In 1999, while he was working as a graphic designer and a technical director in an advertising agency in France, he made the "DivX ;-)" 3.11 Alpha video codec (the smiley was a part of the name) by hacking the Microsoft MPEG-4v3 codec (which was actually not MPEG-4 compliant) from Windows Media Tools 4 codecs. His hack had the advantage of supporting the AVI formatted files. Initial peer-to-peer rapid spread of the program turned into its introductions to the markets. As a result, a company was established.
The new project was first given the name ProjectMayo, and an open-source MPEG-4 codec called OpenDivX was made. It was later changed into a proprietary, closed-source product and the name was changed to DivX (dropping the smiley from the original MSMPEG-4 hack). Rota joined the company DivX, Inc. (formerly known as DivXNetworks, Inc.), based in San Diego, in 2000. The company employed up to 300 employees by February 2007.
- Cave, Damien (15 March 2001). "Escaping the Napster trap". Salon. Archived from the original on 29 November 2010.
- Paolo Poli Come si fa a usare il formato DivX 2005 p 6 "È stato inventato nel 1998 dall'hacker francese Jérôme Rota (nickname “Gej”). ... Jérôme Rota era un esperto programmatore ed è pertanto riuscito a violare la tecnica di codifica Microsoft, utilizzandola per creare il primo codec video DivX, ..."
- Les mots de l'informatique: Dictionnaire illustré pour bien Daniel Ichbiah - 2007 -...p92 "DivX, une initiative française - Né à Montpellier, Jérôme Rota a suivi des études d'électronique et de cinéma. Alors qu'il travaillait comme infographiste dans une société de prestation audiovisuelle, il a été amené à opérer des compressions ..."
- Allbritton, Chris (30 July 2000). "MOVIE PIRATES ATTACK THE WEB New software reduces the price of a ticket to $0". Daily News. Archived from the original on 29 November 2010.
- "VirtualDub documentation: codecs". www.virtualdub.org. Retrieved 8 August 2009.
- "Video Codec Definitions". www.FOURCC.ofg. Retrieved 8 August 2009.
- Stam, Nick (11 January 2005). "DivX: Full Stream Ahead!". PC Magazine. Archived from the original on 29 November 2010.