What is an MP3?

Damir Wallener

An MP3 is a digital audio file compressed with a standard defined by the Motion Pictures Experts Group (MPEG). MPEG was formed to develop techniques for dealing with digital video; since most video also contains audio, this format was developed as an audio extension of that work. Officially known as "MPEG-1, Layer 3", MP3 is a lossy compression algorithm that uses psychoacoustic modeling to reduce the size of audio files by up to 90%.

MP3 is a lossy compression algorithm, reducing the size of audio files by up to 90 percent.
MP3 is a lossy compression algorithm, reducing the size of audio files by up to 90 percent.

Psychoacoustics takes advantage of deficiencies in the human hearing system to throw away digital bits corresponding to sounds that cannot be heard. The human ear cannot hear soft sounds in the presence of loud sounds having a similar frequency; for example, a voice conversation becomes inaudible when a jet flies low overhead. This effect is known as auditory masking, and done correctly, the discarded sounds will not be missed.

Psychoacoustics relies on deficiencies in the human hearing.
Psychoacoustics relies on deficiencies in the human hearing.

MP3 is a lossy algorithm in the sense that the original bits cannot be recreated from the compressed bits. In terms of hearing, however, the format is lossless because the human ear cannot distinguish between a CD recording and a properly encoded version of it. MP3s achieve this transparency at a bit rate of approximately 256 kilobits per second, or roughly one-sixth of the 1.4 megabits per second required by the compact disc format.

It is possible to record MP3s at lower bit rates, saving even more space, but audible differences begin to appear at rates below 128 kilobits per second. At these lower bit rates, the format can use a trick known as joint stereo to improve quality. Audio generally consists of left and right audio tracks. Joint stereo combines, whenever possible, the sounds common to both left and right tracks into one track. Instead of left and right, it has "common" and "different" channels.

Being an open standard, and therefore available to anyone, has played a major role in the widespread adoption of the MP3 file format. While specific implementations, such as those by the Fraunhofer Institute, may be protected by patents, there exist numerous open source implementations. Files in this format were originally only playable on computers, but inexpensive, portable players have since been developed.

Handheld MP3 player with earbud headphones.
Handheld MP3 player with earbud headphones.

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Discussion Comments


In the full form of Mp3, most probably it would be, Music plus plus plus.

Because C + + so C comes here computer programming language or charles for charles babage. Or it could be co-program or c drive or anything.


I often wondered why some of my CDs did not have sound when I try to play them in my car. I did not choose "audio" when I was making copies.


@wavy58 – If you want to be able to listen to the CD on just about any player, then you should choose the “audio” option. I went through the same thing when I burned my first CD, and I made the wrong choice.

I told my computer to make a data CD. While it would play just fine on my computer, it would not work in my car's CD player. I had to go back and make another CD, and this time, I chose “audio.”

An audio CD can be played in a DVD player, a computer, or a regular CD player. It's best to use this option for mp3 music.


I've been wanting to burn my mp3 songs onto a CD so that I can listen to them in my car, but I am a bit confused by the process. I inserted a CD into my computer and told it that I wanted to burn the songs onto it, but it asked me whether I wanted an audio CD or a data CD.

I'm guessing I should go with the “audio” option, but I don't want to choose the wrong thing and waste a CD. What is the difference between the two, and which one can I play in my car's CD player?


@shell4life – Those free mp3 files were not all of great quality, though. I also downloaded several at the time, and many of them were lacking in sound quality.

Some of them were too quiet, and others were way too distorted. It used to take a really long time to download even one song back when I had dialup, so it was always very disappointing to finally get a song totally downloaded and find that it sounded awful.

One good thing about sites that make you pay for songs is that you know you will be getting something that sounds like it is supposed to. These sites have a reputation to maintain, so they make sure all their mp3 files are high quality.


I remember when I first heard about mp3 files. This was back before record companies outlawed free mp3 downloading, so I built up quite a collection of these music files when it was still legal.

I would listen to them on my computer as I worked. It was really nice to have music stored in there and available to me at the click of a button.

I was really bummed when it became illegal to download mp3 files for free. I had to start choosing which songs I felt were worth the 99 cents it took to download them, and since I didn't have much money back then, my collection stopped growing at a fast rate.


Thanks, this really helped me with my science project.


Sounds great!


How the songs are stored in the memory card and how the songs are played from the memory card?


whats the full form of MP3


how can I create an MP3 disc for my vehicle?


How do I record my old CD's to MP3.


can I transfer my CDs to my mp3 digital audio player


Anyone can hear the differences between the best MP3s and the best CDs!

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