How Do MP3’s Work? By Virginia Ellis 2004
History Of MP3 1985 2004 1989 1999 1990 1997 • Started in the mid 1980’s at Fraunhofer Institute in Germany where they began developing a high quality, low bit-rate audio format • 1989 they were granted a permit for the MP3 compression format • Fraunhofer developed the first MP3 player in the early 1990’s
History • 1997 a developer at Advanced Multimedia Products created the AMP mp3 playback engine, which was regarded as the first mainstream machine • MP3 craze started with many types of software available:MP3 encoders, CD rippers, Mp3 players
History • 1999 the first P2P (peer-to-peer) file sharing software application released, Napster by a university student has greatly effected the music industry One of the most famous P2P sharing sites Napster relaunched! Legal and easy to use!
What is MP3? • MP3 is a form of compression, stores sound in microchips instead of a disk or tape • Stands for MPEG Audio Layer Moving Picture Experts’ Group developed by the Fraunhofer Institute
What is MP3? • MP3 files can be compressed at different rates, higher ratio of 10:1 is equal to about 1 MB for each minute of an MP3 song • Fraunhofer has a license on MP3 that if anyone else wants to develop further technology they have to ask them first before making it
A Dummies guide to MP3 Words • Bit rate-name given to the amount of data an application handles per second, Mp3 with high bit rate has excellent sound reproduction • Burn-given to the process of recording a CD • byte-eight bit string of information
Glossary Continued • Decoder-a software or device that can change one file format back to another, MP3 to AIFF • Gigabyte-(GB)equal to 1,024 MB • MIDI-known as Musical Instrument Digital Interface which is the format by which music is generated by the interface of synthesizers and computers together
How Do MP3’s Work? • Variety of compression levels, the higher the k-bit the better quality of sound • Legal to rip MP3 tracks from CD for only personal use • Ripper copies the song’s file from hard disk • Encoder gets the music into the MP3 format (compression) so you can listen to it on your player
The 2 Main Tools The ripper gets music from somewhere else (ex. CD to MP3)and downloads it into your data. The encoder,the key tool used with MP3s. This gets it into the right format
The Process of Compression The encoding tools-rippers and encoders! 1. Encoder analyzes incoming signal determining the “spectral energy”, and breaks it down into a mathematical patterns, and compares it with psychoacoustic models stored in the encoder itself 2.Encoder can then discard most of the data. The person encoding can specify how many bits can be alloted to storing each second of music. More discarded the worse the music!
Process of Compression 3.Goes through a second stage of compression, the “Huffman Coding” which shrinks the remaining data in the traditional zip way! MP3 files have frames like a film strip. They have headers and labels in them sometimes telling what they are. 4. The frames are assembled into a serial bitstream MP3 uses 2 compression techniques to achieve the best audio and throws away inaudible sound by humans
How is compression possible? • The size is reduced so the higher frequency is taken out • Irrelevant data is removed from the audio bit stream • Increase the bit rate for better quality
Psychoacoustics A lot is known about it, described accurately in tables, charts, and in mathematical models representing human hearing patterns. This is the range of possible human hearing Hz.
What is Psychoacoustics? • Uncompressed audio (found on CDs), stores more data than your brain can actually process • For example if 2 notes are similar and very close together, brain might perceive only one • If 2 sounds are very different but one is much louder than the other brain might perceive the quieter one
The Algorithm The algorithm helps divide the MP3 file into sub bands for the most optimal result Fi-lossy is one form of compression where some of the data is lost.
How Transferring Works • Download songs off a legal site to avoid piracy • Make a playlist or mix of your music • Plug the player into computer’s parallel or USB Port (shown above) with a link • Transfer files
Advantages of MP3 players to CD players • Takes up less file space than the CD format WAV/AIFF • You can access legal downloads and get them onto your mp3 player faster, and more music! • Has no moving parts, so it won’t wear out like a CD player will
The iPod iPod memory/price. Also available in mini for much less $! iPods are a big part of music culture these days. You can go anywhere with them!
Cutting Edge Technology • Lighter than 2 CDs, can hold 10,000 songs! • iTunes music store and purchase songs for about 99 cents each • Offers high speed of transfer from an album to your computer • Supports popular audio formats with smaller size so you can fit more songs! The iPOD
Next Generation of the Music Business? • Millions of songs are shared everyday by millions of users • MP3 technology is constantly advancing • With shareware people can trade music with others and people will not buy as many CDs from the store Dell MP3 player Less CD buying
Common Misconceptions • False:That MP3s are the players, not true. They are file formats! • False:All MP3 file sharing is illegal. In fact there is software that is legal and even faster than other file formats. • True:Its the best way to carry your music with you!
Bibliography • Brain, Marshall; Tyson, Jeff; Freudenrich, Craig C. “How MP3 Players Work.” HowStuff Works. 6 May 2004. <http://www. electronics.howstuffworks. com/mp3- player3.htm • Hacker, Scot. “MP3:The Definitive Guide.” 18 May 2004. <http://www.oreilly.com/ catalog/mp3/chapter/ch02.html>. • Nijmeh, Gabriel. “Behind the Files:History of MP3.” 26 April 2004.<http:// kosmoi. com/computer/software/mp3/>.
About the Author Hi, my name is Virginia Ellis. I enjoy swimming, soccer, field hockey,sailing, crafty junk, and hanging out w/ my homies and chicas. maybe I’ll get an MP3 player next Christmas! A golden mini iPod. Hot stuff!
Bibliography • Unknown Author. “What is MP3, how does it work, what is MPEG.” MP3 For Mac. 26 April 2004. <http://www.mp3 -mac.com/Pages/ what_is_MP3.html>. • Unknown Author. “Apple iPod.” GizmoHighway. 26 April 2004. <http://www. gizmohighway.com/personal tech/ ipod.htm>.