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Battle of the DJs: an HCI perspective of Traditional, Virtual, Hybrid and Multitouch DJing

16 Apr

To be presented at NIME 2011 (New Interfaces for Musical Expression, Oslo ). The remainder of the program is very interesting, so please feel free to look around here.

What about DJing?

How does it equates within an HCI perspective?

What forms of interaction exist with DJ gear?

How can one classify those interactions/gear?

The following paper addresses these questions, trying to create a framework of through concerning DJ interactions – a very idiosyncratic type of “music interfaces” – and proposes an evaluation of Traditional (analogue turntables, mixers and CD players), Virtual (software), Hybrid (traditional and software in synergy) and Multitouch (virtual and traditional in synergy).

The term multitouch here defines not a categorization but rather an implementation of a touch sensing surface DJing prototype. Explorations among new interfaces for DJing has already been hapenning for at least 10 years, but an evaluation from such perspective (interactions and devices) can aid researchers and developers (as well as DJs) to understand which tools fit in which style. 


Update on my publication list

11 Dec


Articles in International Conferences

1) Multitouch Djing Surface, Pedro André Santos Afonso Lopes, 2010, ACE ’10: Proceedings of the 2010 ACM SIGCHI international conference on Advances in Computer Entertainment Technology (BibTeX)

Multitouch Djing Surface (paper) ( ace2010-pedrolopes-mtdjing.pdf)


Articles in International Conferences

2) Battle of the DJs: an HCI perspective of Traditional, Virtual, Hybrid and Multitouch DJingPedro André Santos Afonso Lopes, 2010, NIME ’11: Proceedings of the 2011 New Interfaces for Musical Expression, Oslo (To appear)


Articles in National Conferences

3) Interação Multi-toque no contexto do DJing, Pedro André Santos Afonso Lopes, Alfredo Ferreira, Joao Antonio Madeiras Pereira, 2010, Interacção 2010 (BibTeX)

Interação Multi-toque no contexto do DJing (paper) ( interaccao2010-pedrolopes-mtdjing.pdf)


4) Trainable DTW-based classifier for recognizing feet-gestures, Pedro André Santos Afonso Lopes, Guilherme Fernandes,Joaquim Jorge, 2010, 16th Portuguese Conference on Pattern Recognition (RecPad 2010), (BibTeX)

Trainable DTW-based classifier for recognizing feet-gestures (paper) ( pedrolopesdtw-based_recopad2010.pdf)


5) Transhumance, Pedro André Santos Afonso Lopes, 2010, Future Places – Digital Media and Local Cultures (BibTeX)

Transhumance (page 169 of the Proceedings) ( futureplaces2010.pdf)



6) Mt-DJing: Multitouch DJing Table, Pedro André Santos Afonso Lopes, 2010, Instituto Superior Técnico (BibTeX)

MtDjingPedroLopes.pdf ( MtDjingPedroLopes.pdf)


(updated from the IST official website)

ACE 2010: Multitouch Djing table

5 Dec

Here is the paper, presented at the International Conference on Advances in Computer Entertainment 2010, ACM & SIGCHI at the Interactivity Session.

Interacção 2010 final program announcement

25 Sep

The MtDjing has been accepetd in Interacção 2010 as previously posted, now the conference page already holds a final version of the program, that you can look via web of pdf document.

Our presentation will be held in the first session of the day followed by the talk of Shahram Izadi from Microsoft entitled “Making computers more natural to use”:


Orador Convidado

Making Computers More Natural to Use
Shahram Izadi (Microsoft)

16h00 Coffee Break

Sessão I – Interfaces Multi-toque

Conjuntos de gestos de comando para ferramentas de desenho em dispositivos sem teclado
Tiago Gomes, Carlos Duarte, Luís Carriço, Joana Neca e Tiago Reis

Técnicas de interacção para revisão de cenários 3D
Bruno de Araújo, Diogo Mariano, Ricardo Jota, Alfredo Ferreira e Joaquim Jorge

Interacção multi-toque no contexto do DJing
Pedro A. Lopes, João A. Madeiras Pereira e Alfredo Ferreira

Combining different types of interaction on multi-touch surfaces
Tarquínio Mota

Also in this “multitouch” session we have the presentation of yet another paper from VIMMI group (in this paper: Bruno de Araújo, Diogo Mariano, Ricardo Jota, Alfredo Ferreira e Joaquim Jorge), from the european project MAXIMUS, being presented by my college Diogo Mariano.

Latex: installing miscellaneous fonts and macros

25 Sep

In order to use the book template required by many iunstitutions such as IST (where my Thesis is being completed), check the following packages:

(you can use apt-get, synaptic (my favorite for this things), or aptitude)

  • texlive-fonts-recommended (the basic)
  • texlive-fonts-extra (needed for the template because of cmbr8 font)

As far as other Latex packages I have the following that come in handy for scientific writing:

  • texlive-math
  • texlive-math-extra

Also a lot of usefull macros can be found in:

  • texlive-generic-recommended
  • texlive-generic-extra

Articles getting baked… change of wall poster!

5 Jul

After sending a submission to my first conference as a part of my master proposal, I’m sending a larger, more in-depth contribution to another one, with a emphasis on the system wide view and how all components create a enviroment for DJ performance.

Thus the old poster….


Now looks like this (I’m so lazy I’ve just reversed the paper sheet)


Closer detail for those peeping toms out there…


A lot…….of work, during these past few weeks.

Open Source Flash#8: Get your Adobe Flash Builder 4 Licence (students)

21 Apr

Adobe has moved Flex Builder 3 into Flash Builder 4, unless for Linux – which is still running Flex Builder 3 (alpha stage, wit some issues). The plataform is built on Eclipse IDE and offers some nice features, auto-build, sintax highlight and code completion, and bla bla…

The program is available as a trial version but as a student you can ask for an official serial number, by providing Adobe with your student data. If it suits you, its better than using a trial version of course.

Note: if you are really hardcore, there’s the Flex Open Source SDK with a command line mxmlc compiler.

Scratch/Turntablism Ph.D. Thesis!

9 Apr

Hooray! Kjetil Falkenberg Hansen from KTH has defended his doctoral thesis under the topic of turntablism. You migh take a closer look here (or download it here).

Abstract for the Thesis

This thesis focuses on the analysis and modeling of scratching, in other words, the DJ (disk jockey) practice of using the turntable as a musical instrument. There has been experimental use of turntables as musical instruments since their invention, but the use is now mainly ascribed to the musical genre hip-hop and the playing style known as scratching. Scratching has developed to become a skillful instrument-playing practice with complex musical output performed by DJs. The impact on popular music culture has been significant, and for many, the DJ set-up of turntables and a mixer is now a natural instrument choice for undertaking a creative music activity. Six papers are included in this thesis, where the first three approach the acoustics and performance of scratching, and the second three approach scratch modeling and the DJ interface. Additional studies included here expand on the scope of the papers.

For the acoustics and performance studies, DJs were recorded playing both demonstrations of standard performance techniques, and expressive performances on sensor-equipped instruments. Analysis of the data revealed that there are both differences and commonalities in playing strategies between musicians, and between expressive intentions. One characteristic feature of scratching is the range of standard playing techniques, but in performances it seems DJs vary the combination of playing techniques more than the rendering of these techniques. The third study describes some of the acoustic parameters of typical scratch improvisations and looks at which musical parameters are typically used for expressive performances. Extracted acoustic and performance parameters from the data show the functional ranges within which DJs normally play.

Unlike traditional musical instruments, the equipment used for scratching was not intended to be used for creating music. The interface studies focus on traditional as well as new interfaces for DJs, where parameter mappings between input gestures and output signal are described. Standard performance techniques have been modeled in software called Skipproof, based on results from the first papers. Skipproof was used for testing other types of controllers than turntables, where complex DJ gestures could be manipulated using simplified control actions, enabling even non-experts to play expressively within the stylistic boundaries of DJ scratching. The last paper describes an experiment of using an existing hardware platform, the Reactable, to help designing and prototyping the interaction between different sound models and instrument interfaces, including scratching and Skipproof.

In addition to the included papers, studies were conducted of expressivity, description of the emotional contents of scratching, DJ playing activities, and the coupling between playing techniques and sample. The physical affordances of the turntable, mixer and samples, as well as genre conventions of hip-hop, are assumed to explain some of the findings that distinguish scratching from other instrumental sounds or practices.

Flash and TUIO libraries! (open source)

7 Apr

There are a lot of Flash <-> TUIO libraries, primarily intended to bring the Multitouch TUIO standard to Flash in an API style. Because AS3 is pretty much developed towards the concept of Event Handling (attaching events with functions that are dispatched by the AS3 itself) these libraries work in a similar way to. There are a few possibilities that I’ll show here:

Tuio-AS3-Library (link & download)

This is a small framework that allows you to do the basic stuff with the TUIO messaging under ActionScript3, it supports:

  • TUIO 1.1 (the latest spec)
  • Cursors, Objects and Blobs in 2D, 25D & 3D
  • Binary data stream via TCP & LocalConnection (because AS3 does not use UDP – this is changing as we speak)
  • Callbacks & legacy TouchEvents
  • Fully implemented OSC parser (very important, this is the way you extract information from a packed TUIO/OSC message)

Their website describes it quite nicely (see diagram above), although in a very brief testing I had some problems with the linkage in both Flash Builder 4, Flex Builder 3 and even command line MXMLC (Flex Compiler from Open Source Flex SDK) – it may be  simple problem that I’m overlooking, I’ll post more as soon as I can get it running here.

TouchLib (stronger lib – download link)

The main thing about TouchLib is that it comes packed with AS3 classes to work with TUIO, therefore it offers the same basic funcionalities as above (listening to the TUIO messages, parsing them, etc…), then it comes with something extra: AS3 classes that allow you some funcionality (very typical of Multitouch):

  • Automatic rotate, scale and move of the canvas objects (via
  • and all the stuff of the previous lib…

Make sure that you understand that ToucLib is indeed a CV tracker, intended to multitouch tabletops, it is written in c++ and uses OpenCV.dll but has now been replaced with CCV, what we want here is the Classes of AS3 that comes with TouchLib files from svn, that allow us this multitouch flash behaviour.

You can also check some projects that make use of the TouchLib AS3 classes for Multitouch here (they make interesting demos..).

FiducialTUIOas3 (download here)

This fiducial AS3 framework enhances the Touchlib’s AS3 classes with Tuio object interaction functionality.

The adapted Touchlib’s TUIO AS3 classes are included. To make it even clearer: You don’t need any other TUIO AS3 classes then those of fiducialtuioas3 as fiducialtuioas3 supports both multi-touch AND fiducials. It’s complete. You can even use fiducialtuioas3 if you only want to implement multi-touch interaction.

Here’s a demo on a project that uses flash + multitouch + fiducial tracking.


TUIO-As3-Lib (download link)

This a small scaled library (with a very similar name to the first one, although they are two different libs) that allows you to receive and parse TUIO messages via As3. This is very simple to use: just include the .swc component in your project or command line include argument. The functionallity is stripped down to minimum, but if this is all you need it might just suit you nicely. Here’s my first demo with this lib.

Testing the Tuio-AS3-lib on a multitouch table from PedroLopes on Vimeo.

Do not mind: the non-calibrated touch points!

I’ve built a “Hello World”-like demo to test the features of TUIO-AS3-lib. It is distributed in either Source or SWC (external component for import). The demo instantiates 3 string objects, they are assigned to an array that is check everytime a touch event arrives in TUIO-AS3-lib listener – this way for each object the colision is detected. I use CCV (tracker) & an ActionScript 3 project (that imports the external SWC of the lib). Some thoughs about TUIO-AS3-lib: interesting project if you just need to listen to the events and implement your interface on top. Simple and plain code, easy to follow. Although it does not implement the same level of features as a full scaled multitouch framework like touchlib that offers scalableObjects, rotatable, and so on…

OSC (Open Sound Control) changes to Open Show Control?

2 Apr

I’ve received this today on OSC mailing list, the name is questionable (a protocol to “put on a show”) although it is a new way to show that OSC has gone much further than “sound” or “new MIDI”. We use it here for blob tracking (on CCV).

someone (-at-)

to osc_dev

show details 6:47 AM (2 minutes ago)

In light of the ever broadening scope of application of Open Sound Control
we have decided to change  the name of the OSC encoding to Open Show

Here are some examples of OSC applications motivating the name change:

– Motion capture data from cameras by Qualisys
– Lighting and theatrical control at the Topological Media Lab.
– VRAS and other acoustic rendering systems at Meyer Sound
– Solenoids at Disneyland
– Motor and Servo control on the Make Controller Kit
– Timely media device control and discovery in IEEE AVB


Update: The name seems to be an open discussion (I hope it is), but the main thing is “OSC delivers more than sound related computing” . That’s whats important.