News - Justin Salamon

Sox vs Rubberband for Audio Pitch Shifting and Time Stretching

30/4/2020

This page compares the sound quality for audio pitch shifting and audio time stretching between Sox and Rubberband on different types of audio inputs.

I recently compared the two to decide which one to use in my Scaper soundscape synthesis and augmentation library, and figured I'd share what I found here in case anyone finds it helpful.

Sox and Rubberband are two excellent open-source command-line tools for audio processing. Both have python wrappers too: pysox and pyrubberband.

Both sox and rubberband provide optional arguments that allow you to fine tune the shifting/stretching algorithm for the specific audio content being processed. In my very quick and dirty (and non-comprehensive) exploration, I found one setting for sox and one setting for rubberband that generally gave the best sounding results (to my ears), so I used the same setup for all comparisons below.

â€‹In all the audio examples below, the following commands were used:

Pitch shifting:

sox infile.wav outfile.wav pitch 100
rubberband --pitch 1 infile.wav outfile.wav -c 6

Time stretching:

sox infile.wav outfile.wav tempo -s 0.833
rubberband --time 1.2 infile.wav outfile.wav -c 6

I strongly recommend listening to the examples below with good headphones, since the differences are sometimes quite subtle (but definitely noticeable with a good pair of cans).

Speech

Original

Pitch shift: Sox

Pitch shift: Rubberband

Time stretch: Sox

Time stretch: Rubberband

Engine

Original

Pitch shift: Sox

Pitch shift: Rubberband

Time stretch: Sox

Time stretch: Rubberband

Music: male voice

Original

Pitch shift: Sox

Pitch shift: Rubberband

Time stretch: Sox

Time stretch: Rubberband

â€‹Music: female voice

Original

Pitch shift: Sox

Pitch shift: Rubberband

Time stretch: Sox

Time stretch: Rubberband

So... which one's better? Like most things in life, it depends. It depends on your target application and what matters most in that context, it depends whether you're only doing pitch shifting or time stretching or both, it depends on your audio content, the parameters you choose...

For my application I have a relatively clear winner, but I won't bias you with my opinion ;)

Compute Deep Image & Audio Embeddings with OpenL3

27/1/2020

OpenL3 computes deep image & audio embeddings using a self-supervised L3-Net model and can be installed with a simple "pip install openl3" !

Back in May 2019 we announced the release of OpenL3, an open-source python library for computing deep audio embeddings using an improved L3-Net architecture trained on AudioSet. Today we're happy to announce the release of OpenL3 v0.3.0 which can also compute deep image embeddings!

Installing OpenL3 is easy (requires TensorFlow):

pip install openl3

And computing image embeddings is as easy as:

image = imread('/path/to/file.png')
emb = openl3.get_image_embedding(image, embedding_size=512)

Computing audio embeddings is equally simple:

audio, sr = soundfile.read('/path/to/file.wav')
embedding, timestamps = openl3.get_audio_embedding(audio, sr)

You can even process video files directly to obtain both image and audio embeddings:

openl3.process_video_file(video_filepath, output_dir='/path/to/output/folder')

Full instructions and all available options are described in the OpenL3 Tutorial. There's also an OpenL3 command line interface (CLI) if you want to script outside of python.

Full details about the embedding models and how they were trained can be found in:

Look, Listen and Learn More: Design Choices for Deep Audio Embeddings
J. Cramer, H.-H. Wu, J. Salamon, and J. P. Bello.
IEEE Int. Conf. on Acoustics, Speech and Signal Proc. (ICASSP), pp 3852-3856, Brighton, UK, May 2019.
[IEEE][PDF][BibTeX][Copyright]

We hope the machine learning community, including both computer vision and machine listening researchers, find OpenL3 useful in their work!

Adobe Audio Research Interns Submit Papers to ICASSP, CVPR, ICLR, CHI, IEEE VR, INTERSPEECH, ISMIR

24/1/2020

This past summer we had the pleasure of hosting 14 brilliant students (most of them pursuing their PhD but also Master's and Bachelor's) for audio research internships in San Francisco and Seattle. We worked together on a wide range of audio-related topics including speech processing, music, video, animation, spatial audio, VR, DAFX... the works! The projects also covered a range of disciplines including machine learning (including a healthy dose of deep learning), signal processing and human computer interaction; and a range of problems within these disciplines such as self-supervision and representation learning, metric learning, classification, transformation and generation (synthesis).

As a mentor, it was an incredible experience to guide, collaborate, and learn from this diverse group of people coming from a variety of disciplines and universities in 5 different countries. Between interns and mentors we spanned 11 different countries of origin, making it a truly international group! I'm also delighted to say a large proportion of internship projects have resulted in paper submissions to top-tier venues including ICASSP, CVPR, ICLR, CHI and IEEE VR, with upcoming submissions to INTERSPEECH and ISMIR in preparation!

The 2019 audio research interns were:

Emma Frid, KTH Royal Institute of Technology
Nathan Keil, Rensselaer Polytechnic Institute
Jongpil Lee, Korea Advanced Institute of Science and Technology
Stylianos Mimilakis, Technical University of Ilmenau
Max Morrison, Northwestern University
Kaizhi Qian, University of Illinois at Urbana-Champaign
Lucas Rencker, University of Surrey
Oona Risse-Adams, University of California, Santa Cruz
Jiaqi Su, Princeton University
Zhenyu Tang, University of Maryland-College Park
Yapeng Tian, University of Rochester
Yu Wang, New York University
Karren Yang, Massachusetts Institute of Technology
Yang Zhou, University of Massachusetts Amherst

I look forward to keeping in touch with everyone and hope we get to collaborate again in the future!

The 2019 San Francisco audio research mentors and interns (Seattle team we love you!)

Elected to the IEEE Audio and Acoustic Signal Processing Technical Committee

14/1/2020

I'm happy to report I've been elected to the IEEE Audio and Acoustic Signal Processing Technical Committee.

The AASP TC's mission is to support, nourish and lead scientific and technological development in all areas of audio and acoustic signal processing. These areas are currently seeing increased levels of interest and significant growth providing a fertile ground for a broad range of specific and interdisciplinary research and development. Ranging from array processing for microphones and loudspeakers to music genre classification, from psychoacoustics to machine learning, from consumer electronics devices to blue-sky research, this remit encompasses countless technical challenges and many hot topics. The TC numbers some 30 appointed volunteer members drawn roughly equally from leading academic and industrial organizations around the world, unified by the common aim to offer their expertise in the service of the scientific community.

Looking forward to doing my bit for this excellent scientific community!

SONYC-UST: A MULTILABEL DATASET FROM AN URBAN ACOUSTIC SENSOR NETWORK

5/1/2020

SONYC Urban Sound Tagging (SONYC-UST) is a dataset for the development and evaluation of machine listening systems for realworld urban noise monitoring. It consists of 3068 audio recordings from the "Sounds of New York City" (SONYC) acoustic sensor network:

Via the Zooniverse citizen science platform, volunteers tagged the presence of 23 fine-grained classes that were chosen in consultation with the New York City Department of Environmental Protection. These 23 fine-grained classes can be grouped into eight coarse-grained classes:

The SONC-UST taxonomy (click to enlarge)

For more details please see:

SONYC Urban Sound Tagging (SONYC-UST): A Multilabel Dataset from an Urban Acoustic Sensor Network
M. Cartwright, A. E. Mendez Mendez, J. Cramer, V. Lostanlen, G. Dove, H.-H. Wu, J. Salamon, O. Nov, and J.P. Bello
Detection and Classification of Acoustic Scenes and Events 2019 Workshop (DCASE2019), pages 35-39, New York University, NY, USA, Oct. 2019.

Download SONYC-UST: https://doi.org/10.5281/zenodo.3338310

TriCycle: Audio Representation Learning from Sensor Network Data Using Self-Supervision

4/11/2019

Self-supervised representation learning with deep neural networks is a powerful tool for machine learning tasks with limited labeled data but extensive unlabeled data. To learn representations, self- supervised models are typically trained on a pretext task to predict structure in the data (e.g. audio-visual correspondence, short-term temporal sequence, word sequence) that is indicative of higher-level concepts relevant to a target, downstream task. Sensor networks are promising yet unexplored sources of data for self-supervised learning - they collect large amounts of unlabeled yet timestamped data over extended periods of time and typically exhibit long-term temporal structure (e.g., over hours, months, years) not observable at the short time scales previously explored in self-supervised learning (e.g., seconds). This structure can be present even in single-modal data and therefore could be exploited for self-supervision in many types of sensor networks. In this work, we present a model for learning audio representations by predicting the long-term, cyclic temporal structure in audio data collected from an urban acoustic sensor network. We then demonstrate the utility of the learned audio representation in an urban sound event detection task with limited labeled data.

Read the full paper here:

TriCycle: Audio Representation Learning from Sensor Network Data Using Self-Supervision
M. Cartwright, J. Cramer, J. Salamon, and J.P. Bello
In IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA), New Paltz, NY, USA, Oct. 2019.
[IEEE][PDF][BibTeX][Copyright]

Robust Sound Event Detection in Bioacoustic Sensor Networks

24/10/2019

The innovation: we present a context-adaptive deep network that uses an auxiliary sub-network to model the background environment to improve inference-time robustness to changing environments.

The results: The proposed model produces state-of-the results on flight call detection that are robust to environmental changes across time and space.

The surprise: Interestingly, we find that while context adaptation alone doesn't help significantly, and applying PCEN pre-processing doesn't help much either, applying both combined leads to dramatic gains.

The tech: We release BirdVoxDetect, an open-source tool for automatically detecting avian flight calls in continuous audio recordings: https://github.com/BirdVox/birdvoxdetect

Installing BirdVoxDetect (assuming Python is installed) is as easy as calling : pip install birdvoxdetect

Full paper:
Robust Sound Event Detection in Bioacoustic Sensor Networks
V. Lostanlen, J. Salamon, A. Farnsworth, S. Kelling, and J.P. Bello
PLoS ONE 14(10): e0214168, 2019. DOI: https://doi.org/10.1371/journal.pone.0214168
[PLoS ONE][PDF][BibTeX]

Model block diagram:

Abstract:
Bioacoustic sensors, sometimes known as autonomous recording units (ARUs), can record sounds of wildlife over long periods of time in scalable and minimally invasive ways. Deriving per-species abundance estimates from these sensors requires detection, classification, and quantification of animal vocalizations as individual acoustic events. Yet, variability in ambient noise, both over time and across sensors, hinders the reliability of current automated systems for sound event detection (SED), such as convolutional neural networks (CNN) in the time-frequency domain. In this article, we develop, benchmark, and combine several machine listening techniques to improve the generalizability of SED models across heterogeneous acoustic environments. As a case study, we consider the problem of detecting avian flight calls from a ten-hour recording of nocturnal bird migration, recorded by a network of six ARUs in the presence of heterogeneous background noise. Starting from a CNN yielding state-of the-art accuracy on this task, we introduce two noise adaptation techniques, respectively integrating short-term (60 ms) and long-term (30 min) context. First, we apply per-channel energy normalization (PCEN) in the time-frequency domain, which applies short-term automatic gain control to every subband in the mel-frequency spectrogram. Secondly, we replace the last dense layer in the network by a context-adaptive neural network (CA-NN) layer, i.e. an affine layer whose weights are dynamically adapted at prediction time by an auxiliary network taking long-term summary statistics of spectrotemporal features as input. We show that PCEN reduces temporal overfitting across dawn vs. dusk audio clips whereas context adaptation on PCEN-based summary statistics reduces spatial overfitting across sensor locations. Moreover, combining them yields state-of-the-art results that are unmatched by artificial data augmentation alone. We release a pre-trained version of our best performing system under the name of BirdVoxDetect, a ready-to-use detector of avian flight calls in field recordings.

Build a Web-Based Ukulele Tuner using CREPE

7/10/2019

The YouTube coding channel The Coding Train just published its latest Coding Challenge: "Ukulele Tuner with Machine Learning Pitch Detection Model", where they use our CREPE model to build a web-based ukulele tuner! Awesome!

They use CREPE via the ml5.js library which offers a variety of ML algorithms for the web. It was a delightful surprise to discover that CREPE is being used to power the pitchDetection function.

You can watch the full video here:

What's Broken in Music Informatics Research? Three Uncomfortable Statements

20/6/2019

Companion website for my invited talk at the Machine Learning for Music Discovery workshop at ICML 2019: "What's Broken in Music Informatics Research? Three Uncomfortable Statements".

VIDEO:

PAPER:

What's Broken in Music Informatics Research? Three Uncomfortable Statements
Justin Salamon
Invited talk, Machine Learning for Music Discovery workshop, International Conference on Machine Learning (ICML), Long Beach, California, USA, June 2019.
[PDF][Video]

SUPPLEMENTARY MATERIAL:

Figure 1 (see paper for details):

Figure 1: (a) ground truth melody f0 (pitch) sequence, (b) first algorithm's melody estimate, (c) second algorithm's melody estimate.

Bioacoustics Datasets: A New Website Listing Bioacoustics Datasets and Repositories

25/5/2019

I couldn't find a centralized list of #bioacoustics datasets (for #machinelearning or otherwise), so I created this page. Feedback welcome! #opendata https://t.co/42YHDBiBtM
â€” Justin Salamon (@justin_salamon) May 24, 2019

To explore Bioacoustic Datasets, a centralized list of bioacoustics datasets and repositories, visit: https://bioacousticsdatasets.weebly.com