When shopping for MP3 players, the following terms may pop up either on the box or the advertisements. You might already know what some of them mean; others might be completely foreign. Either way, here's a translation of what you could encounter.
Skip protection
When you shake a CD player, the laser read head inside moves, making the sound skip. So, those clever engineers added skip protection. When your CD player starts reading the CD, it reads some of the song in advance, storing it in memory that isn't affected by movement. Then, should the little laser doohickey get jostled, the player reads the music from the memory - the buffer. Skip protection technology keeps the song playing smoothly.
Sometimes skip protection is measured in seconds - the number of seconds of music that's read ahead. Other times, skip protection is measured by the amount of memory used to store the music. Either way, the larger the number, the smoother the song plays under rough conditions.
Microphone
Everybody stumbles on a key thought from time to time that could change their lives - if only they could remember it when they got home. So some MP3 players add a microphone for recording those thoughts that seem so important at the time.
Beware, however: MP3 players don't record sounds in MP3 format. They record them as a WAV file. An MP3 player also records sounds in a low-quality format that's fine for speech but lousy for everything else. Most limit the recordings to a few minutes, as well. Even if you do smuggle one into a concert, you'll get only a bad recording of the first part of one song.
Directory and subdirectory restrictions
Some people meticulously organize their MP3 collections. They create one folder called MP3 and then create folders inside that folder for each artist. Next, they create folders in each artist's folder, one for each album. This meticulous organization makes it easy to find songs on a huge hard drive.
However, some players don't recognize all this work. They want all the songs lumped together in a single folder. That makes it harder for you to pluck the right song from a big pile. This might just be a minor inconvenience, but beware of it, nonetheless. (If the manufacturer's Web site doesn't hold such nuggets of information, a little research online should pinpoint reviews of just about any player you're considering.)
ID tags
MP3 files contain more than music. The format includes space for people to add information about the music: the artist, song, album, type of music, recording year, and other interesting tidbits.
Even if a file is named incorrectly, an MP3 player can look at the tag (assuming that it's been filled out correctly) and find out what song is really inside the file.
The best players read ID tags and display the information on-screen, making it easy to see what's being played. The worst players ignore the ID tags and just display a number in place of the song's title.
As the MP3 format evolves, so does the ID tag format. In fact, it's gone through several incarnations, with the most popular being either ID3v1 or ID3v2. ID3v2 is growing in popularity because it holds more information about the song - even a picture of the CD cover, if desired. However, some players can handle only the earlier, ID3v1 tag. That frustrates people who have meticulously entered ID3v2 information into their 563 MP3 files.
Playback options
Does the player simply play all your songs in a row? Can you program them to play back in a certain order? Can it shuffle them randomly so that you don't get tired of the tunes as quickly? When it shuffles them randomly, does it always use the same random order? Don't laugh - it happens.
Power
Portable players come with batteries. But are the batteries replaceable or rechargeable? There is a tradeoff. Rechargeable batteries are cheaper in the long run, unless you're living in California during a power crisis. But if they run out during the afternoon, you can't zip into you local convenience store and grab some new ones. You're stuck.
How long do the batteries last? And does an AC adapter come with the player, or do you have to buy it separately?
Accessories
Many MP3 players, eager to stand out among the competition, toss in some extra goodies: a power adapter that plugs into your car's cigarette lighter, for instance. How are the earphones? Does it have a carrying case? And, if you'll be jogging with it, does it come with a belt clip?
http://tech.yahoo.com/gd/getting-the-good-word-on-portable-player-terms/153218;_ylt=AnHn1gzn2jI9WmJpfG_nBkISLpA5
