What Are MP3s?

• MP3s, shorthand for MPEG-1 Audio Level 3, are files that contain digital audio information. Because they are compressed, MP3s are usually referred to as "lossy" audio files, meaning they some data during conversion. While other file formats are "lossless," or lose no data during conversion, they use more storage space and are more difficult to create. The small size, ease of creation and widespread use of MP3 files make them the preferable format for digital audio players.
  
  

Converting Music

• When you put an audio CD into your computer, you typically open it with a program to play the music. Hardware inside your computer reads the CD as electrical signals and sends them to your speakers, which output the signals as sound. Converting CD audio to MP3s uses a similar technique, without outputting the sound. Instead, the electrical signals are sent to a program, the analog-to-digital converter, which converts them to data that are understood by the computer. This data is sent to another program, known as a codec, which converts it to a specific audio format, such as MP3. The codec is used again when the computer reads the file. It reverses the process by converting the MP3 data to electrical signals that are output to the computer speakers as audio.
  
  

MP3 Bit Rates

• The analog-to-digital converter samples, or captures, the electrical signals at different speeds, which results in bit rates. This process is similar to the frame rate for films. High-quality cameras capture more frames per second, which results in a clearer video. Likewise, higher quality MP3 files will have a higher bit rate.
  
  

Creating MP3s

• If you have a large library of CDs, you've probably considered moving them to digital format to save space. Luckily, MP3s are easily created with a number of different computer programs. Usually, MP3 players come with such software or make it available for download. The software reads the information from a CD, converts it to digital data and compresses the data to the MP3 format.
  
  

Tagging MP3s

• Once you have created a MP3, you can add file specific information, known as ID3 tags. These tags include artist, title and album, and are used by computer programs and MP3 players to identify songs. ID3 tags are important when using MP3 players, since most organize the songs by artist and album. Without the tags, the MP3 player will display only the file name and will be unable to sort the files correctly. The computer program you use to create the MP3 will allow you to tag the file as well, and many offer the option to connect to an online database to automatically tag all the MP3s created from a CD.