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Mediathena - BP pour CRI de Paris (*) - 18/06/2019

With Antescofo, musicians never have to practise alone again

Set up in 2016 by three researchers from an Inria-Ircam*-CNRS team, Antescofo provides classical musicians with the opportunity to practise using an application that plays the orchestral accompaniment in high-quality sound and adjusts in real time to any errors they make. The start-up, supported by Inria, is backed by prestigious investors. It is planning a large-scale commercial launch at the end of 2019.

All musical instrument teachers know that it is the austere nature of the hours spent practising alone that undermines students’ motivation and leads some to abandon music altogether. Therefore, when an application available on smartphones and tablets provides students with a full orchestra at home, it instantly becomes a hit. Available without any advertising during the testing phase, the Metronaut application has already been downloaded 200,000 times in the United States, Europe, China and elsewhere.

An app that behaves like real musicians

“A traditional recording imposes its tempo and uses all the instruments provided by the composer. Our application adjusts to the student’s playing style and plays a version without the instrumental part played by the student,”explains Arshia Cont, one of Antescofo’s founders. “It behaves exactly like musicians in rehearsal.” If the student misses a cue, the orchestra stops. If he plays a wrong note or misses a bar, the orchestra continues to play. If he slows down imperceptibly, the orchestra slows down with him. And of course, the sound quality is never impaired. 


Metronaut also allows users to set a slower or faster tempo, or to transpose a piece for another instrument, to play a concerto written for the violin on the clarinet, for example. And all this with exceptional sound quality: “We record the pieces in the studio, with major orchestras and renowned performers.”

Machine learning and mission-critical real time

The software tools capable of accomplishing this feat have been developed over nine years by an Inria-Ircam-CNRS research team and by Antescofo’s continuous R&D. In addition, since the application was made available, there have been regular testing and improvement cycles. “The priority at the moment is not sales,”says Cont.“We continuously analyse the behaviour of our users and engage in dialogue with them.”


Functionally, Metronaut makes a sound recording, listens to the musician who is practising, and adjusts the accompaniment if necessary, ideally in less than 20 milliseconds so that the student does not perceive a delay. “We use machine learning and mission-critical real time (see Box 2), which is also used to fly aircraft.Recently, we have also been working on further reducing this adjustment time.”


 “Setting up a start-up means becoming very small and very fragile”

For Antescofo’s three co-founders, renowned researchers in their field, the big leap into their entrepreneurial adventure signalled a sudden change in status. “You suddenly become very small and very fragile, in an unknown professional environment where no one trusts you at first,”says Cont. To negotiate this challenging exit from the lab, the team first relocated to Agoranov, a high-tech incubator in Paris. It was then based at Station F, another Paris-based incubator that is home to more than 2,000 entrepreneurs. Here, the team met Nobuyuki Idei, former CEO of Sony, who participated in a €4 million fundraising campaign in early 2019.

Inria’s support: funding, visibility, credibility

Inria closely followed the launch of this new venture, supported its protégés and provided crucial assistance at key moments. When the start-up was set up, Inria acquired shares in it and funded the salaries of two engineers for a year. It then completed the licence negotiation for Antescofo’s patents in just a few months. This can sometimes take years. 


Inria continues to regularly invite Antescofo to conferences and trade shows. “We have more visibility and credibility than most young start-ups.” For example, in 2017, during a business event, Arshia Cont had the opportunity to meet Yann LeCun, Director of Artificial Intelligence Research at Facebook. Since then, this world-renowned researcher** has also become a shareholder of the start-up. 


* Institute for Acoustic/Musical Research and Coordination

** He was co-winner in March 2019 of the Turing Prize, considered to be the equivalent of the Nobel Prize in computer science

Antescofo: five key dates

• July 2016:set up by three researchers: Arshia Cont, Philippe Cuvillier and José Echeveste. They were quickly joined by Laurent Tran Van Lieu, former director of Direct Assurance.

• September 2017:Metronaut app launched after 18 months of R&D.

•July 2018:Metronaut was a featured app on the App Store. 30,000 downloads in one day in the United States.

• January 2019:Antescofo relocates with its 15 employees to Paris’s third arrondissement. €4 million fundraising campaign.

• Summer 2019:Antescofo’s catalogue will exceed 1,000 classical compositions.

Find out more about mission-critical real time

 In an aircraft, for example, a delayed response from a computer system can be catastrophic. These are therefore known as “mission-critical real-time systems”: in response to specific physical events (e.g. exceeding a temperature threshold), they respond within a specified maximum time limit that can be expressed in milliseconds or even microseconds. Furthermore, they are fault-tolerant systems: even with abnormal input data, they always behave safely.

By tapping into the critical real-time toolbox, Antescofo ensures that the orchestral part will always adjust to the musician's playing within a short enough time to be imperceptible. Moreover, fault tolerance prevents the orchestral part from stopping when the musician makes the slightest mistake. After all, these errors are part of musical practice.

Keywords: Start-up Antescofo Music