The term "MP3" is surely not a novelty. The layman is aware that it is an audio format or an audio file extension. MP3 tracks are probably heard on a daily basis, on computers, in cars, on portable MP3 players, and smart phones too. Features, like impeccable sound quality and large memory capacity attract us to this amazing format. MP3 stands for 'MPEG-1 Audio Layer 3'.
MPEG stands for Moving Picture Experts Group, which was set up by the ISO in 1988 to set standards for compression and transmission of audio and video files. The "1" in MPEG-1 Audio Layer 3 indicates that it was the first compression standard formulated by the group. This was followed by the MPEG-2, which upgraded the commonly-used format for digital video transmission. As audio files have a much more simple encoding, MPEG-1 is just the right standard to achieve optimum quality audio. The "3" in MPEG-1 Layer 3 stands for the use of third audio codec that was formulated in the MPEG-1 standard. The Layer 1 codec was known as Mp1, and was used mostly on digitized compact cassettes at 384 kbit/s. The layer 2 codec is still in use, and has been introduced as a standard for audio broadcasting.
MP3 - The Meaning
- MP3 denotes a digital audio encoding format. It is a common and the most preferred audio format for storage and transfer of audio files.
- It is also a de facto standard of audio compression for the playback on digital audio players.
- MP3 uses a lossy compression algorithm in order to greatly reduce the number of data bytes required to encode the audio track, and still sound like an exact reproduction of the uncompressed original audio track.
- An MP3 file that is produced by encoding a 128 Kbps audio track will be about 1/11th the size of an original CD audio track, which was the analog representation of the original audio source.
- An MP3 file can also be encoded at frequencies of higher or lower bit rates, where resulting quality may change.
How Does MP3 Work?
- As stated earlier, MP3 is a digital audio codec. This means, it provides a method of compressing and decompressing sound files.
- In a standard audio CD, tracks occupy about 10 MB of data per minute of playback.
- When a song is ripped or converted from a CD in a computer to an MP3 track, then one minute of music can be reduced to less than 1 megabyte - an eleventh of the original file size.
- The compression algorithm works by compromising accuracy of certain segments of soundtrack that are viewed as beyond the human auditory resolution, i.e., the sound processing ability of most humans, which is known as perceptual coding.
- A psychoacoustic model is used in this algorithm, which reduces or discards precision of the sound components, which are less audible to human ears, and encodes the remainder of the track information in an efficient manner.
- Therefore, MP3 codec is a lossy format of compression, i.e., some frequencies are lost forever in the encoding process, and even after reconverting the file to its original format, they cannot be restored. This technique is conceptually similar to the algorithms used in the image compression format JPEG.
- In spite of having a lossy characteristic, MP3 audio format can deliver sound close to CD quality.
- There's an option of adjusting audio frequencies in MP3. Just as we can save digital photos at different resolutions to save memory space or to enhance quality, we can adjust the frequency or 'bit-rate' of an MP3.
- The bit-rate is the average amount of data bits per second of music played.
- It determines the audio quality or resolution of an MP3.
- Higher the bit-rate, closer the sound quality of the MP3 file to the original audio file, and larger is the file size.
- The MP3 format was developed by a German company named Fraunhofer-Gesellshaft, in the late 1980s.
- This company also holds the patent to MP3 technology, which was granted to them in 1989.
- In 1987, the Fraunhofer Institut Integrierte Schaltungen research center, a subsidiary of Fraunhofer-Gesellshaft, initiated a novel research on high-quality, low-bit rate audio encoding with a project named 'EUREKA EU147'.
- The main person responsible for the development of MP3 was Karlheinz Brandenburg, who is widely considered as the 'father of the MP3'.
- He was a mathematician and also specialized in electronics. He started researching on audio compression techniques from 1977.
- There were several hurdles in course of developing an MP3 player. In fact, in 1991, during modification testing, the encoding just refused to work.
- Two days before the final submission of the first modified version of the MP3 codec, they identified a compiler error and solved the bug.
- In 1993, the first MPEG-1 standard was published, followed by the updated MPEG-2 standard, which was developed and published the next year.
- After this point on, there was no looking back. MP3 format enjoys a monopoly in the audio market till date and the latest MP3 players loaded with enhancement software have only improved the listening experience.
This article only provides a gist of the MP3. Many formats have arrived and perished, but none could even shake the legacy of the MP3.