Description

You have an audio recording, and you want to know where certain classes of sounds are. SongExplorer is trained to recognize such words by manually giving it a few examples. It will then automatically calculate the probability, over time, of when those words occur in all of your recordings.

Alternatively, you have two or more sets of audio recordings, and you want to know if there are differences between them. SongExplorer can automatically detect sounds in those recordings and cluster them based on how well it can distinguish between them.

Applications suitable for SongExplorer include quantifying the rate or pattern of words emitted by a particular species, distinguishing a recording of one species from another, and discerning whether individuals of the same species produce different song.

Underneath the hood is a deep convolutional neural network. The input is the raw audio stream, and the output is a set of mutually-exclusive probability waveforms corresponding to each word of interest.

Training begins by first thresholding one of your recordings in the time- and frequency-domains to find sounds that exceed the ambient noise. These sounds are then clustered based on similarities in the waveforms for you to manually annotate with however many word labels naturally occur. A classifier is then trained on this corpus of ground truth, and a new recording is analyzed by it. The words it automatically finds are then clustered, this time using the activations of the hidden neurons, and displayed with predicted labels. You manually correct the mistakes, both re-labeling words that it got wrong, as well as labeling words it missed. These new annotations are added to the ground truth, and the process of retraining the classifier and analyzing and correcting new recordings is repeated until the desired accuracy is reached.

Public Domain Annotations

SongExplorer is open source and free for you to use. However, SongExplorer is not a static piece of software. It’s performance is improved with additional high-quality annotations.

Therefore, when you publish results based on SongExplorer, we request that you make all of your primary data and annotations freely available in a recognized data repository, such as figshare, Dryad, or Zenodo. Many journals already require deposition of raw data, but we strongly encourage you to also provide your manual annotations. These manual annotations will serve to improve the performance of SongExplorer over time, helping both your own work and that of everyone else.

Please let us know where you have deposited your raw data and annotations by posting an issue to the SongExplorer repository. We will endeavor to maintain a list of these recordings and annotations in the Citations and Repositories section below.

In addition, consider donating your recordings to a library or museum, like the Cornell Lab of Ornithology's Macauley Library or the Museo de Ciencias Naturales de Madrid's Fonoteca Zoológica.

Publishing your trained models too is also useful to others, for reproducibility at a minimum but also as an example of what hyperparameters work well. Simply compress the entire "logs folder" along with the ".pb" folder inside containing the learned parameters (see Making Predictions below). Be sure to use delete-ckpts to reduce its footprint on disk before distributing it to others.

As an alternative, a list of hyperparameters could suffice, but only if it is complete. At least the following should be included: the length of the context window, a description of each layer including the kernel size, the number of feature maps, strides and dilations if it is convolutional, the type of non-linearity used (e.g. ReLU), whether and where dropout and batch normalization were used, the batch size, the learning rate, the optimizer, the number of training steps, the fraction of data withheld for validation, the version of songexplorer used, the number of trainable parameters (as a sanity check), and, for the curious, the wall clock time that training took and the hardware used (e.g. GPU make and model).

Citations and Repositories

Lee S (2024) Studying Aphid feeding behavior using the Electrical Penetration Graph Janelia Meyerhoff Undergraduate Scholars Symposium

D Ye, JT Walsh, IP Junker, Y Ding (2024) Changes in the cellular makeup of motor patterning circuits drive courtship song evolution in Drosophila bioRxiv

T Wiesner (2023) How good is SongExplorer, a machine learning based classifier, at recognising the electrical signals of Apteronotus leptorhynchus? Bachelor's Thesis, Humboldt Universitat zu Berlin

HM Shiozaki, K Wang, JL Lillvis, M Xu, BJ Dickson, DL Stern (2023) Activity of nested neural circuits drives different courtship songs in Drosophila Nat. Neurosci. bioRxiv

JL Lillvis, K Wang, HM Shiozaki, M Xu, DL Stern, BJ Dickson (2023) Nested neural circuits generate distinct acoustic signals during Drosophila courtship Current Biology bioRxiv figshare

JL Lillvis, H Otsuna, X Ding, I Pisarev, T Kawase, J Colonell, K Rokicki, C Goina, R Gao, A Hu, K Wang, J Bogovic, DE Milkie, L Meienberg, BD Mensh, ES Boyden, S Saalfeld, PW Tillberg, BJ Dickson (2022) Rapid reconstruction of neural circuits using tissue expansion and light sheet microscopy eLife bioRxiv

BJ Arthur, Y Ding, M Sosale, F Khalif, E Kim, P Waddell, S Turaga, DL Stern (2021)
SongExplorer: A deep learning workflow for discovery and segmentation of animal acoustic communication signals
bioRxiv figshare

Notation

Throughout this document Buttons and variables in the SongExplorer graphical user interface (GUI) as well as code are highlighted with backticks. Files and paths are enclosed in double quotes ("..."). The dollar sign ($) in code snippets signifies your computer terminal's command line. Square brackets ([...]) in code indicate optional components, and angle brackets (<...>) represent sections which you much customize.

Installation

SongExplorer can be run on all three major platforms. Installation is as simple as downloading a compressed binary file, unpacking it, and opening a file. If you have a Linux distribution other than Ubuntu, then you might need to use a container (e.g. Docker), as Tensorflow, the machine learning framework from Google that SongExplorer uses, only supports Ubuntu.

Training your own classifier is fastest with a graphics processing unit (GPU). On Linux and Windows you'll need to install the CUDA and CUDNN drivers from nvidia.com. The latter requires you to register for an account. SongExplorer was tested and built with version 12.1. On Macs with Apple silicon processors (i.e. the M series chips), the integrated GPU is accessed via the Metal framework, which comes preinstalled on MacOS.

Downloading Executables

Download the ZIP file specific to your operating system from the Assets section of Songexplorer's Releases page on Github. Then extract its contents, by either right-clicking on the icon, or executing this command in a terminal:

$ unzip songexplorer-<version>-<architecture>.zip

If there are multiple ZIP files ending in a three digit number, download them all and use a decompression program (e.g. 7-zip on MS Windows) that can automatically glue them back together. Github has a 2 GB limit on file size and so sometimes ZIP files must be split.

If on MS Windows you get an error about file paths being too long, edit the registry as follows: press Start and type "regedit" to launch the RegistryEditor, in the left sidebar navigate to "HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Control \ FileSystem", on the right double-click on "LongPathsEnabled", change the value to "1", press Ok, sign out of your account and then back in, and try to decompress again making sure to use 7-zip.

If on MS Windows you get a permissions error when running SongExplorer, execute the following in PowerShell:

> Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

System Configuration

SongExplorer is capable of training a classifier and making predictions on recordings either locally on the host computer, or remotely on a workstation or a cluster. You specify how you want this to work by editing "configuration.py".

Inside you'll find many variables which control where SongExplorer does its work:

$ grep _where= configuration.py
default_where="local"
detect_where=default_where
misses_where=default_where
train_where=default_where
generalize_where=default_where
xvalidate_where=default_where
mistakes_where=default_where
activations_where=default_where
cluster_where=default_where
accuracy_where=default_where
freeze_where=default_where
classify_where=default_where
ethogram_where=default_where
compare_where=default_where
congruence_where=default_where

Each operation (e.g. detect, train, classify, generalize, etc.) is dispatched according to these _where variables. SongExplorer is shipped with each set to "local" via the default_where variable at the top of the configuration file. This value instructs SongExplorer to perform the task on the same machine as used for the GUI. You can change which computer is used to do the actual work either globally through this variable, or by configuring the operation specific ones later in the file. Other valid values for these variables are "server" for a remote workstation that you can ssh into, and "cluster" for an on-premise Beowulf-style cluster with a job scheduler.

Note that "configuration.py" must be a valid Python file.

Scheduling Jobs

Irrespective of where you want to perform your compute, there are additional variables that need to be tailored to your specific resources.

Locally

When running locally SongExplorer uses a custom job scheduler, aitch, to manage the resources required by different tasks. Scheduling permits doing multiple jobs at once, as well as queueing a bunch of jobs for offline analysis. By default, each task reserves all of your computer's CPU cores, GPU cards, and memory, and so only one job can be run at a time. To tailor resources according to your particular data set, and thereby permit multiple jobs to be run simultaneously, you need to specify for each kind of task how much of the system's resources are actually required.

Here, for example, are the default settings for training a model locally:

$ grep train_ configuration.py | head -4
train_where=default_where
train_ncpu_cores=-1
train_ngpu_cards=-1
train_ngigabytes_memory=-1

Let's break this down. The variables ending in ncpu_cores, ngpu_cards, and ngigabytes_memory specify, respectively, the number of CPU cores, number of GPU cards, and number of gigabytes of memory needed, with -1 reserving everything available. For the model in the Tutorial below, this is way overkill, even on the most humble computer, as training only uses two CPU cores and a gigabyte of memory. So in this case you could set train_{ncpu_cores,ngpu_cards,ngigabytes_memory} to 2, 0, and 1, respectively. Doing so would then permit you to train multiple models at once. Alternatively, if you have a GPU, you could set train_{ncpu_cores,ngpu_cards,ngigabytes_memory} to 2, 1, and 1 for this network architecture. As it happens though, training is quicker without a GPU for this model. Moreover, were these latter settings used on a machine with just one GPU, you could only train one model at a time.

Note that these settings don't actually limit the job to that amount of resources, but rather they just limit how many jobs are running simultaneously. It is important not to overburden your computer with tasks, so don't underestimate the resources required, particularly memory consumption. To make an accurate assessment for your particular workflow, use the top and nvidia-smi commands on Unix, the Task Manager on Windows, or the Activity Monitor on Macs to monitor jobs while they are running.

$ top
top - 09:36:18 up 25 days,  1:18,  0 users,  load average: 11.40, 12.46, 12.36
Tasks: 252 total,   1 running, 247 sleeping,   0 stopped,   4 zombie
%Cpu(s):  0.7 us,  0.9 sy, 87.9 ni, 10.4 id,  0.1 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem : 32702004 total,  3726752 free,  2770128 used, 26205124 buff/cache
KiB Swap: 16449532 total, 16174964 free,   274568 used. 29211496 avail Mem 

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
21124 arthurb   20   0 55.520g 2.142g 320792 S 131.2  6.9   1:38.17 python3
    1 root      20   0  191628   3004   1520 S   0.0  0.0   1:20.57 systemd
    2 root      20   0       0      0      0 S   0.0  0.0   0:00.33 kthreadd

The output above shows that a python3 command, which is how a training session appears, is currently using 131.2% of a CPU core (e.g. 1.3 cores), and 6.9% of the 32702004 KiB of total system memory (so about 2.15 GiB).

Use the nvidia-smi command to similarly monitor the GPU card. The same python3 command as above is currently using 4946 MiB of GPU memory and 67% of the GPU cores. Use the watch command to receive repeated updates (i.e. watch nvidia-smi).

$ nvidia-smi
Fri Jan 31 09:35:13 2020       
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 418.39       Driver Version: 418.39       CUDA Version: 10.1     |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  GeForce GTX 980 Ti  Off  | 00000000:03:00.0 Off |                  N/A |
| 22%   65C    P2   150W / 250W |   4957MiB /  6083MiB |     67%      Default |
+-------------------------------+----------------------+----------------------+
                                                                               
+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID   Type   Process name                             Usage      |
|=============================================================================|
|    0     21124      C   /usr/bin/python3                            4946MiB |
+-----------------------------------------------------------------------------+

Another Workstation

Using a lab or departmental server, or perhaps a colleague's workstation remotely, is easiest if you run SongExplorer on it directly and then view the GUI in your own personal workstation's internet browser. To do this, simply ssh into the server and install SongExplorer as described above.

Alternatively, you can run the GUI code (in addition to viewing its output) on your own personal workstation and batch compute jobs to the remote server. This is easiest if there is a shared file system between the two computers. The advantage here is that less compute intensive jobs (e.g. freeze, accuracy) can be run on your workstation. In this case:

Store all SongExplorer related files on the share, including the uncompressed ZIP file or container image, "configuration.py", and all of your data.
Set the PATH environment variable on the remote machine, either directly or by specifying it in SONGEXPLORER_BIN as follows.

On MacOS (and Linux), put this definition in your .bashrc file:

export SONGEXPLORER_BIN='PATH=<path-to-unzipped-executable>/songexplorer/bin:$PATH'

For MS Windows, the equivalent is, in a PowerShell terminal with administrator privileges:

> $tbpath="<path-to-unzipped-executable>"
> [Environment]::SetEnvironmentVariable("SONGEXPLORER_BIN",
        $tbpath + ";" +
        $tbpath + "\bin\songexplorer\src;" +
        $tbpath + "\Library\mingw-w64\bin;" +
        $tbpath + "\Library\usr\bin;" +
        $tbpath + "\Library\bin;" +
        $tbpath + "\Scripts;" +
        $tbpath + "\bin;",
        [EnvironmentVariableTarget]::Machine)
> [Environment]::SetEnvironmentVariable("Path",
        $env:SONGEXPLORER_BIN + $env:Path,
        [EnvironmentVariableTarget]::Machine)

Make the remote and local file paths match by creating a symbolic link. For example, if on a Mac you use SMB to mount as "/Volumes/MyLab" an NSF drive whose path is "/groups/MyLab", then add -[v|B] /groups/MyLab to SONGEXPLORER_BIN and mkdir -p /groups && ln -s /Volumes/MyLab/ /groups/MyLab. With Docker you'll additionally need to open the preferences panel and configure file sharing to bind "/groups".
Set the SONGEXPLORER_BIN environment variable plus the songexplorer alias on both your workstation and the server to point to this same image.
You might need an RSA key pair. If so, you'll need to add -[v|B] ~/.ssh:/root/.ssh to SONGEXPLORER_BIN.
You might need to use ssh flags -i /ssh/id_rsa -o "StrictHostKeyChecking no" in "configuration.py".

If you do not have a shared file system, the SongExplorer image and configuration file must be separately installed on both computers, and you'll need to do all of the compute jobs remotely.

Lastly, update "configuration.py" with the name of the user and IP address of the server. As when doing compute locally, SongExplorer uses a job scheduler on the server to manage resources. The per-task resources used are the same as specified for the local machine in <task>_{ncpu_cores,ngpu_cards,ngigabytes_memory}.

$ grep -A2 \'server configuration.py
# URL of the 'server' computer
server_username="arthurb"
server_ipaddr="c03u14.int.janelia.org"

An On-Premise Cluster

Submitting jobs to a cluster is similar to using a remote workstation, so read the above section first. You might want to even try batching to a another workstation first, as it can be easier to debug problems than doing so on a cluster.

You use your own workstation to view the GUI in a browser, and can either run the GUI code locally or on the cluster. With the former you have the option to submit only a portion of the compute jobs to the cluster, whereas with the latter they must all be performed by the cluster. Running the GUI code on the cluster also requires that the cluster be configured to permit hosting a web page. Moreover, if your cluster charges a use fee, you'll be charged even when the GUI is sitting idle.

As before, it is easiest if there is a shared file system, and if so, all files need to be on it, and the local and remote file paths must be the same or made to be the same with links. The environment variables and aliases must also be the same.

You'll likely need an RSA key pair, possibly need special ssh flags, and definitely need to specify the IP address of the head node and corresponding job submission command and its flags. The best person to ask for help here is your system administrator.

$ grep -A4 \'cluster configuration.py
# specs of the 'cluster'
cluster_username="arthurb"
cluster_ipaddr="login1"
cluster_cmd="bsub -Ne -Pmylab"
cluster_logfile_flag="-oo"

The syntax used to specify the resources required is unique to the particular scheduler your cluster uses and how it is configured. SongExplorer was developed and tested using the Load Sharing Facility (LSF) from IBM. To support any cluster scheduler (e.g. SGE, PBS, Slurm, etc.), SongExplorer ignores <task>_{ncpu_cores,ngpu_cards,ngigabytes_memory} when <task_where> is set to "cluster" and uses the variables <task>_cluster_flags instead to provide maximum flexibility. Instead of specifying the cores, GPUs, and RAM needed explicitly, you give it the flags that the job submission command uses to allocate those same resources.

$ grep -E train.*cluster configuration.py
train_cluster_flags="-n 2 -gpu 'num=1' -q gpu_rtx"
train_cluster_flags="-n 12"

LSF, and maybe other schedulers, does not honor bash's optional variable assignments. So one cannot use SONGEXPLORER_BIN as described in Another Workstation to specify the path to the SongExplorer executable. If modifying your .bashrc file to export a modified PATH is not an option, then specify the -env flag in your configuration.py:

cluster_cmd="bsub -env 'all, PATH=<path-to-unzipped-executable>/songexplorer/bin:<paths-to-everything-else>'"

Tutorial

SongExplorer provides two main workflows. A supervised approach in which you iteratively train a model to output the probabilities over time of specific words of your choosing (yellow curve below). And an unsupervised approach in which the recordings are such that labels can be applied automatically, with the output being how those sounds cluster after a model is trained to distinguish between them (pink curve). This tutorial describes both, starting with the supervised workflow. It's best to read it in it's entirety, but you could also skip to Unsupervised Methods. The blue curve below is described in Discovering Novel Sounds. Video tutorials are also available.

Let's walk through the steps needed to train a classifier completely from scratch.

Recordings need to be monaural 16-bit little-endian PCM-encoded WAV files. They should all be sampled at the same rate, which can be anything. For this tutorial we supply you with Drosophila melanogaster data sampled at 2500 Hz.

First, let's get some data bundled with SongExplorer into your home directory. Using your computer's file browser, create a new folder called "groundtruth-data" with a subfolder inside it called "round1", and copy into there the WAV recording called "PS_20130625111709_ch3.wav" from "/songexplorer/bin/songexplorer/data". Like this on the command line:

$ ls -1 <path-to-unzipped-executable>/songexplorer/bin/songexplorer/data
20161207T102314_ch1-annotated-person1.csv
20161207T102314_ch1.wav*
20190122T093303a-7-annotated-person2.csv*
20190122T093303a-7-annotated-person3.csv*
20190122T093303a-7.wav*
20190122T132554a-14-annotated-person2.csv*
20190122T132554a-14-annotated-person3.csv*
20190122T132554a-14.wav*
Antigua_20110313095210_ch26.wav
PS_20130625111709_ch3-annotated-person1.csv
PS_20130625111709_ch3.wav*

$ mkdir -p groundtruth-data/round1

$ cd <path-to-unzipped-executable>/songexplorer/bin/songexplorer/data
$ cp PS_20130625111709_ch3.wav $PWD/groundtruth-data/round1

Detecting Sounds

Now that we have some data, let's extract the timestamps of some sounds from one of these as-of-yet unannotated audio recordings.

First, start SongExplorer's GUI by right-clicking on OPEN-WITH-TERMINAL.sh (or RUN-WITH-POWERSHELL.ps1 on MS Windows). Like this on the command line:

$ ./OPEN-WITH-TERMINAL.sh
INFO: detected 12 local_ncpu_cores, 1 local_ngpu_cards, 31 local_ngigabytes_memory
SongExplorer version: 27 May 2022 b0c7d5b5452c
arthurb-ws2:5006
2020-08-09 09:30:02,377 Starting Bokeh server version 2.0.2 (running on Tornado 6.0.4)
2020-08-09 09:30:02,381 User authentication hooks NOT provided (default user enabled)
2020-08-09 09:30:02,387 Bokeh app running at: http://localhost:5006/gui
2020-08-09 09:30:02,387 Starting Bokeh server with process id: 1189
2020-08-09 09:30:15,054 404 GET /favicon.ico (10.60.1.47) 1.15ms
2020-08-09 09:30:15,054 WebSocket connection opened
2020-08-09 09:30:15,055 ServerConnection created

The SongExplorer GUI should automatically open in a new tab of your default internet browswer. If not, manually navigate to the URL on the line printed to the terminal immediately below the version information. In the output above this is "arthurb-ws2:5006", which is my computer's name, but for you it will be different. If that doesn't work, try "http://localhost:5006/gui".

On the left you'll see three empty panels (two large squares side by side and three wide rectangles underneath) in which the sound recordings are displayed and annotated. In the middle are buttons and text boxes used to train the classifier and make predictions with it, as well as a file browser and a large editable text box with "configuration.py". On the right is this instruction manual for easy reference.

Click on the Label Sounds button and then Detect. All of the parameters below that are not used in this step will be greyed out and disabled. If all of the required parameters are filled in, the DoIt! button in the upper right will in addition be enabled and turn red.

The first time you use SongExplorer many of the parameters will need to be manually specified. Their values are saved into "songexplorer.state.yml" and are subsequently automatically filled in with their previous values.

In the File Browser, navigate to the WAV file in the "round1/" directory and click on the WAV Files button.

Then specify the eight parameters that control the algorithm used to find sounds. The default values are suitable to the data in this tutorial and so should not need to be changed. If it's not finding sounds though, try making the first number in time σ smaller and/or the first number in freq ρ bigger. If rather it's too sensitive, do the opposite. Conversely, if it's labelling ambient as a sound, make the second number in time σ bigger and the second number in freq ρ smaller. time smooth and freq smooth will fill in small gaps between detected sounds and cull detected sounds that are too short. For further details, see the comments at the top of "time-freq-threshold.py".

Customizing with Plug-ins describes how to use arbitrary custom code of your choosing to detect events should this default algorithm not suit your data.

Once all the needed parameters are specified, click on the red DoIt! button to start detecting sounds. It will turn orange while the job is being asynchronously dispatched, and then back to grey. "DETECT PS_20130625111709_ch3.wav ()" will appear in the status bar. It's font will initially be grey to indicate that it is pending, then turn black when it is running, and finally either blue if it successfully finished or red if it failed.

The result is a file of comma-separated values with the start and stop times (in tics) of sounds which exceeded a threshold in either the time or frequency domain, plus intervals which did not exceed either.

$ grep -m 3 time groundtruth-data/round1/PS_20130625111709_ch3-detected.csv
PS_20130625111709_ch3.wav,2251,2252,detected,time
PS_20130625111709_ch3.wav,2314,2316,detected,time
PS_20130625111709_ch3.wav,2404,2405,detected,time

$ grep -m 3 frequency groundtruth-data/round1/PS_20130625111709_ch3-detected.csv
PS_20130625111709_ch3.wav,113872,114032,detected,frequency
PS_20130625111709_ch3.wav,158224,158672,detected,frequency
PS_20130625111709_ch3.wav,182864,182960,detected,frequency

$ grep -m 3 neither groundtruth-data/round1/PS_20130625111709_ch3-detected.csv
PS_20130625111709_ch3.wav,388,795,detected,neither
PS_20130625111709_ch3.wav,813,829,detected,neither
PS_20130625111709_ch3.wav,868,2201,detected,neither

Manually Annotating

Now we need to manually curate these heuristically detected sounds into a ground truth data set on which to train a classifier.

First, check that the kinds to use and labels to use text boxes are set to "detected" and "time,frequency,neither", respectively. This should have been automatically done when pressing the "Label Sounds" button above.

Then enter into the ground truth textbox the full path to the "groundtruth-data" folder you created above (leaving off the "round1" sub-folder). You can either type it in by hand, or navigate to this folder in the File Browser and click on the ground truth button. You'll see the wide pull-down menu to the left labeled "recording" briefly turn orange, and below that will appear a table showing how many sounds we're detected above.

Then pull down on the "recording" menu on the far left and select the WAV file in which you just detected sounds. In the panel below, the waveform will be plotted along with grey rectangles in the upper half indicating the locations of detected sounds. Pan and zoom through the recording with the buttons labeled with arrows below and to the left. The Play button can be used to listen to the sound, and if the Video button is selected and a movie with the same root basename exists alongside the corresponding WAV file, it will be displayed as well.

To record a manual annotation, first pick a sound that is an unambiguous example of a particular word. Type the word's name into one of the text boxes to the right of the pan and zoom controls and hit return to activate the corresponding counter to its left. Hopefully the chosen sounds was detected and the corresponding gray box in the upper half of the context window nicely demarcates the temporal extent of the word. If so, all you have to do is to double click the grey box itself and it will be extended to the bottom half and your chosen label will be applied. If not, either double-click or click-and-drag in the bottom half of the context window to create a custom time span for a new annotation. In all cases, annotations can be deleted by double clicking any of the gray boxes, or clicking on the "undo" button above.

For this tutorial, choose the words "mel-pulse", "mel-sine", "ambient", and "other". We use the syntax "A-B" here, where A is the species (mel being short for D. melanogaster) and B is the song type. That syntax is not required though-- the labels can be anything of your choosing. The GUI does have a feature, however, to split labels at the hyphen and display groups of words that share a common prefix or suffix.

Training a Classifier

Once you have a few tens of examples for each word, it's time to train a classifier and make some predictions. First, confirm that the annotations you just made were saved into an "-annotated.csv" file in the "groundtruth/" folder.

$ tree groundtruth-data
groundtruth-data
└── round1
    ├── PS_20130625111709_ch3-annotated-<timestamp>.csv
    ├── PS_20130625111709_ch3-detected.csv
    ├── PS_20130625111709_ch3-detect.log
    └── PS_20130625111709_ch3.wav

$ tail -5 groundtruth-data/round1/PS_20130625111709_ch3-annotated-<timestamp>.csv
PS_20130625111709_ch3.wav,470151,470719,annotated,mel-sine
PS_20130625111709_ch3.wav,471673,471673,annotated,mel-pulse
PS_20130625111709_ch3.wav,471752,471752,annotated,mel-pulse
PS_20130625111709_ch3.wav,471839,471839,annotated,mel-pulse
PS_20130625111709_ch3.wav,492342,498579,annotated,ambient

Click on the Make Predictions button to disable the irrelevant actions and fields, and then the Train button. Using the File Browser, set Logs Folder to a directory in which to put the trained model (e.g. "trained-classifier1") and Ground Truth to the folder one level up in the file hierarchy from the WAV and CSV files (i.e. "groundtruth-data" in this case). One hundred steps suffices for this amount of ground truth. So we can accurately monitor the progress, withhold 40% of the annotations to validate on, and do so every 10 steps. Enter these values into the # steps, validate %, and validate period variables. Check that the labels to use variable is set to "mel-pulse,mel-sine,ambient,other", and kinds to use is "annotated" so that SongExplorer will ignore the detected annotations in the Ground Truth directory. Note that the total number of annotations must exceed the size of the mini-batches, which is specified by the mini-batch variable. The rest of the fields, most of which specify the network architecture, are filled in with default values the first time you ever use SongExplorer, and any changes you make to them, along with all of the other text fields, are saved to a file named "songexplorer.state.yml" in the directory specified by "state_dir" in "configuration.py".

Now press DoIt!. Output into the log directory are "train1.log", "train_1r.log", and "train_1r/". The former two files contain error transcripts should any problems arise, and the latter folder contains checkpoint files prefixed with "ckpt-" which save the weights of the neural network at regular intervals.

With small data sets the network should just take a minute or so to train. As your example set grows, you might want to monitor the training progress as it goes:

$ watch tail trained-classifier1/train_1r.log
Every 2.0s: tail trained-classifier1/train_1.log      Fri Jun 3 14:37:31 2022

39.697532,9,75.8,0.947476
43.414184,10,84.4,0.871244
Saving to "/home/arthurb/songexplorer/trained-classifier1/train_1k/ckpt-10"
Confusion Matrix:
 ['mel-pulse', 'mel-sine', 'ambient']
 [[26  9  9]
 [ 0  4  0]
 [ 0  0  4]]
45.067488,10,65.4 Validation 
48.786851,11,79.7,0.811077

It is common for the accuracy, as measured on the withheld data and reported as "Validation accuracy" in the log file above, to be worse than the training accuracy. If so, it is an indication that the classifier does not generalize well at that point. With more training steps and more ground-truth data though the validation accuracy should become well above chance.

Quantifying Accuracy

Measure the classifier's performance using the Accuracy button. For the purposes of this tutorial, leave the P/Rs textbox (short for Precision / Recall ratio) set to the default value of "1.0" so that the false positives and false negatives are equally weighted. In future, if, say, minimizing false positives in your experiments is important, and you are tolerant of a few more false negatives, you can set it to say "10" (or "0.1" if vice versa).

Output are the following charts and tables in the logs folder and the train_1r subdirectory therein:

"train-validation-loss.pdf" shows the loss value and training and validation recalls as a function of the number of training steps, wall-clock time, and epochs. Should the curves not quite plateau, choose a checkpoint to restore from, increase # steps, and train some more. If you've changed any of the parameters, you'll need to first reset them as they were, which is made easy by selecting one of the original log files and pressing the Copy button.
"confusion-matrix.pdf" shows the confusion matrix of the most accurate checkpoint. Each annotation is placed in this two-dimensional grid according to the label it was manually assigned and the label it was automatically predicted to be. For a perfect classifier this matrix would be diagonal-- that is, the upper left to lower right boxes would be bright yellow and all others dark purple.

The F1 score, which is the product divided by the sum of the precision and recall, times two, is taken to be the "most accurate checkpoint". In this particular case, there is only one model, but in Measuring Generalization and Searching Hyperparameters we'll train multiple models. In those cases, the sum of the confusion matrices with the best F1s for each model is shown here. Multiple models are also created if # replicates is greater than 1.

If there are ten or fewer labels, the squares are large enough to annotate them in the middle with the total number of annotations falling into this square. The number in the upper right triangle in each square is the number of annotations in this square divided by the number of annotations in this row. For boxes along the diagonal it indicates the recall for that label, which is the percentage of true positives among all real events (true positives plus false negatives). Similarly in the lower left is the precision-- the percentage of true positives among all (both true and false) positives. It is calculated by dividing the numbers in the upper right corner of each box by the sum of the corresponding column. In the title are the overall precision and recall, which are calculated as the average of the lower left and upper right numbers along the diagonal.
In the left panel of "precision-recall.pdf" is the precision and recall for each label plotted separately. These are simply the values in the corners of the boxes along the diagonal of the confusion matrix. For a perfect classifier they would all be 100. In this case all of the circles have black perimeters because this logs folder contains just a single trained model, but in the case where there are multiple models in this logs folder each will have it's own point here calculated from their individual confusion matrices. The model-specific circles will be smaller and have white perimeters, with the larger circles outlined in black being the average across models.

Similarly in the right panel of "precision-recall.pdf" is the precision and recall for each model (as opposed to label) plotted separately. Small circles with white perimeters show the label-specific accuracies and larger circles with black perimeters show the average across labels for each model.
"P-R-F1-label.pdf" plots validation precision, recall, and the F1 score over time in the top, middle, and bottom rows respectively with a separate column for each label. Check here to make sure that the accuracy of each label has converged. If there is more than one model in this logs folder, the thin colored lines are the accuracies for each model, with the thick black line being the average across models. "P-R-F1-model.pdf" is similar, but the columns are the models and the thin colored lines the labels. Averages across all labels and models are plotted in "P-R-F1-average.pdf".
"PvR.pdf" plots, separately for each label and model, the trajectory of the validation precision versus recall curve over number of training steps. The leftmost column and topmost row show the averages across models and labels, respectively, with the upper left plot showing the average across all models and labels.
"train_1r/confusion-matrix.ckpt-*.csv" shows the confusion matrices for each checkpoint.
"train_1r/thresholds.ckpt-*.csv" lists the label-specific probability thresholds that are used to achieve the precision-recall ratio specified in the P/Rs textbox. One of these files is used when creating ethograms (see Making Predictions).
"train_1r/precision-recall.ckpt-*.pdf" and "train_1r/sensitivity-specificity.ckpt-*.pdf" show how the ratio of false positives to false negatives changes as the threshold used to call an event changes. The areas underneath these curves are widely-cited metrics of performance. The actual threshold used is indicated in red. Higher thresholds result in more false negatives, and so would be further up and to the left on this curve.
"train_1r/probability-density.ckpt-*.pdf" shows, separately for each label, histograms of the values of the classifier's output taps across all of that label's annotations. The difference between a given label's probability distribution and the second most probable label can be used as a measure of the classifier's confidence. The dashed vertical black line is the threshold used for this label.
The CSV files in the "train_1r/predictions.ckpt-*" directory list the specific annotations in the withheld validation set which were misclassified (plus those that were correct). The WAV files and time stamps therein can be used to look for patterns in the raw data (see Examining Errors).

Making Predictions

For the next round of manual annotations, we're going to have this newly trained classifier find sounds for us instead of using a simple threshold. And we're going to do so with a different recording so that the classifier learns to be insensitive to experimental conditions.

First let's get some more data bundled with SongExplorer into your home directory. Make a new subfolder in "groundtruth-data" called "round2". Then copy "20161207T102314_ch1.wav" from "/songexplorer/bin/songexplorer/data" into there. Like this on the command line:

$ mkdir groundtruth-data/round2

$ cd <path-to-unzipped-executable>/songexplorer/bin/songexplorer/data
$ cp 20161207T102314_ch1.wav $PWD/groundtruth-data/round2

Use the Freeze button to save the classifier's neural network graph structure and weight parameters into the file format that TensorFlow needs for inference. You'll need to tell it which model to use by selecting the last checkpoint file in the classifier's log files with the File Browser (i.e. one of "trained-classifier1/train_1r/ckpt-100.{index,data*}" in this case). Output into the log files directory are "freeze.ckpt-*.log" and "frozen-graph.ckpt-*.log" files for errors, and a "frozen-graph.ckpt-*.pb/" folder containing the binary data. This latter PB folder, or the "saved_model.pb" file therein, can in future be chosen as the model instead of a checkpoint file.

Now use the Classify button to generate probabilities over time for each annotated label. Specify which recordings using the File Browser and the WAV Files button. Note that while the "Checkpoint File" button changed to "PB File", you can leave the text box as is; all SongExplorer needs is a filename from which it can parse "ckpt-*". The probabilities for each label are stored in separate WAV files, with the label appended as a suffix:

$ ls groundtruth-data/round2/
20161207T102314_ch1-ambient.wav    20161207T102314_ch1-mel-sine.wav
20161207T102314_ch1-classify.log   20161207T102314_ch1-other.wav
20161207T102314_ch1-mel-pulse.wav  20161207T102314_ch1.wav

Discretize these probabilities using thresholds based on a set of precision-recall ratios using the Ethogram button. Choose one of the "thresholds.ckpt-*.csv" files in the log files folder using the File Browser. These are created by the Accuracy button and the values therein are controlled by the P/Rs variable at the time you quantified the accuracy. For convenience you can also just leave this text box as it was when freezing or classifying; all SongExplorer needs is a filename in the logs folder from which in can parse "ckpt-*". You'll also need to specify which ".wav" files to threshold using the WAV Files button. Again, for convenience, you can leave this as it was when classifying, as what is needed here is the ".wav" file of the raw recording, not those containing the label probabilities.

$ ls -t1 groundtruth-data/round2/ | head -2
20161207T102314_ch1-ethogram.log
20161207T102314_ch1-predicted-1.0pr.csv

$ head -5 groundtruth-data/round2/20161207T102314_ch1-predicted-1.0pr.csv 
20161207T102314_ch1.wav,19976,20008,predicted,mel-pulse
20161207T102314_ch1.wav,20072,20152,predicted,mel-sine
20161207T102314_ch1.wav,20176,20232,predicted,mel-pulse
20161207T102314_ch1.wav,20256,20336,predicted,mel-sine
20161207T102314_ch1.wav,20360,20416,predicted,mel-pulse

The resulting CSV files are in the same format as those generated when we detected sounds in the time and frequency domains as well as when we manually annotated words earlier using the GUI. Note that the fourth column distinguishes whether these words were detected, annotated, or predicted.

Correcting False Alarms

In the preceding section we generated a set of predicted sounds by applying word-specific thresholds to the probability waveforms:

$ cat trained-classifier/thresholds.csv 
precision/recall,1.0
mel-pulse,0.508651224000211
mel-sine,0.9986744484433365
ambient,0.9997531463467944

Higher thresholds result in fewer false positives and more false negatives. A precision-recall ratio of one means these two types of errors occur at equal rates. Your experimental design drives this choice.

Let's manually check whether our classifier in hand accurately calls sounds using these thresholds. First, click on the Fix False Positives button. Double check that the kinds to use variable was auto-populated with "annotated,predicted".

Use the Activations button to save the input to the neural network as well as its hidden state activations and output logits by classifying the predicted sounds with the trained network. The time and amount of memory this takes depends directly on the number and dimensionality of detected sounds. To limit the problem to a manageable size one can use max sounds to randomly choose a subset of samples to cluster. So that words with few samples are not obscured by those with many, one can randomly subsample the latter by setting equalize ratio to a small integer. Output are three files in the Ground Truth directory: "activations.log", "activations-samples.log", and "activations.npz". The two ending in ".log" report any errors, and the ".npz" file contains the actual data in binary format.

Now reduce the dimensionality of the hidden state activations to either two or three dimensions with the Cluster button. By default, Songexplorer uses the UMAP algorithm (McInnes, Healy, and Melville (2018)), but tSNE and PCA can be used instead via a plugin (see Clustering Algorithm). For now, leave the neighbors and distance parameters set to their default values. A description of how they change the resulting clusters can be found in the aforementioned article. Also leave the PCA fraction parameter at its default. In future, if you find clustering slow for larger data sets, UMAP can be preceded by PCA, and the fraction of coefficients that are retained is specified using PCA fraction. Lastly, choose to cluster just the last hidden layer using the "layers" multi-select box. Output are two or three files in the Ground Truth directory: "cluster.log" contains any errors, "cluster.npz" contains binary data, and "cluster-pca.pdf" shows the results of the principal components analysis (PCA) if one was performed.

Finally, click on the Visualize button to render the clusters in the left-most panel. Adjust the size and transparency of the markers using the Dot Size and Dot Alpha sliders respectively. There should be some structure to the clusters even at this early stage of annotation.

To browse through your recordings, click on one of the more dense areas and a fuchsia circle (or sphere if the clustering was done in 3D) will appear. In the right panel are now displayed snippets of predicted waveforms which are within that circle. The size of the circle can be adjusted with the Circle Radius slider and the number of snippets displayed with gui_snippet_n{x,y} in "configuration.py". The snippets should exhibit some similarity to one another since they are neighbors in the clustered space. They will each be labeled "predicted mel-pulse", "predicted mel-sine", or "predicted ambient" to indicate which threshold criterion they passed and that they were predicted (as opposed to annotated, detected, or missed; see below). The color is the scale bar-- yellow is loud and purple is quiet. Clicking on a snippet will show it in greater temporal context in the wide context panel below.

Now let's correct the mistakes! Select predicted and ambient from the kind and no hyphen pull-down menus, respectively, and then click on a dense part of the cluster plot. Were the classifier perfect, all the snippets now displayed would look like background noise. Click on the ones that don't and manually annotate them appropriately as before. One can also simply double click on the snippet to create a new annotation, and double-click it again to change your mind. Similarly select mel- and -pulse from the species and word pull-down menus and correct any mistakes, and then mel- and -sine.

Keep in mind that the only words which show up in the clusters are those that exceed the chosen threshold. Any mistakes you find in the snippets are hence strictly false positives.

Correcting Misses

It's important that false negatives are corrected as well. One way to find them is to click on random snippets and look in the surrounding context in the window below for sounds that have not been predicted. This method is cumbersome in that you have to scan through the recording. A better way is to directly home in on detected sounds that don't exceed the probability threshold.

To systematically label missed sounds, first click on the Fix False Negatives button. Then detect sounds in the recording you just classified, using the Detect button as before, and create a list of the subset of these sounds which were not assigned a label using the Misses button. For the latter, you'll need to specify both the detected and predicted CSV files with the File Browser and the WAV Files button. The result is another CSV file, this time ending in "missed.csv":

$ head -5 groundtruth-data/round2/20161207T102314_ch1-missed.csv 
20161207T102314_ch1.wav,12849,13367,missed,other
20161207T102314_ch1.wav,13425,13727,missed,other
20161207T102314_ch1.wav,16105,18743,missed,other
20161207T102314_ch1.wav,18817,18848,missed,other
20161207T102314_ch1.wav,19360,19936,missed,other

Now visualize the hidden state activations-- Double check that the label types variable was auto-populated with "annotated,missed" by the Fix False Negatives button, and then use the Activations, Cluster, and Visualize buttons in turn.

Examine the false negatives by selecting missed in the kind pull-down menu and click on a dense cluster. Were the classifier perfect, none of the snippets would be an unambiguous example of any of the labels you trained upon earlier. Annotate any of them that are, and add new label types for sound events which fall outside the current categories.

Minimizing Annotation Effort

From here, we just keep alternating between annotating false positives and false negatives, using a new recording for each iteration, until mistakes become sufficiently rare. The most effective annotations are those that correct the classifier's mistakes, so don't spend much time, if any, annotating what it got right.

Each time you train a new classifier, all of the existing "predicted.csv", "missed.csv", and word-probability WAV files are moved to an "oldfiles" sub-folder as they will be out of date. You might want to occasionally delete these folders to conserve disk space:

$ rm groundtruth-data/*/oldfiles*

Ideally a new model would be trained after each new annotation is made, so that subsequent time is not spent correcting a prediction (or lack thereof) that would no longer be made in error. Training a classifier takes time though, so a balance must be struck with how quickly you alternate between annotating and training.

Since there are more annotations each time you train, use a proportionately smaller percentage of them for validation and proportionately larger number of training steps. You don't need more than ten-ish annotations for each word to confirm that the learning curves converge, and a hundred-ish suffice to quantify accuracy. Since the learning curves generally don't converge until the entire data set has been sampled many times over, set # steps to be several fold greater than the number of annotations (shown in the table near the labels) divided by the mini-batch size, and check that it actually converges with the "train-validation-loss.pdf", "validation-P-R-F1*.pdf", and "validation-PvR.pdf" figures generated by the Accuracy button. If the accuracy converges before an entire epoch has been trained upon, use a smaller learning rate.

As the wall-clock time spent training is generally shorter with larger mini-batches, set it as high as the memory in your GPU will permit. Multiples of 32 are generally faster. The caveat here is that exceedingly large mini-batches can reduce accuracy, so make sure to compare it with smaller ones.

One should make an effort to choose a recording at each step that is most different from the ones trained upon so far. Doing so will produce a classifier that generalizes better.

Once a qualitatively acceptable number of errors in the ethograms is achieved, quantitatively measure your model's ability to generalize by leaving entire recordings out for validation (see Measuring Generalization). Use cross validation to maximize the accuracy by fine tuning the hyperparameters (see Searching Hyperparameters). Then train a single model with nearly all of your annotations for use in your experiments. Optionally, use # replicates to train multiple models with different batch orderings and initial weights to measure the variance. These replicate models can also be combined into an ensemble model (see Ensemble Models) for even greater accuracy. Finally, report accuracy on an entirely separate set of densely-annotated test data(see Testing Densely).

Double Checking Annotations

If a mistake is made annotating, say the wrong label is applied to a particular time interval, and you notice this immediately, use the Undo button to correct it.

Sometimes though, mistakes might slip into the ground truth and a model is trained with them. These latter mistakes can be corrected in a fashion similar to correcting false positives and false negatives. Simply cluster the hidden state activations using the Activations, Cluster, and Visualize buttons as before making sure that "annotated" is in kinds to use. Then click on annotated in the kind pull-down menu and select one of your labels (e.g. mel- in species and -pulse in word). Scan through the visualized clusters by clicking on several points and looking at the snippets therein. If you find an error, simply choose the correct label in one of the text boxes below and then double click on either the snippet itself or the corresponding gray box in the upper half of the wide context window. If you want to remove the annotation entirely, choose a label with an empty text box and double-click. In both cases, the entry in the original "annotated.csv" file is removed, and in the former case a new entry is created in the current "annotated.csv" file. Should you make a mistake while correcting a mistake, simply Undo it, or double click it again. In this case, the original CSV entry remains deleted and the new one modified in the current "annotated.csv" file.

Measuring Generalization

Up to this point we have validated on a small portion of each recording. Once you have annotated many recordings though, it is good to set aside entire WAV files to validate on. In this way we measure the classifier's ability to extrapolate to different microphones, individuals, or whatever other characteristics that are unique to the withheld recordings.

To train one classifier with a single recording or set of recordings withheld for validation, first click on Generalize and then Omit All. Use the File Browser to either select (1) specific WAV file(s), (2) a text file containing a list of WAV file(s) (either comma separated or one per line), or (3) the Ground Truth folder or a subdirectory therein. Finally press the Validation Files button and DoIt!.

To train multiple classifiers, each of which withholds a single recording in a set you specify, click on Omit One. Select the set as described above for Omit All. The DoIt! button will then iteratively launch a job for each WAV file that has been selected, storing the result in the same Logs Folder but in separate files and subdirectories that are suffixed with the letter "w". Of course, training multiple classifiers is quickest when done simultaneously instead of sequentially. If your model is small, you might be able to fit multiple on a single GPU (see the models_per_job variable in "configuration.py"). Otherwise, you'll need a machine with multiple GPUs, access to a cluster, or patience.

A simple jitter plot of the accuracies on withheld recordings is included in the output of the Accuracy button (right panel of "accuracy.pdf"). It will likely be worse than a model trained on a portion of each recording. If so, label more data, or try modifying the hyperparameters (Searching Hyperparameters)

Searching Hyperparameters

Achieving high accuracy is not just about annotating lots of data, it also depends on choosing the right model architecture. While there is a lot of art in finding the best one, an intuition can be learned by [https://github.com/google-research/tuning_playbook](systematically searching) the space of hyperparameters. SongExplorer by default uses convolutional neural networks, and there are many free parameters by which to tune its architecture. You configure them by editing the variables itemized below, and then use cross-validation to compare different choices. Customizing with Plug-ins describes how to use arbitrary custom networks of your choosing should convolutions not suit your task.

context is the temporal duration, in milliseconds, that the classifier inputs
shift by is the asymmetry, in milliseconds, of context with respect to the point in time that is annotated or being classified. shift by divided by stride (see below) should be an integer. For positive values the duration of the context preceding the annotation is longer than that succeeding it.
optimizer can be one of Adadelta, AdaGrad, Adam, Adamax, Ftrl, Nadam, RMSProp, or stochastic gradient descent (SGD).
learning rate specifies the fraction of the gradient to change each weight by at each training step. Set it such that the training curve accuracy in "train-validation-loss.pdf" does not saturate until after at least one epoch of ground truth has been trained upon.

The above apply to all architectures. Specific to the default convolutional network architecture plugin are:

representation specifies whether to use the raw waveform directly, to make a spectrogram of the waveform to input to the neural network, or to use a mel-frequency cepstrum (see Davis and Mermelstein 1980; IEEE). Waveforms do not make any assumptions about the data, and so can learn arbitrary features that spectrograms and cepstrums might be blind to, but need more annotations to make the training converge.
window is the length of the temporal slices, in milliseconds, that constitute the spectrogram. window / 1000 * audio_tic_rate is the window length in tics and should round down to a power of two.
stride is the time, in milliseconds, by which the windows in the spectrogram are shifted. 1000/stride must be an integer multiple of the downsampling rate achieved by stride after.
range (Hz) controls the frequency band of the spectrogram to use. If left blank, the entire range from 0 to the Nyquist frequency is used by the neural network. Specify a sub-band in Hertz if desired with the low and high frequency bounds separated by a hyphen.
mel & DCT controls the frequency resolution of the mel-frequency cepstrum. The first number specifies how many frequencies to use when resampling the linear-frequency spectrogram into mel-frequency space, and the second is how many of the lowest frequency coefficients to keep after the subsequent discrete cosine transform. The second number should always be less than or equal to the first, and neither should greatly exceed the number of frequencies in the original spectrogram, which is one plus half of the window length in tics.
# conv layers is an integer specifying the number of convolutional layers. dense layers is a comma-separated list of integers specifying the number of hidden units in a sequence of optional dense layers after the convolutions. Leave it blank to not add any dense layers.
kernels specifies the size of the convolutional kernels in the form "T1xF,T2". When representation is "waveform", the values before the comma are ignored and 1D convolutions of width T2 are repeatedly applied until the remaining unpadded tensor length is less that T2 or # conv layers has been reached. For "spectrogram" and "mel-cepstrum", the string before the comma is the size of the 2D convolutions in time (T1) and frequency (F) that are repeatedly used for each layer until the remaining unpadded tensor size is smaller than this kernel in one or both dimensions. Then full-height (i.e. pan-frequency) 1D convolutions are repeatedly applied whose width in time is T2. No further convolutional layers are added if # conv layers is reached, or the width in time becomes less than the second number in kernels.
# features is the number of feature maps to use at each of the corresponding stages in kernels. See LeCun et al (1989; Neural Computation).
stride time and stride freq specify the layers, starting from zero, at which to stride the convolutional kernels by two in the time and frequency axes, respectively. The format is a comma-separated list of integers, possibly prefixed with an inequality, or a hyphenated range. For example, "1,2,3,5,6,7", "1-3,5-7", and "<=3,>=5" are all valid and equivalent. Striding in time downsamples the output tic rate.
dilate time and dilate freq similarly specify the layers at which to dilate the convolutional kernels. See Yu and Koltun (2016; arXiv). Striding and dilation can not be both done in the same layer.
if pool kind is other than none, a maximum or average pooling layer is added before the final dense layer(s) whose size and stride are identical and specified by pool size. The latter is of the form "T,F" where T is the size and stride in time and F that in frequency.
connection specifies whether to use identity bypasses, which can help models with many layers converge. See He, Zhang, Ren, and Sun (2015; arXiv.
dropout % is the percentage of hidden units on each forward pass to omit during training. See Srivastava, Hinton, et al (2014; J. Machine Learning Res.). dropout kind specifies whether to omit entire feature maps at a time, or to omit individual neurons separately. See Tompson, Foroshin, et al (2014; arXiv:1411.4280v3).
augment volume is the range within which to uniformly pick a random number to muliply each waveform by.
augment noise is the range within which to uniformly pick a random number to use as the standard deviation of a Gaussian distribution which is added to each waveform.
normalization specifies whether to normalize each mini-batch of samples before or after the non-linearity in each layer, either across the entire batch dimension or in groups across the channel dimension. See Ioffe and Szegedy (2015; arXiv:1502.03167v3) and Wu and He (2018; arXiv:1803.08494v3).

There is also:

weights seed specifies whether to randomize the initial weights or not. A value of -1 results in different values for each fold. They are also different each time you run x-validate. Any other number results in a set of initial weights that is unique to that number across all folds and repeated runs.
batch seed similarly specifies whether to randomize the order in which samples are drawn from the ground-truth data set during training. A value of -1 results in a different order for each fold and run; any other number results in a unique order specific to that number across folds and runs.

To perform a simple grid search for the optimal value of a particular hyperparameter, first choose how many folds you want to partition your ground-truth data into using k-fold. More folds permit characterizing the variance better, but take longer to train and also result in fewer annotations to measure the accuracy. Ensure that you have at least 10 annotations for each label in the validation set if using many folds. Then set the hyperparameter of interest to the first value you want to optimize and use the name of the hyperparameter and it's value as the Logs Folder (e.g. "mb64" for a mini-batch size of 64). Suffix any additional hyperparameters of interest using underscores (e.g. "mb64_ks129_fm64" for a kernel size of 129 and 64 feature maps). If your model is small, use models_per_job in "configuration.py" to train multiple folds on a GPU. Click the X-Validate button and then DoIt!. One classifier will be trained for each fold, using it as the validation set and the remaining folds for training. Separate files and subdirectories are created in the Logs Folder that are suffixed by the fold number and the letter "k". Plot training curves with the Accuracy button, as before. Repeat the above procedure for each of remaining hyperparameter values you want to try (e.g. "mb128_ks129_fm64", "mb256_ks129_fm64", etc.). Then use the Compare button to create a figure of the cross-validation data over the hyperparameter values, specifying for the Logs Folder the independent variable (e.g. "mb") suffixed with the fixed hyperparameters of interest (e.g. "mb_ks128_fm64"). Output are three files:

"[prefix]-compare-confusion-matrices.pdf" contains the summed confusion matrix for each of the values tested.
"[prefix]-compare-overall-params-speed.pdf" plots the accuracy, number of trainable parameters, and training time for each model.
"[prefix]-compare-precision-recall.pdf" shows the final error rates for each model and wanted word.

Training multiple models like this with the same hyperparameters is not only useful for quantifying the variability in the accuracy, but can also be used to reduce that same variability by averaging the outputs across all of the folds. Ensemble Models describes how to do just this by combining multiple models into a single one.

Limiting Ground Truth

If no amount of hyperparameter optimization improves the accuracy to your satisfaction, you might just need more ground truth annotations. To predict whether more ground truth will help, train a model using only a fraction of what is currently available and compare the accuracy to a model which uses all of it. In this way you can extrapolate whether it would be worth spending the time to annotate.

The cross validation procedures used in the previous section (Searching Hyperparameters) makes limiting ground truth in this way easy. Simply specify a k-fold of "2" and compare it to a k-fold of say "10". The former two models are each trained with a different 50% of the data and the latter ten with 90%. Were the amount of ground truth a limiting factor in model accuracy, then the accuracy would be higher for the 10-fold models, and one could reasonably expect that annotating more ground truth would increase it further.

Ground truth can be limited even further by entering negative numbers into the "k-fold" textbox. "-4" for example would train four models each of which used a different 25% of the data for training (compared to "4" for which each would use 75%). Similarly, "-10" would train 10 each with 10%. Only integers can be used here; "-2" is the same as "2"; and "-1", "0", and "1" are nonsensical. Also keep in mind to not partition your data such that either the training or validation sets have a small number of annotations for any label.

Examining Errors

Mistakes can possibly be corrected if more annotations are made of similar sounds. To find such sounds, cluster the errors made on the ground-truth annotations with sounds detected in your recordings. Then look for localized hot spots of mistakes and make annotations therein.

SongExplorer provides two ways to generate lists of errors, which you'll need to choose between. The Accuracy button does so just for the validation data, while Activations uses the entire ground truth or a randomly sampled subset thereof.

As mentioned earlier, the Accuracy button creates a "predictions/" folder in the Logs Folder containing CSV files itemizing whether the sounds in the validation set were correctly or incorrectly classified. Each CSV file corresponds to a sub-folder within the Ground Truth folder. The file format is similar to SongExplorer's other CSV files, with the difference being that the penultimate column is the prediction and the final one the annotation. To use these predictions, copy these CSV files into their corresponding Ground Truth sub-folders.

$ tail -n 10 trained-classifier1/predictions/round1-mistakes.csv 
PS_20130625111709_ch3.wav,377778,377778,correct,mel-pulse,mel-pulse
PS_20130625111709_ch3.wav,157257,157257,correct,mel-pulse,mel-pulse
PS_20130625111709_ch3.wav,164503,165339,correct,ambient,ambient
PS_20130625111709_ch3.wav,379518,379518,mistaken,ambient,mel-pulse
PS_20130625111709_ch3.wav,377827,377827,correct,mel-pulse,mel-pulse
PS_20130625111709_ch3.wav,378085,378085,correct,mel-pulse,mel-pulse
PS_20130625111709_ch3.wav,379412,379412,mistaken,ambient,mel-pulse
PS_20130625111709_ch3.wav,160474,161353,correct,ambient,ambient
PS_20130625111709_ch3.wav,207780,208572,correct,mel-sine,mel-sine
PS_20130625111709_ch3.wav,157630,157630,correct,mel-pulse,mel-pulse

Similarly, the Activations button creates an "activations.npz" file containing the logits of the output layer (which is just a vector of word probabilities), as well as the correct answer from the ground-truth annotations. To turn these data into a CSV file, use the Mistakes button. In the Ground Truth subfolders, CSV files are created for each WAV file, with an extra column just like above. No need to copy any files here.

Now detect sounds in the ground-truth recordings for which you haven't done so already. Press the Examine Errors wizard and confirm that kinds to use is set to "detected,mistaken", and save the hidden state activations, cluster, and visualize as before. Select mistaken in the kind pull-down menu to look for a localized density. View the snippets in any hot spots to examine the shapes of waveforms that are mis-classified-- the ones whose text label, which is the prediction, does not match the waveform. Then select detected in the kind pull-down menu and manually annotate similar waveforms. In principle they should cluster at the same location.

Testing Densely

The accuracy statistics reported in the confusion matrices described above are limited to the points in time which are annotated. If an annotation withheld to validate upon does not elicit the maximum probability across all output taps at the corresponding label, it is considered an error. Quantifying accuracy in this way is a bit misleading, as when a model is used to make ethograms, a word-specific threshold is applied to the probabilities instead. Moreover, ethograms are made over the entire recording, not just at specific times of interest. To more precisely quantify a model's accuracy then, as it would be used in your experiments, a dense annotation is needed-- one for which all occurrences of any words of interest are annotated.

To quantify an ethogram's accuracy, first select a set of recordings in your validation data that are collectively long enough to capture the variance in your data set but short enough that you are willing to manually label every word in them. Then detect and cluster the sounds in these recordings using the Detect, Activations, Cluster, and Visualize buttons as described earlier. Annotate every occurrence of each word of interest by jumping to the beginning of each recording and panning all the way to the end. Afterwards, manually replace the timestamp in each resulting "annotated-<timestamp>.csv" file with the name of the annotator (e.g. "annotated-<name>.csv"). If you have more than one such dense CSV file per WAV file, retain the timestamp by positioning it before "annotated" (e.g. "<timestamp>-annotated-<name>.csv"). Take your best model to date and make ethograms of these densely annotated recordings using the Classify and Ethogram buttons as before. Finally, use the Congruence button to plot the fraction of false positives and negatives, specifying which files you've densely annotated with Ground Truth and either Validation Files or Test Files (a comma-separated list of .wav files, a text file of .wav filenames, or a folder of .wav files; see Measuring Generalization). Optionally, specify the temporal resolution within which to consider two predictions a hit with convolve. Output are the following charts in the Ground Truth folder and sub-folders therein:

"<sub-folder>/*-disjoint-everyone.csv" contains the intervals in time which SongExplorer and the anotator(s) agreed upon for each WAV file.
"<sub-folder>/*-disjoint-{label,tic}-only<annotator>.csv" contains the intervals which only one of them labeled. There is a separate file for each annotator, with SongExplorer's file name containing the precision-recall ratio used when making the ethograms (e.g. "only1.0pr"). The difference between the "label" and "tic" files is that for the former any overlap in the predicted/annotated intervals is considered a perfect hit, whereas in the latter the two intervals will be broken up into their constituent tics in time if there is a partial overlap. See the source code documentation in "src/congruence.py" for more details.
If there was more than one human annotator (see below) "<sub-folder>/*-disjoint-{tic,label}-not<annotator>.csv" contains the intervals in time which everyone except the indicated annotator agreed upon.
"congruence-{tic,label}-<word>.csv contains the aggregate statistics across all WAV files. Whereas the one row whose first column ends in "pr" shows the congruence for the threshold calculated by Accuracy and the desired precision-recall ratio on just the sparsely annotated points in time, the other rows show how the congruence varies with the threshold.
"congruence-{tic,label}-<word>.*pr[-venn].pdf plots with bars and Venn diagrams the "pr" row of the corresponding CSV file.
"congruence-{tic,label}-<word>.pdf plots the congruence versus threshold data contained in the corresponding CSV file. The vertical line in the left panel labeled "sparse P/R" corresponds to the threshold calculated by Accuracy on just the annotated points in time. "dense P/R" is the threshold at which the "only SongExplorer" and "only <Annotator>" lines cross (or "not SongExplorer" if there are multiple human annotators). These densely calculated thresholds are stored in a new "thresholds-dense-<YYYYMMDDTHHMMSS>.ckpt-*.csv" file in the Logs Folder. Take note of the timestamp and use this file going forward when making new ethograms, as these thresholds most accurately deliver the desired precision-recall ratio. The right panel re-plots the same data by parameterizing precision and recall as a function of threshold. The area under this curve would be 1.0 for a perfect classifier.

If the congruence is not acceptable, iteratively adjust the hyperparameters and/or add new annotations to your training set, train a new model, and make new ethograms and congruence plots until it is.

Once the accuracy is acceptable on validation data, quantify the accuracy on a densely annotated test set. The network should have never been trained or validated on these latter data before; otherwise the resulting accuracy could be erroneously better. Label every word of interest as before, make ethograms with your best model, and plot the congruence with SongExplorer's predictions. Hopefully the accuracy will be okay. If not, and you want to change the hyperparameters or add more training data, then the proper thing to do is to use this test data as training or validation data going forward, and densely annotate a new set of data to test against.

The congruence between multiple human annotators can be quantified using the same procedure. Simply create "annotated-<name>.csv" files for each one. The plots created by Congruence will include lines for the number of sounds labeled by all annotators (including SongExplorer), only each annotator, and not by a given annotator. If the annotators did not label the same portion of each recording, choose "intersection" in portion to specify that the congruence should be calculated only on the portion they have in common-- from the maximum of the minimum annotated time point across annotators to the minimum of the maximum.

Much as one can examine the mistakes of a particular model with respect to sparsely annotated ground truth by clustering with "mistaken" as one of the kinds to use, one can look closely at the errors in congruence between a model and a densely annotated test set by using "everyone|{tic,label}-{only,not}{1.0pr,annotator1,annotator2,...}" as the kinds. The Congruence button generates a bunch of "disjoint.csv" files: "disjoint-everyone.csv" contains the intersection of intervals that SongExplorer and all annotators agreed upon; "disjoint-only*.csv" files contain the intervals which only SongExplorer or one particular annotator labeled; "disjoint-not*.csv" contains those which were labeled by everyone except SongExplorer or a given annotator. Choose one or all of these kinds and then use the Activations, Cluster, and Visualize buttons as before.

When the overall accuracy as judged by, for example, F1 is acceptable, but there is an unacceptable balance between false postives and false negatives, there are two ways to cope. First, the probability waveforms generated by Classify can be adjusted on a word-specific basis to account for known uneven distributions in the prevalence of the words. So for a given interval of time, enter into prevalences a comma-separated list of a priori expected durations for each entry in labels to use (e.g. 6,12,42 seconds for a minute of mel-pulse,mel-sine,ambient respectively); alternatively, the relative probability for each word can be given (e.g. 0.1,0.2,0.7). The probability of relatively rare words will then be decreased in comparison to more common ones, and vice versa, thereby adjusting the precision-to-recall ratio accordingly.

The alternative to adjusting probabilities is to adjust thresholds. While this can be done by changing the P/Rs variable, doing so in this way changes them equally for all words. A word-specific re-balancing of false negatives and false positives can be achieved using thresholds derived from dense annotations. To do so, choose the "thresholds-dense.ckpt-*.csv" file that was created when measuring congruence on the validation data set, instead of the sparse ones created with Accuracy, when making ethograms on the test data set. In effect, this method measures the prevalence of each word, which is possible given a dense annotation, and adjusts the thresholds to achieve the desired precision-to-recall ratio in P/Rs. Note that these dense thresholds CSV files are suffixed with a timestamp, so that they are not overwritten by successive runs of Congruence. Take care to choose the correct one.

Ensemble Models

The procedure used to optimize hyperparameters results in slightly different models with repeated trainings due to the random intialization of weights and sampling of ground truth batches. While initially this might seem undesirable, it affords an opportunity to increase accuracy by averaging across multiple models. Generalization is nominally improved with such combined models due to the reduction in variance.

First create multiple models using either (1) the Train button with # replicates set to be greater than one, (2) the X-Validate button with k-fold greater than one, or even (3) the Omit One button after having annotated multiple recordings. Then use the Ensemble button and select one checkpoint file from each of those models as a comma-separated list. A new subfolder will be created in the Logs Folder with a graph folder therein called "frozen-graph.ensemble.pb". To create a corresponding thresholds file, follow the steps for measuring congruence as described in the previous section (Testing Densely): (1) use this model to classify a densely labeled recording, (2) make an ethogram using the thresholds file of one of the constituent models, and (3) calculate the Congruence. A new thresholds file suffixed with "-dense" will be created. Manually copy this file into the newly created ensemble folder, and use it whenever classifying recordings with this ensemble model.

Transfer Learning

Manually annotation can be a lot of work. Fortunately, the effort spent doing so can be reduced by leveraging someone else's work. Let's say your colleague Alice has trained a model to do a task similar to what you need. You can take her model, keep the first few layers intact with their learned weights, replace the last couple of layers with randomly initialized ones of your own, and then iteratively train and annotate as described above. The features in the early layers will already be quite rich, and so the new latter layers will not need as much ground truth data to learn your task. Moreover, if your colleagues Bob and Carol also have similar trained models, you can combine all three in a similar fashion.

SongExplorer comes with an architecture plugin (see Customizing with Plug-ins for details on how plugins work) called "ensemble-transfer" that makes all this easy. Modify the architecture_plugin variable in your "configuration.py" file to be "ensemble-transfer". Then in the SongExplorer GUI specify (1) the checkpoint(s) of the pretrained model(s) you want to use, (2) whether you want to update the weights of the pretrained model when you train with your data (or just the new layers), (3) how many of the layers of the pretrained model(s) you want to use, (4) how many new convolutional layers you want to add (for each layer: kernel time size x kernel frequency size x num. features; e.g. "5x5x32,10x10x64"), (5) how many new dense layers you want to add (for each layer: num. units; e.g. "128,32,8"), and (6) the dropout rate (e.g. 50). Then iteratively train and fix mistakes as before.

Note that the pretrained models do not necessarily have to use the sampling rate-- the "ensemble-transfer" plugin will automatically insert a resampling layer if necessary.

Autoencoding

There is an unsupervised variation of transfer learning that is particularly useful if you have a lot of unlabelled data. You start by training a model whose output layer is identical in shape to its input layer and inbetween there is a layer with much fewer units. The task is to reconstruct the input at the output despite this bottleneck, thereby learning a compact representation of the domain. One of the hidden layers, typically the smallest one, is then used as the input to a second model which is trained in a supervised manner with the few labels you have. Typically this second model is architecturally very simple, maybe consisting of just a single layer.

To use this workflow in SongExplorer, manually create an "autoencoded.csv" file for each recording which has a single row whose start and stop tics correspond to the beginning and end of the file. Something like this:

PS_20130625111709_ch3.wav,1,2500,autoencoded,all

Set the architecture_plugin to "autoencoder", and devise an architecture whose first few layers are similar to that which you would normally use for a supervised task. These will then be automatically mirrored.

Choose "autoencoder" for the "loss" pull-down menu in the GUI. Train and search the hyperparameter space as usual. The "train-validation-loss.pdf" plots will not show the precision and recall curves, and rather add the validation loss to compare with the train loss. Similarly the precision and recall scatter plots are not drawn for compare, and instead the validation loss curves are overlayed and the size of the bottleneck is shown.

classify a withheld recording to see how faithful the reconstruction is. If it looks reasonable, change the architecture_plugin to "ensemble-transfer" and proceed as described in Transfer Learning.

Discovering Novel Sounds

After amassing a sizeable amount of ground truth one might wonder whether one has manually annotated all of the types of words that exist in the recordings. One way to check for any missed types is to look for hot spots in the clusters of detected sounds that have no corresponding annotations. Annotating known types in these spots should improve generalization too.

First, use the Detect button to threshold the recordings that you want to search for novel sounds. Save their hidden state activations, along with those of the manually annotated sounds, using the Activations button by setting the label types to "annotated,detected". Set equalize ratio to a small integer as well, so that words with few samples are not obscured by those with many. Cluster and visualize as before. Now rapidly and alternately switch between annotated and detected in the kind pull-down menu to find any differences in the density distributions. Click on any new hot spots you find in the detected clusters, and annotate sounds which are labeled as detected but not annotated. Create new word types as necessary.

Overlapped Classes

So far we have assumed that songs of interest do not overlap, as is usually the case in a laboratory setting with just a single or small number of animals. In this case, the output taps of the neural network are considered mutually exclusive and a soft-max function is used to ensure that the probabilities across classes add to one at any given point in time.

This assumption quickly breaks down in field recordings, however, where multiple individuals from multiple species may be present. In this case, we need to design the network's outputs such that each of them can be reinterpreted as indicating whether a song is present or not, and to do so independently of each other. Specifically, the soft-max across all outputs is replaced with an individual sigmoid function for each.

To train a network in this fashion, a second set of labels must be used to indicate the absence of a class. So, for example, "mel-sine" from the tutorial above would be paired with "not_mel-sine", and similarly for "mel-pulse" and "not_mel-pulse, etc. (but not "not_ambient"!). These "not_" annotations don't necessarily have to be intervals in time during which no sound is present (i.e. are ambient), but rather just no song of that class is present. In fact, it's best to make "not_" annotations which also include sounds, and may even contain song from another class.

Once you have annotated in this manner, select "overlapped" from the "loss" pull-down menu. Then enter the classes in labels to use as before, but do not enter the "not_" labels there-- rather, songexplorer will automatically use the "not_" annotations in the groundtruth folder corresponding to those classes in "labels to use" when "overlapped" is chosen. Then train a model and make predictions as before. You should then find that the probability waveforms do not necessarily add to one, and that the ethograms may be overlapped.

For maximum flexibility, in the case that one of your class names naturally starts with "not_", the prefix used to indicate the absence of a class can be specified in your configuration.py file. See the variable named "overlapped_prefix", which defaults to "not_".

Unsupervised Methods

Until now we have only considered the workflow to manually annotate individual sounds. Some data sets and experiments are amendable to automatically labelling them en masse however. Say, for example, it is known for sure that there is only a single species audible in each recording and all that is needed is to identify the species. In this and other similar cases a sequence of actions already individually described above can be used. First use the Detect button to find sounds in each recording. Then manually edit the resulting CSV files to change each "time" and "frequency" entry to the name of the species. Finally use the Train button to create a species detector by setting kinds to use to "detected" and labels to use to the species names. You can now use the Accuracy, Freeze, Classify, and Ethogram buttons as before to make predictions on new recordings. How well this works is subject to the signal-to-noise ratio of your data of course; you might need to carefully tune the parameters used when detecting sounds.

A simple model like this is useful for more that just classifying species. It can also be used to look for differences in vocalizations in closely related species, genetic mutants of the same species, or even individuals within the same species. To do so, use the species, mutant, or individuals name as the label in the CSV files when training the model. Then cluster the hidden state activations of the already detected sounds using this same model with the Activations, Cluster, and Visualize buttons as before. Any non-overlapping clumps are evidence of unique vocalizations.

Finally it should be noted that large amounts of ambient and "other" annotations can be in some cases be automatically labeled. If you can devise a way to position your microphone in a place and time for which no natural sounds are made but for which the "room tone" is otherwise the same, then the entire recording can be considered ambient. Similarly, even if there are natural sounds present, so long as none of them are from any species of interest, then the Detect button can be used to pick out sounds that can all be considered "other".

Scripting Automation

For some tasks it may be easier to write code instead of use the GUI-- tasks which require many tedious mouse clicks, for example, or simpler ones that must be performed repeatedly. To facilitate coding your analysis, SongExplorer is structured such that each action button (Detect, Misses, Activations, etc.) is backed by a Python script. At the top of each script is documentation showing how to call it. Here, for example, is the interface for Detect:

$ head -n 13 <path-to-unzipped-executable>/songexplorer/bin/songexplorer/src/time-freq-threshold.py 
#!/usr/bin/env python3

# threshold an audio recording in both the time and frequency spaces

# e.g.
# time-freq-threshold.py \
#     --filename=`pwd`/groundtruth-data/round2/20161207T102314_ch1_p1.wav \
#     --parameters={"time_sigma":"9,4", "time_smooth_ms":"6.4", "frequency_n_ms":"25.6", "frequency_nw":"4", "frequency_p":"0.1,1.0", "frequency_smooth_ms":"25.6", "time_sigma_robust":"median"} \
#     --audio_tic_rate=2500 \
#     --audio_nchannels=1 \
#     --audio_read_plugin=load-wav \
#     --audio_read_plugin_kwargs={}

The following Bash code directly calls this script to make predictions on a set of recordings in different folders:

$ wavfiles=(
           groundtruth-data/round1/PS_20130625111709_ch3.wav
           groundtruth-data/round2/20161207T102314_ch1.wav
           groundtruth-data/round3/Antigua_20110313095210_ch26.wav
           )

$ for wavfile in ${wavfiles[@]} ; do
      time-freq-threshold.py \
          --filename=$wavfile \
          --parameters={"time_sigma":"9,4", "time_smooth_ms":"6.4", \
                        "frequency_n_ms":"25.6", "frequency_nw":"4", \
                        "frequency_p":"0.1,1.0", "frequency_smooth_ms":"25.6", \
                        "time_sigma_robust":"median"} \
          --audio_tic_rate=2500 \
          --audio_nchannels=1 \
          --audio_read_plugin=load-wav \
          --audio_read_plugin_kwargs={}
  done

The above workflow could also easily be performed in Julia, Python, Matlab, or any other language that can execute shell commands.

Alternatively, one can also write a Python script which invokes SongExplorer's GUI interface to programmatically fill text boxes with values and to push action buttons:

import sys
import os

# load the GUI
sys.path.append(os.path.join(<path-to-unzipped-executable>,
                             "songexplorer", "bin", "songexplorer", "src", "gui"))
import model as M
import view as V
import controller as C

# start the GUI
M.init("configuration.py")
V.init(None)
C.init(None)

# start the job scheduler
run(["hstart",
      str(local_ncpu_cores)+','+str(local_ngpu_cards)+','+str(local_ngigabytes_memory)])

# set the needed textbox variables
V.detect_parameters["time_sigma"].value = "9,4"
V.detect_parameters["time_smooth_ms"].value = "6.4"
V.detect_parameters["frequency_n_ms"].value = "25.6"
V.detect_parameters["frequency_nw"].value = "4"
V.detect_parameters["frequency_p"].value = "0.1,1.0"
V.detect_parameters["frequency_smooth_ms"].value = "25.6"
V.detect_parameters["time_sigma_robust"].value = "median"

# repeatedly push the Detect button
wavpaths_noext = [
                 "groundtruth-data/round1/PS_20130625111709_ch3",
                 "groundtruth-data/round2/20161207T102314_ch1",
                 "groundtruth-data/round3/Antigua_20110313095210_ch26",
                 ]
for wavpath_noext in wavepaths_noext:
    V.wavtfcsvfiles.value = wavpath_noext+".wav"
    C.detect_actuate()

# stop the job scheduler
run(["hstop"], stdout=PIPE, stderr=STDOUT)

For more details see the system tests in /songexplorer/bin/songexplorer/test/tutorial.{sh,py}. These two files implement, as Bash and Python scripts respectively, the entire workflow presented in this Tutorial, from Detecting Sounds all the way to Testing Densely.

Training on Video

SongExplorer was conceived to analyze one-dimensional audio recordings. However, in addition to being able to view accompanying 3D video recordings as described in Manually Annotating, one can also train a model on them as well, either in conjuction with audio recordings or alone.

The default plugin to load video data is "src/load-avi-mp4-mov.py", and a blank template is "src/video-read-plugin.py". These work similarly to the corresponding plugins to load audio recordings.

See "src/video.py" for a network architecture plugin that inputs only video, and "src/ensemble-concat-dense.py" for an architecture plugin which combines a (possibly pretrained) audio-only model and a (possibly pretrained) video-only model with a simple top model.

Customizing with Plug-ins

Loading Data

As described above the default file format for audio recordings is WAV files. Should your data be in a different format, one option is to convert it all. Alternatively, if you are fluent in python, you can write a script which tells SongExplorer how to load the raw data. This script should define a function called audio_read which inputs the full path to the recording as well as an interval of time and possibly some keyword arguments, and returns the sampling rate and the slice of the data during that interval. To see how this works, take a look at src/load-wav.py, which is the default plugin, and src/audio-read-plugin.py which is a blank template.

A further advantage of loading data in a plugin script is that you can add custom signal pre-preprocessing. Say for example there is artifactual noise in a particular frequency band. You can eliminate that before SongExplorer ever sees the data by simply adding a filter to the plugin. One particular use case is ultrasonic vocalizations, which are frequently contaminated by low frequency audible noise. SongExplorer comes with a plugin, src/highpass-filter.py, which uses a butterworth filter with a customizable cutoff frequency to attenuate that noise.

Video loading is also done with a plugin. The default is src/load-avi-mp4-mov.py and a blank template is in src/video-read-plugin.py.

To use an alternative plugin, change the "audio_read_plugin" variable in "configuration.py". It should be a python 2-tuple, with the first element being the full path to the script, without the ".py" extension, and the second being a dictionary of keyword arguments. The specific format for each plugin is documented in a comment at the top of each python script.

Video Filenames

By default, SongExplorer expects video files to have the same basename as the corresponding audio file, and the extension to be one of AVI, MP4, or MOV. If this is not the case, one can provide a python function which inputs a directory and a WAV file and outputs the name of the video file to load. The name and location of the python file containing this function is specified, without the ".py" extension, as the "video_findfile_plugin" parameter in "configuration.py". For examples, see "src/same-basename.py" (the default) and "src/maybe-1sec-off.py".

Event Detection

By default the Detect button thresholds in the time and frequency domains to find sounds of interest. See the source code in "src/time-freq-threshold.py" for exactly how this works. Should that not suit your needs, you can supply your own code instead. Simply put in a python file a list called detect_parameters that specifies the hyperparameters, a function called detect_labels which returns the strings used to annotate the sounds, and a script which uses those parameters to generate a "detected.csv" given a WAV file. Then change the "detect_plugin" variable in your "configuration.py" file to point to the full path of this python file, without the ".py" extension. See the minimal example in "src/detect-plugin.py" for a template.

Double-Click Annotations

New annotations can be layed down by double-clicking a snippet, double-clicking on an event in the upper half of the context window, clicking and horizontally dragging in the lower half of the context window, or double-clicking in a blank portion of the lower half of context window. The default behavior for the latter method results in a point annotation at just a single sample tic.

While it is best to be as temporally precise as possible when annotating, it can be quite slow to position the cursor exactly at an event. Moreover, unless the event really has no temporal extent, it is better to use a range annotation, as SongExplorer will automatically augment these annotations by randomly choosing a specific point in time within them each time they are chosen for a batch of training examples.

To facilitate temporally-precise range annotations with a double-click gesture, SongExplorer has a hook in the callback which you can supply with python code to customize the behavior. The python file must contain a list called doubleclick_parameters which defines the required hyperparameters, and a function called doubleclick_annotation which inputs a point in time and outputs a range. See "src/snap-to.py" for a plugin which searches for a nearby peak in the waveform and lays down a range annotation of a specified width. The default double-click plugin is "src/point.py" and a template is in "src/doubleclick-plugin.py".

Network Architecture

The default network architecture is a set of layered convolutions, the depth and width of which can be configured as described above. Should this not prove flexible enough, SongExplorer is designed with a means to supply your own TensorFlow code that implements a whiz bang architecture of any arbitrary design. See the minimal example in "src/architecture-plugin.py" for a template of how this works. In brief, two objects must be supplied in a python file: (1) a list named model_parameters which defines the variable names, titles, and default values, etc. to appear in the GUI, and (2) a function create_model which builds and returns the network graph. Specify as the architecture_plugin in "configuration.py" the full path to this file, without the ".py" extension. The buttons immediately above the configuration textbox in the GUI will change to reflect the different hyperparameters used by this architecture. All the workflows described above (detecting sounds, making predicions, fixing mistakes, etc) can be used with this custom network in an identical manner. The default convolutional architecture is itself written as a plug-in, and can be found in "src/convolutional.py".

Clustering Algorithm

The method used to reduce the dimensionality of the activations for visualization is also a plugin. By default, the UMAP algorithm is used, but also included are plugins for t-SNE (van der Maaten and Hinton (2008)) and PCA. To use these alternatives change "cluster_plugin" in "configuration.py" to "tSNE" or "PCA", respectively. To create your own plugin, write a script which defines a list called cluster_parameters, inputs "activations.npz" and outputs "cluster.npz". See "src/cluster-plugin.py" for a template.

Troubleshooting

Sometimes using control-C to quit out of SongExplorer does not work. In this case, kill it with ps auxc | grep -E '(songexplorer|bokeh)' and then kill -9 <pid>. Errant jobs can be killed similarly.
Full paths on MS Windows are limited to 260 characters
If Songexplorer doesn't start as usual, try deleting "songexplorer.state.yml" and trying again
If jobs launched with the red DoIt! button seem to hang, check if the computer is busy doing something with top (or Activity Monitor on MacOS and Task Monitor on MS Windows). If it is not, open a terminal or shell and check SongExplorer's queue of jobs using songexplorer/bin/hjobs. If necessary, use hkill to remove a job from the queue, and hstop to shut down the queue.

Frequently Asked Questions

The WAV,CSV Files text box, being plural, can contain multiple comma-separated filenames. Select multiple files in the File Browser using shift/command-click as you would in most other file browsers.

Reporting Problems

The code is hosted on github. Please file an issue there for all bug reports and feature requests. Pull requests are also welcomed! For major changes it is best to file an issue first so we can discuss implementation details. Please work with us to improve SongExplorer instead instead of forking your own version.

Development

Conda is the preferred development environment. The Singularity and Docker files provided use conda internally.

Conda

Platform-specific conda installation instructions can be found at Conda. On Macs you can also use Homebrew to install conda. On MS Windows, miniforge by default uses a command prompt; execute conda init powershell to used conda in PowerShell.

To build locally, first download the source code and install the conda build command. These only need to be done once:

$ git clone https://github.com/JaneliaSciComp/SongExplorer
$ conda install conda-build

Then build:

$ conda build <path-to-songexplorer-repo>/install/conda/songexplorer -c conda-forge -c nvidia

To install directly from this local build:

$ conda create --name songexplorer
$ conda install -n songexplorer --use-local songexplorer -c conda-forge -c nvidia

Pay attention to the notice at the end demarcated with "*** IMPORTANT !!! ***". Follow the directions therein to install platform-specific dependencies which are not in conda-forge.

If you have trouble using the GPU on Ubuntu 22.04, you might need to move a library, set XLA_FLAGS in your environment, and install cuda-nvcc:

$ conda activate songexplorer
$ mkdir -p $CONDA_PREFIX/lib/nvvm/libdevice/
$ cp -p $CONDA_PREFIX/lib/libdevice.10.bc $CONDA_PREFIX/lib/nvvm/libdevice/
$ echo 'export XLA_FLAGS=--xla_gpu_cuda_data_dir=$CONDA_PREFIX/lib' >> $CONDA_PREFIX/etc/conda/activate.d/env_vars.sh
$ conda install -c nvidia cuda-nvcc

To upload to the Janelia forge:

$ conda activate base
$ conda install anaconda-client
$ anaconda login
$ anaconda upload -u janelia $CONDA_PREFIX/conda-bld/<architecture>/songexplorer-<version>-0.tar.bz2

Subsequently you can install directly from the Janelia forge, instead of your local build:

$ conda create --name songexplorer
$ conda install songexplorer -n songexplorer -c janelia -c nvidia -c conda-forge

To upgrade to the latest version, first get the new version and delete the local build, and then execute the above commands again:

$ git -C <path-to-songexplorer-repo> pull
$ conda env remove --name songexplorer
$ conda build purge-all

To update the conda recipe, tag a new version and make a github release, then update "meta.yaml" with the new version number and new hash for the tar.gz asset:

$ git tag v<version>
$ git push --tags

$ openssl sha256 <github-tar-gz-file>

To upload a tarball to Github, compress the conda environment and drag and drop it into the assets section of the releases page:

$ cd $CONDA_PREFIX/envs
$ tar czf songexplorer-<version>-<architecture>.tar.gz songexplorer
$ cat songexplorer-<version>-<architecture>.tar.gz | split --bytes=2GB - songexplorer-<version>-<architecture>.tar.gz.

After downloading, some users will need to re-install some pip dependencies (e.g. tensorflow-metal on MacOS) as they are not in general relocatable:

$ pip3 install --target <path-to-unzipped-tarball>/songexplorer/lib/python3.10/site-packages tensorflow-metal

To make changes to the code, do so in the git repository while using the dependent packages in the conda environment:

$ conda activate songexplorer
$ echo PATH=<path-to-git-repo>/src:$PATH >> $CONDA_PREFIX/etc/conda/activate.d/env_vars.sh
$ echo PATH=<path-to-git-repo>/test:$PATH >> $CONDA_PREFIX/etc/conda/activate.d/env_vars.sh
$ conda activate songexplorer

Or, skip activating a conda environment and depend on the packages in the tarball instead:

$ echo PATH=<path-to-git-repo>/src:$PATH >> ~/.bashrc
$ echo PATH=<path-to-git-repo>/test:$PATH >> ~/.bashrc
$ echo PATH=<path-to-extracted-tarball>/bin:$PATH >> ~/.bashrc

Currently, songexplorer hangs for large models on Windows. This, despite updating to the latest version of WSL:

$ wsl --status
$ wsl --update
$ wsl --shutdown
$ wsl --status

Singularity

To build an image, change to a local (i.e. not NFS mounted; e.g. /opt/users) directory and:

$ git clone https://github.com/JaneliaSciComp/SongExplorer.git
$ rm -rf songexplorer/.git
$ sudo singularity build -s [-B /opt:/mnt] [--no-cleanup] songexplorer.img songexplorer/install/singularity.def

To confirm that the image works:

$ singularity run --nv songexplorer.img
>>> import tensorflow as tf
>>> msg = tf.constant('Hello, TensorFlow!')
>>> tf.print(msg)

Compress the image into a single file:

$ sudo singularity build [--tmpdir <>] songexplorer.sif songexplorer.img

Next create an access token at cloud.sylabs.io and login using:

$ singularity remote login SylabsCloud

Then push the image to the cloud:

$ singularity sign songexplorer.sif
$ singularity push songexplorer.sif library://bjarthur/janelia/songexplorer[:<version>]

To download the image from the cloud. You can either go to SongExplorer's cloud.sylabs.io page and click the Download button, or equivalently use the command line:

$ singularity pull library://bjarthur/janelia/songexplorer:latest
INFO:    Container is signed
Data integrity checked, authentic and signed by:
  ben arthur (songexplorer) <[email protected]>, Fingerprint XXABCXXX

Put these definitions in your .bashrc file:

export SONGEXPLORER_BIN="singularity exec [--nv] [-B <disk-drive>] \
    [--vm-cpu] [--vm-ram] <path-to-songexplorer_latest.sif>"
alias songexplorer="$SONGEXPLORER_BIN songexplorer <path-to-configuration.py> 5006"

To use a copy of the SongExplorer source code outside of the container, set SINGULARITYENV_PREPEND_PATH to the full path to SongExplorer's src directory in your shell environment. source_path in "configuration.py" must be set similarly if using a remote workstation or a cluster.

Docker

To start docker on Linux and set permissions:

$ service docker start
$ setfacl -m user:$USER:rw /var/run/docker.sock

To build a docker image and push it to docker hub:

$ cd songexplorer
$ docker build --file=install/dockerfile --tag=bjarthur/songexplorer[:<tag>] \
      [--no-cache=true] .
$ [docker tag <image-id> bjarthur/songexplorer:<tag>]  % get image-id from `docker image ls`
$ docker login
$ docker push bjarthur/songexplorer[:<tag>]

To remove a tag from docker hub:

$ docker run --rm lumir/remove-dockerhub-tag --user bjarthur \
      --password <password> bjarthur/songexplorer:<tag>

To pull an image from docker hub:

$ docker pull bjarthur/songexplorer
Using default tag: latest
latest: Pulling from bjarthur/songexplorer
Digest: sha256:466674507a10ae118219d83f8d0a3217ed31e4763209da96dddb03994cc26420
Status: Image is up to date for bjarthur/songexplorer:latest

Put these definitions in your .bashrc file:

export SONGEXPLORER_BIN="docker run \
    [-v <disk-drive>] [-u <userid>] [-w <working-directory] \
    bjarthur/songexplorer"
alias songexplorer="docker run \
    [-v <disk-drive>] [-u <userid>] [-w <working-directory] \
    -e SONGEXPLORER_BIN -h=`hostname` -p 5006:5006 \
    bjarthur/songexplorer songexplorer <path-to-configuration.py> 5006"

Add to these definitions any directories you want to access using the -v flag. You might also need to use the -u flag to specify your username or userid. Optionally specify the current working directory with the -w flag.

To quit out of SongExplorer you might need to open another terminal window and issue the stop command:

$ docker ps
CONTAINER ID IMAGE             COMMAND               CREATED       STATUS ...
6a26ad9d005e bjarthur/songexplorer "detect.sh /src/p..." 3 seconds ago Up 2 seconds ...

$ docker stop 6a26ad9d005e

To make this easy, put this short cut in your .bashrc file:

alias dockerkill='docker stop $(docker ps --latest --format "{{.ID}}")'

On Windows docker runs within a virtual machine that is configured by default to only use half the available CPU cores and half of the memory. This configuration can be changed in the Preferences window. Note that even when SongExplorer is idle these resources will not be available to other programs, including the operating system.

To monitor resource usage:

$ docker stats

To run a container interactively add "-i --tty".

System Tests

SongExplorer comes with a comprehensive set of tests to facilitate easy validation that everything works both after you've first installed it as well as after any changes have been made to the code. The tests exercise both the Python GUI as well as the Linux Bash interfaces. To run them, simply execute "runtests":

$ <path-to-unzipped-executable>/songexplorer/bin/songexplorer/test/runtests

Name		Name	Last commit message	Last commit date
Latest commit History 579 Commits
app		app
data		data
install		install
src		src
test		test
LICENSE-TF.txt		LICENSE-TF.txt
LICENSE.txt		LICENSE.txt
README.md		README.md
VERSION.txt		VERSION.txt
configuration.py		configuration.py

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JaneliaSciComp/SongExplorer

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