×512 convolutions with stride [1  1] and padding 'same'
    75   'L122'                       Batch Normalization      Batch normalization with 1024 channels
    76   'activation_24'              ReLU                     ReLU
    77   'depthwise_conv2d_12'        Grouped Convolution      1024 groups of 1 3×3×1 convolutions with stride [1  1] and padding 'same'
    78   'L131'                       Batch Normalization      Batch normalization with 1024 channels
    79   'activation_25'              ReLU                     ReLU
    80   'conv2d_13'                  Convolution              1024 1×1×1024 convolutions with stride [1  1] and padding 'same'
    81   'L132'                       Batch Normalization      Batch normalization with 1024 channels
    82   'activation_26'              ReLU                     ReLU
    83   'global_average_pooling2d'   Global Average Pooling   Global average pooling
    84   'dense'                      Fully Connected          521 fully connected layer
    85   'softmax'                    Softmax                  softmax
    86   'Sound'                      Classification Output    crossentropyex with 'Speech' and 520 other classes

To view the names of the classes learned by the network, you can view the Classes property of the classification output layer (the final layer). View the first 10 classes by specifying the first 10 elements.

net.Layers(end).Classes(1:10)

ans = 10×1 categorical
     Speech 
     Child speech, kid speaking 
     Conversation 
     Narration, monologue 
     Babbling 
     Speech synthesizer 
     Shout 
     Bellow 
     Whoop 
     Yell 

Use analyzeNetwork (Deep Learning Toolbox) to visually explore the network.

analyzeNetwork(net)

YAMNet was released with a corresponding sound class ontology, which you can explore using the yamnetGraph object.

ygraph = yamnetGraph;
p = plot(ygraph);
layout(p,'layered')

The ontology graph plots all 521 possible sound classes. Plot a subgraph of the sounds related to respiratory sounds.

allRespiratorySounds = dfsearch(ygraph,"Respiratory sounds");
ygraphSpeech = subgraph(ygraph,allRespiratorySounds);
plot(ygraphSpeech)

Preprocess Audio and Classify Sounds with YAMNet

Read in an audio signal.

[audioIn,fs] = audioread('SpeechDFT-16-8-mono-5secs.wav');

Plot and listen to the audio signal.

T = 1/fs;
t = 0:T:(length(audioIn)*T) - T;
plot(t,audioIn);
grid on
xlabel('Time (t)')
ylabel('Ampltiude')

soundsc(audioIn,fs)

Use yamnetPreprocess to extract mel spectrograms from the audio signal. Visualize an arbitrary spectrogram from the array.

melSpectYam = yamnetPreprocess(audioIn,fs);

arbSpect = melSpectYam(:,:,1,randi(size(melSpectYam,4)));
surf(arbSpect,'EdgeColor','none')
view([90,-90])
axis([1 size(arbSpect,1) 1 size(arbSpect,2)])
xlabel('Mel Band')
ylabel('Frame')
title('Mel Spectrogram for YAMNet')
axis tight

Create a YAMNet neural network (This requires Deep Learning Toolbox). Call classify with your YAMNet network and the preprocessed mel spectrogram images.

net = yamnet;
classes = classify(net,melSpectYam);

Classify the audio signal as the most frequently occurring sound.

mySound = mode(classes)

mySound = categorical
     Speech 

Input Arguments

audioIn — Input signal

column vector | matrix

Input signal, specified as a column vector or matrix. If you specify a matrix, yamnetPreprocess treats the columns of the matrix as individual audio channels.

Data Types: single | double

fs — Sample rate (Hz)

positive scalar

Sample rate of the input signal in Hz, specified as a positive scalar.

Data Types: single | double

OP — Overlap percentage between consecutive mel spectrograms

50 (default) | scalar in the range [0,100)

Percentage overlap between consecutive mel spectrograms, specified as a scalar in the range [0,100).

Data Types: single | double

Output Arguments

features — Mel spectrograms that can be fed to YAMNet pretrained network

96-by-64-by-1-by-K array

Mel spectrograms generated from audioIn, returned as a 96-by-64-by-1-by-K array, where:

• 96 –– Represents the number of 25 ms frames in each mel spectrogram

• 64 –– Represents the number of mel bands spanning 125 Hz to 7.5 kHz

• K –– Represents the number of mel spectrograms and depends on the length of audioIn, the number of channels in audioIn, as well as OverlapPercentage

  Note

  Each 96-by-64-by-1 patch represents a single mel spectrogram image. For multichannel inputs, mel spectrograms are stacked along the fourth dimension.

Data Types: single

References

[1] Gemmeke, Jort F., et al. “Audio Set: An Ontology and Human-Labeled Dataset for Audio Events.” 2017 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), IEEE, 2017, pp. 776–80. DOI.org (Crossref), doi:10.1109/ICASSP.2017.7952261.

[2] Hershey, Shawn, et al. “CNN Architectures for Large-Scale Audio Classification.” 2017 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), IEEE, 2017, pp. 131–35. DOI.org (Crossref), doi:10.1109/ICASSP.2017.7952132.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

This function fully supports GPU arrays. For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced in R2021a