~ Guest Lecture at MIT - Ethnic Music Analysis: Challenges & Opportunities - Tarsos as a Case Study

Thursday the 3th of May I gave a guest lecture titled ‘Ethnic Music Analysis: Challenges & Opportunities’ it featured Tarsos as a Case Study. The goal was to identify the difficulties when dealing with ethnic music and to show a possible approach, the approach implemented by Tarsos.

The invitation to give the guest lecture came from Michael Cuthbert who is one of the driving forces behind music21. The audience was a small group of double majors in both musicology and computer science: the ideal profile to gather useful feedback.

Computational ethnomusicology en Presentation

2012.05.03-Ethnic_Music_Analysis.pdf en 2012.05.03-Ethnic_Music_Analysis.odp

~ Démonstration de Tarsos

Nous avons creé une video pour expliquer des possibilités de Tarsos, et maintenant en français.

Tarsos, français, en Computational musicology

~ Audio Time Stretching - Implementation in Pure Java Using WSOLA

The DSP library for Taros, aptly named TarsosDSP, now includes an implementation of a time stretching algorithm. The goal of time stretching is to change the duration of a piece of audio without affecting the pitch. The algorithm implemented is described in An Overlap-add Technique Based On Waveform Similarity (WSOLA) for High Quality Time-Scale Modification of Speech.

To test the application, download and execute the WSOLA jar file and load an audio file. For the moment only 44.1kHz mono wav is allowed. To get started you can try this piece of audio.

There is also a command line interface, the following command doubles the speed of in.wav:

java -jar TimeStretch.jar 2.0 in.wav out.wav

The source code of the Java implementation of WSOLA can be found on the TarsosDSP github page.

Java, TarsosDSP, Tarsos, en WSOLA

time_stretching_in_java.png, 08._Ladrang_Kandamanyura_10s-20s.wav, en TimeStretch.jar

~ Kinderuniversiteit - Muziek onder de microscoop!

Zondag 18 december 2011 gaf ik een workshop voor de Gentse kinderuniversiteit. Het thema van de kinderuniversiteit was Muziek onder de microscoop. De teaser voor de workshop is hier te vinden:

WORKSHOP – Muziek (ont)luisteren op de computer
Is het mogelijk om piano te spelen op een tafel? Kan een computer luisteren naar muziek en er van genieten? Wat is muziek eigenlijk, en hoe werkt geluid?
Tijdens deze workshop worden de voorgaande vragen beantwoord met enkele computerprogramma’s!

Concreet worden enkele componenten van geluid (en bij uitbreiding, muziek) gedemonstreerd met computerprogrammaatjes gemaakt in het conservatorium:

• Geluidssterkte: een decibel-meter met een bepaalde drempelwaarde. Probeer zo luid mogelijk te doen en zie hoe moeilijk het is om, eens een bepaald niveau bereikt is, in decibel te stijgen.
• Toonhoogte: een klein spelletje om toonhoogte aan te tonen. Probeer zo juist mogelijk te zingen of te fluiten en vergelijk je score.
• Percussie: dit programma reageert op handgeklap. Hoe kan je het onderscheid maken tussen bijvoorbeeld een fluittoon en handgeklap?

De foto’s hieronder geven een sfeerbeeld.

Presentation, Dutch, en Java

logo-with-arrow.png, UtterAsterisk.jar, PercussionDetector.jar, PitchDetector.jar, en SoundDetector.jar

~ Robust Audio Fingerprinting with Tarsos and Pitch Class Histograms

The aim of acoustic fingerprinting is to generate a small representation of an audio signal that can be used to identify or recognize similar audio samples in a large audio set. A robust fingerprint generates similar fingerprints for perceptually similar audio signals. A piece of music with a bit of noise added should generate an almost identical fingerprint as the original. The use cases for audio fingerprinting or acoustic fingerprinting are myriad: detection of duplicates, identifying songs, recognizing copyrighted material,…

Using a pitch class histogram as a fingerprint seems like a good idea: it is unique for a song and it is reasonably robust to changes of the underlying audio (length, tempo, pitch, noise). The idea has probably been found a couple of times independently, but there is also a reference to it in the literature, by Tzanetakis, 2003: Pitch Histograms in Audio and Symbolic Music Information Retrieval:

Although mainly designed for genre classification it is possible that features derived from Pitch Histograms might also be applicable to the problem of content-based audio identification or audio fingerprinting (for an example of such a system see (Allamanche et al., 2001)). We are planning to explore this possibility in the future.

Unfortunately they never, as far as I know, did explore this possibility, and I also do not know if anybody else did. I found it worthwhile to implement a fingerprinting scheme on top of the Tarsos software foundation. Most elements are already available in the Tarsos API: a way to detect pitch, construct a pitch class histogram, correlate pitch class histograms with a pitch shift,… I created a GUI application which is presented here. It is, probably, the first open source acoustic / audio fingerprinting system based on pitch class histograms.

It works using drag and drop and the idea is to find a needle (an audio file) in a hay stack (a large amount of audio files). For every audio file in the haystack and for the needle pitch is detected using an optimized, for speed, Yin implementation. A pitch class histogram is created for each file, the histogram for the needle is compared with each histogram in the hay stack and, hopefully, the needle is found in the hay stack.

Unfortunately I do not have time for rigorous testing (by building a large acoustic fingerprinting data set, or an other decent test bench) but the idea seems to work. With the following modifications, done with audacity effects the needle was still found a hay stack of 836 files :

• A 10% speedup
• 15 and 30 seconds removed form the needle (a song of 4 minutes 12 seconds)
• White noise added
• Reversed the audio (This is, I believe, a rather unique property of this fingerprinting technique)
• GSM reencoded

The following modifications failed to identify the correct song:

• A one semitone pitch shift
• A two semitone pitch shift
• 60 seconds removed from the needle

The original was also found. No failure analysis was done. The hay stack consists of about 100 hours of western pop, the needle is also a western pop song. If somebody wants to pick up this work or has an acoustic fingerprinting data set or drop me a line at .

The source code is available, as always, on the Tarsos GitHub page.

Audio Fingerprinting Results

Audio Fingerprinting Query

Large scale results

Code, Java, Music Information Retrieval, featured, en Tarsos

x360-dc445.audio_fingerprinting_query.png en AudioFingerprinter.jar

~ Tarsos at 'ISMIR 2011'

A paper about Tarsos was submitted for review at the 12th International Society for Music Information Retrieval Conference which will be held in Miami. The paper Tarsos – a Platform to Explore Pitch Scales in Non-Western and Western Music was reviewed and accepted, it will be published in this year’s proceedings of the ISMIR conference. It can be read below as well.

An oral presentation about Tarsos is going to take place Tuesday, the 25 of October during the afternoon, as can be seen on the ISMIR preliminary program schedule.

If you want to cite our work, please use the following data:

  
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@inproceedings{six2011tarsos,
  author     = {Joren Six and Olmo Cornelis},
  title      = {Tarsos - a Platform to Explore Pitch Scales 
                in Non-Western and Western Music},
  booktitle  = {Proceedings of the 12th International 
                Society for Music Information Retrieval Conference,
                ISMIR 2011},
  year       = {2011},
  publisher  = {International Society for Music Information Retrieval}
}

Computational ethnomusicology, Research papers, Music Information Retrieval, Code, featured, en Tarsos

tarsos_ismir_paper.bibtex.txt en tarsos_ismir_2011.pdf

~ TarsosTranscoder

Tarsos Transcoder is a library to transcode audio with JAVA.

Downloads and more info on http://tarsos.0110.be/tag/TarsosTranscoder

It uses (platform dependent) FFmpeg binaries in the background. It is a fork of JAVE (Java Audio and Video Encoder) by Carlo Pelliccia (www.sauronsoftware.it).

Tarsos Transcoder focuses only on audio and it is compatible with more, and more recent FFmpeg binaries and it less dependent on text output of the different binaries. The interface is also simplified. It falls back to use the ffmpeg binary in the system path, if one is present, therefore it supports platforms for which no binary is provided within the release.

Getting Started

If you have Apache Ant and git installed on your system the following commands get you started quickly:

git clone https://JorenSix@github.com/JorenSix/TarsosTranscoder.git
cd TarsosTranscoder/build
ant #Compiles and builds the core TarsosTranscoder library
ant javadoc #Creates the javadoc documentation in TarsosTranscoder/doc
java -jar tarsos_transcoder-1.0.jar ../audio/input/tone/tone_10s.wav test.flac FLAC_MONO_44KHZ #Test wav to flac transcoding

If you want to use the transcoder from within Java you need to call Transcoder. It is as simple as:

Transcoder.transcode("foo.mp3","foo.wav",DefaultAttributes.WAV_PCM_S16LE_STEREO_44KHZ);

FFmpeg can encode to a lot of audio formats and can decode even more.

Inner workings

Tarsos Transcoder tries to find an FFmpeg binary in the path of the system. If it does not find one it tries to copy a binary for the current platform. Tarsos Transcoder contains three binaries: one for MAC OS X, one for Linux (x86) and one for windows. Tarsos Transcoder has been tested on:

• MAC OS X 10.6
• Windows 7
• Ubuntu linux 10.10 ARM
• Ubuntu Linux 10.04 x86_64

It will probably work most of the time.

Alternative Binaries

If the TarsosTranscoder does not include binaries for you platform, install ffmpeg and add the ffmpeg executable to your system path. It will be found and used by TarsosTranscoder automatically.

Alternatively, providing binaries for your (unsupported) platform can be done by implementing FFMPEGLocator. The PickMe method should yield true on your platform and copy e.g. an FFmpeg binary to a temporary directory.

Lisence

This software is licensed under GPL, TarsosTranscoder is based on JAVE (GPL).

Credits

JAVE (Java Audio and Video Encoder) by Carlo Pelliccia – www.sauronsoftware.it

FFmpeg: this uses libraries from the FFmpeg project under the LGPLv2.1

This product includes software developed by The Apache Software Foundation. It uses the Apache Commons Exec library, licensed under the Apache License Version 2.0

TarsosTranscoder is used by Tarsos, Tarsos is developed at University College Ghent, Faculty of Music

TarsosTranscoder

~ Guest Lecture at MIT - Ethnic Music Analysis: Challenges & Opportunities - Tarsos as a Case Study

Thursday the 3th of May I gave a guest lecture titled ‘Ethnic Music Analysis: Challenges & Opportunities’ it featured Tarsos as a Case Study. The goal was to identify the difficulties when dealing with ethnic music and to show a possible approach, the approach implemented by Tarsos.

The invitation to give the guest lecture came from Michael Cuthbert who is one of the driving forces behind music21. The audience was a small group of double majors in both musicology and computer science: the ideal profile to gather useful feedback.

Computational ethnomusicology en Presentation

2012.05.03-Ethnic_Music_Analysis.pdf en 2012.05.03-Ethnic_Music_Analysis.odp