What Is an Mp3

What is an MP3

An MP3 is a recorded high-quality audio (voice and music) file which can be distributed over the Internet, and played on any multimedia computer with the right sound card and speakers. MP 3 is simply a file format that compresses a song into a smaller size so it is easier to move around on the Internet and store. MPEG is the acronym for Moving Picture Experts Group. This group has developed compression systems used for video data. For example, DVD movies, HDTV broadcasts and DSS satellite systems use MPEG compression to fit video and movie data into smaller spaces. The MPEG compression system includes a subsystem to compress sound, called MPEG audio Layer-3. We know this as MP3.

The music industry distribution medium of audio CD's, or "packages of audio information" (approximately 10 songs), preserves its dominate high sale price through shortage. The true value of a musical artist is found only in what he (or the distributor) can persuade or force people to pay for the privilege of listening. It does not matter how much of a "good idea" it is to have such laws to protect the artists. People will listen without paying, because they can.

If the musician wants protection from unauthorized listening of his live performances, that he should find some form of self-protectionÐŽXby only performing for small groups of people or for audiences that agree to pay for entrance into an auditorium? And that he should stop crying about people listening to him sing in public without pay, and about the police not arresting the illegal listeners?

This is exactly the type of situation that is developing with the new breakthrough digital audio format called MP3 combined with the Internet. The heart of the matter is not morality, but enforceability.

Audio Copyrights and Other Delusions

The same is now true of existing audio copyright issues. They are absolutely unenforceable, and will not protect the artists. Only the morality of the public will protect the music industry, and the morality of the public does not hold much promise for existing copyright issues. The difference between the industry losing "billions" in audio CD sales from the illegal recording of radio songs on Memorex cassette tapes, and the "billions" it loses in lost sales from the recording of MP3 files is this. MP3 files are easier to copy, distribute, share, and collect. The copies are digitally exact, and the selection is greater to choose from because there are thousands (and soon to be millions) of MP3 broadcasters on the Internet, instead of the limited selection of songs that are played on the local radio stations. Many believe there is no moral difference between pressing "Record" on a cassette player, while listening to their favorite radio or cable TV music channel, and hitting the "Save to Disk" button on any MP3 file that they run across.

The MP3 Format

A CD stores songs as digital information. The data on a CD uses an uncompressed, high-resolution format. Specifically here's what happens to create a CD:

„h Music is sampled 44,100 times per second

„h The samples are 2 bytes (16 bits) long

„h Separate samples are taken for both the left and right speakers in a stereo system

Therefore a CD stores a huge number of bits for each second of music:

44,100 samples/second * 16 bits/sample * 2 channels = 1,411,200 bits per second

1.4 million bits per second is 176,000 bytes per second. If an average song is 3 minutes long, then the average song on a CD consumes about 32 million bytes of space. 32 Mbytes is a lot of space for one song, and it is especially large when you consider the bandwidth most people have available for their Internet connections. Over a 56k modem it would take something close to 2 hours to download one song. The MP3 format is a compression system for music. The MP3 format helps reduce the number of bytes in a song without hurting the quality of the song's sound. The goal of the MP3 format is to compress a CD-quality song by a factor of 10 to 14 without losing the CD quality of the sound. With MP3, a 32 megabyte song on a CD compresses down to 3 megabytes or so. This lets you download a song in minutes rather than hours, and it lets you store hundreds of songs on your computer's hard disk without taking up that much space. If you wanted to, you could download an MP3 file, expand it back to its original size and then record it on a write-able CD so you could play it in the CD player in your car. All that you are doing is converting back and forth between different formats to make downloading easier.

MP3 files are not illegal. What is illegal is taking copyrighted music from an artist's CD, encoding it in the MP3 format to make it smaller and then giving that music away for free on the Internet without the artist's permission. That violates copyright laws and also cheats the artist.

Is it possible to compress a song without hurting its quality?

We use compression algorithms for images all the time. For example, a GIF file is a compressed image. So is a JPG file. We create ZIP files to compress text. So we are familiar with compression algorithms for images and words and we know they work. To make a good compression algorithm for sound, a technique called perceptual noise shaping is used. The "perceptual" part in the name means that the MP3 format uses characteristics of the human ear to design the compression algorithm. For example:

„h There are certain sounds that the human ear cannot hear

„h There are certain sounds that the human ear hears much better than others

„h If there are two sounds playing simultaneously we hear the louder one but cannot hear the softer one.

Knowing this, certain parts of a song can be eliminated without significantly hurting the quality of the song for the listener. Compressing the rest of the song with well-known compression techniques shrinks the song considerably. When you are done creating an MP3 file, what you have is "near CD" quality. The MP3 version of the song will not sound exactly the same as the original CD because some of the song has been removed, but it will be close.

Downloading and Listening to MP3 files

If you would like to download and then listen to MP3 files on your computer,