Japaneese man Kozo Ohsone
1645
The first portable DVD players were introduced in 1998 by Panasonic. While newer portable DVD players have an average screen size of 7 inches, the first portable DVD player's screen was only 5 inches.
Thomas Edison
CD player
In 1979, the first portable cassette player was developed by Sony. It was created for the founded of Sony because he loved listening to music on flights between Japan and the United States. It totally changes the way people listen to music.
It's stored in digital form - in memory chips.
Yes, an MP3 player is considered a portable audio player because you can carry it around with you no matter where you go, and it plays the music you decide to loan onto it.
It would depend on what kind of portable player. Many portable can play CD and DVD. If it had the function to let you play music than .mp3 are the most common format.
The personal stereo is also known as a Walkman. This portable personal stereo player was invented by Andreas Pavel.
2001
Yes, it is. The portable recycling unit is invented.
No, Thomas Edison invented the first "music" player, the Phonograph