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Bird Identification from Timestamped, Geotagged Audio Recordings

This is the implementation of the BirdCLEF 2018 submission by OFAI within the aMOBY project.

It allows training an ensemble of neural networks to recognize 1500 South American bird species in audio recordings, with an option to factor in metadata about the recording date, time and location.

It contains the code for preparing the dataset (converting audio files and parsing metadata), for training a set of different models on audio recordings and/or metadata, for finding weights to form an ensemble of those models, and for producing the predictions on the test set for submission to the challenge.

For a detailed description of the approach, please refer to the paper "Bird Identification from Timestamped, Geotagged Audio Recordings" by Jan Schlüter included in the CLEF Working Notes 2018. [Paper, BibTeX]

Preliminaries

The code requires the following software:

  • Python 2.7+ or 3.4+
  • Python packages: numpy, scipy, Theano, Lasagne
  • bash or a compatible shell
  • ffmpeg

For better performance, the following Python packages are recommended:

  • pyfftw (for much faster spectrogram computation)

Before installing the dependencies, if desired, create and activate an environment using pyenv and/or virtualenv/venv, or using conda.

Install the bleeding-edge versions of Theano and Lasagne from github:

pip install --upgrade --no-deps https://github.com/Theano/Theano/archive/master.zip
pip install --upgrade --no-deps https://github.com/Lasagne/Lasagne/archive/master.zip

(If not in an environment, add --user to install in your home directory, or sudo to install globally.)

For GPU support, also install libgpuarray, following its installation instructions. For a more complete guide including CUDA and cuDNN, please refer to the From Zero to Lasagne guides.

For faster FFTs, install libfftw3 and pyfftw. On Ubuntu, this can be done with:

sudo apt-get install libfftw3-dev
pip install pyfftw

Under conda, it would be:

conda install -c conda-forge pyfftw

Setup

For preparing the experiments, clone the repository somewhere:

git clone https://github.com/f0k/birdclef2018.git

If you do not have git available, download the code from https://github.com/f0k/birdclef2018/archive/master.zip and extract it.

The experiments rely on the BirdCLEF 2018 dataset. First download the files (specifically, BirdCLEF2017TrainingSetPart1.tar.gz, BirdCLEF2017TrainingSetPart2.tar.gz, BirdCLEF2018MonophoneTest.tar.gz, BirdCLEF2018SoundscapesTest.tar.gz, BirdCLEF2018SoundscapesValidation.tar.gz) and extract them to a common directory. If you were not a BirdCLEF participant, ask the organizers if they are willing to share the URLs.

Then open the cloned or extracted repository in a bash terminal and execute the following:

./datasets/birdclef/recreate.sh

It will tell you that you need to specify the path to the extracted files, but it will also display some useful hints on how to organize the placement of the converted audio files. This script will call other scripts to convert the audio to 22 kHz mono files (this saves time during training), build the file lists for training and testing, and extract the ground truth and metadata from the XML files.

Finally, for all following commands, go into the experiments directory:

cd experiments

Training

To train all models for the ensemble, simply run:

./train_all.sh

To use a GPU, either setup a .theanorc file in your home directory, or run:

THEANO_FLAGS=device=cuda,floatX=float32,gpuarray.preallocate=11000 ./train_all.sh

This will train 17 audio, 19 metadata and one combined network(s). On an Nvidia Titan X Pascal GPU, a single training run will take up to 10 hours for audio, and 50 minutes for metadata networks. If your GPU does not have enough memory, reduce or remove the gpuarray.preallocate=11000 setting, and reduce the batch size that is set in the defaults.vars file.

If you have multiple GPUs, you can distribute runs over these GPUs by running the script multiple times in multiple terminals with different target devices, e.g., THEANO_FLAGS=device=cuda1 ./train_all.sh. If you have multiple servers that can access the same directory via NFS, you can also run the script on each server for further distribution of runs (runs are blocked with lockfiles).

The script will also compute network predictions after each training run. If this failed for some jobs for some reasons, run:

./predict_missing.sh

This will compute any missing network predictions (if none are missing, nothing happens).

Evaluation

To obtain results for all networks trained so far, run:

./eval_all.sh

This will print the Mean Average Precision (MAP) against the foreground species, the MAP against the background species, and the top-k accuracy for the foreground species for k between 1 and 5, all on the validation set (the test set is kept secret by the organizers of the BirdCLEF challenge).

Ensembling

After all models have been trained, you can run hyperopt to find an optimal linear combination of models based on the validation set performance. Install it with:

pip install hyperopt

We can now run blender.py to do the actual optimization. The commands are documented in comments in submit_all.sh. For example, for the audio-only ensemble, run:

./blender.py --dataset=birdclef --labelfile-background=bg.tsv --strategy=hyperopt \
  birdclef/{dummy,resnet1}_{lme1,att16,att64}_fdrop05_fM10k_powlearn_shift5_fs1024_mc2cgr1dgr1{,_mixfgbg}{,_ban1}.pred.pkl

In the end, it will produce a list of selected models and combination weights that can be directly copied to submit_all.sh, preceded by submit and a name for the ensemble. It can also be used directly as arguments to ./eval.py to evaluate the ensemble.

Submission

Finally, to create the CSV files for submission, run:

./submit_all.sh

Prefix the command with a THEANO_FLAGS=... setting if needed. This will compute predictions on the test set for all models participating in any of the ensembles, combine the predictions according to the weights, and produce a CSV file for each ensemble.

Reusing

... for different datasets

Datasets can be added to the datasets directory and their name be passed as the --dataset argument of train.py, predict.py, eval.py (and blender.py, if needed). Each dataset directory must contain:

  • an audio subdirectory with .wav files (this is a strict requirement, since they are accessed as memory maps),
  • a filelists directory with at least a train and valid file listing the file names relative to the audio directory, and
  • a labels directory with a fg.tsv file listing the training and validation file names along with their class labels, with a tab character in between, and a labelset file listing all class names to give them a fixed order.

... for different frameworks

The implementation makes some use of features unique to Lasagne, so it is not trivial to port completely to another framework. Some parts may be interesting to take out, though:

  • audio.py contains code for fast spectrogram computation, and a WavFile class for masquerading a .wav files as a numpy array that is lazily mapped to memory when needed.
  • augment.py contains grab_random_excerpts(), which provides a way to yield random excerpts from a set of audio files with wildly different lengths. Each mini-batch will have same-length excerpts, with the length bounded between a given minimum and maximum length, and files drawn from buckets to avoid excessive cropping or padding.
  • model.py contains a learnable mel filterbank, a learnable magnitude transformation, PCEN, and log-mean-exp pooling
  • model_to_fcn.py implements a conversion of a CNN that classifies excerpts to a fully-convolutional network with dilated convolutions and dilated max-pooling that efficiently processes a full recording, keeping the full output resolution