Twenty-three years after the first Walkman, its natural successor -- the handheld video machine -- is ready for its close-up. A new compression format called MPEG-4 finally makes it feasible, and Korea-based MagicEyes Digital gives us a peek at what to expect with its $250 MkiVki. The tiny (3.7- by 2.8- by 0.9-inch) handheld is designed to synchronize MP3 music with images, but the company says future models will support full-motion MPEG-4 video. Philips has also shown a prototype that downloads video wirelessly from the Internet. The first personal video machines should hit the market within two or three years.