Automated Audio Content Analysis Using Convolutional Deep Neural Networks

River is a prototype built as part of my MSc thesis to analyse pre-classified audio samples from radio broadcasts and use this to build a Convolutional Neural Network to predict these classes when presented with further samples from radio broadcasts. This research is to determine if Convolutional Neural Networks are an appropriate method of classifying audio.

River uses Google's TensorBoard open-source Machine Learning library and Librosa to analyse audio signals.

virtualenv -p python3.6 env
source env/bin/activate
pip3 install -r requirements.txt

River analyses audio files in WAVE (.wav) format with filenames like yyyymmdd-aaaa-bb.wav where yyyymmdd is a date/time, aaaa is an integer index, and bb is the zero-indexed class number for this audio sample. The only really important part is the class number but the files should be in the format n-n-n.wav with the last n the class. These should be split into a training and validation set, usually at an 80/20 ratio. This can be done by sampling the files:

To sample at an 80/20 split use a stride of 5 which will move ever 5th file to the target directory. This will create an even distribution of files for the 20% split—the remainder is 80%.

./tf sample_files.py --src=/path/to/wav/input/files/ --stride=2000 --dest=/path/to/wav/output/files/

./tf plot.py --type{wave|spec} --file=/path/to/file1.wav --file=/path/to/file2.wav

Waveform Plot of R&B Track

Spectrogram Plot of R&B Track

Waveform Plot of Speech

Spectrogram Plot of Speech

Extract features found in train and valid subdirectories. Creates training and validation datasets in the data directory

./tf extract.py --dir=/path/to/audio

Use training and validation datasets from the data directory to train a convolutional neural network. Saves model in model directory.

• epochs - number of training iterations
• batch - number of examples to supply in each training epoch
• sample - how often the current cost is returned to the console

./tf train.py --epochs=2000 --batch=50 --sample=10

Logs during training will be created in the log subdirectory, these can be visualised with TensorBoard

Run TensorBoard:

tensorboard --logdir=log/

View results at http://localhost:6006/

Accuracy Plot

Cross Entropy Plot

To use the model built during the Training process to classify audio samples:

./tf audition.py --file=/path/to/filename.wav

...which should yield a class prediction with a confidence score. This filename does not have to be in any particular format as it is only used to encode as a feature and doesn't need a label.

deactivate

To suppress TensorFlow logging, ./tf is used to run the Python code. You could just run python3 however. If you like logging.