The report also explored the revenue potential of three other portable devices that play back compressed audio: DVD players, mobile phones such as the Motorola Rokr and gaming devices such as Sony's PSP. This category of "other" portable play-back devices is expected to exceed 700 million units shipped with an estimated $114 billion in revenue in 2009, IDC said.Read on over here.
Combined with the MP3 player category, all compressed audio players are expected to reach 945.5 million units shipped and $145.4 billion in revenue worldwide by 2009.
Digital audio player shipments to reach 945 million units by 2009

ZD Net reports about a new survey from IDC which says digital audio player shipments will reach record levels in the next four years. The firm claims shipments of flash-based MP3 players will hit a 124 million units peak in 2009, a 370 percent increase from the 26.4 million units shipped worldwide in 2004.