Winamp 4 ((new))

Winamp 4 would have been the battleground for the OGG vs. MP3 vs. AAC war. It likely would have removed the default MP3 encoder (due to Fraunhofer licensing) and pushed the open-source Vorbis format heavily.

According to former Nullsoft developer Christophe Thibault and official statements at the time: winamp 4

By the turn of the millennium, Winamp was installed on more PCs than almost any other third-party software. It was the king. But as the saying goes, heavy is the head that wears the crown. Winamp 4 would have been the battleground for the OGG vs

Contrary to standard software versioning, Nullsoft (later AOL) jumped directly from (released 2002) to Winamp 5 (released 2003). No beta, alpha, or release candidate of a product labeled "Winamp 4" ever existed publicly. The decision was a deliberate marketing and technical strategy. It likely would have removed the default MP3