How does MP3 work?
1. The common name for portable MP3 player. a portable player
used to play music in MP3 format (now compatible with wma, wav and other formats).
Portable MP3 Player was originally developed by Korean Wenguang Su and Huang Dingxia (Moon & Hwang) Invented in 1997 and applied for related patents Detailed explanation of the
technology development of the MP3 format Format, which is designed to drastically reduce the amount of audio data, while for most users the playback quality is not appreciably degraded from the original uncompressed audio. It was invented and standardized in 1991 by a group of engineers from the Fraunhofer-Gesellschaft research organization in Erlangen, Germany. MPEG-1 Audio Layer 3, often referred to as MP3, is one of the most popular lossy compression and digital audio encoding formats today. There is no noticeable drop in sound quality compared to the original uncompressed audio. It was invented and standardized in 1991 by a group of engineers from the Fraunhofer-Gesellschaft research organization in Erlangen, Germany. General information MP3 is a data compression format. It discards pulse code modulation (PCM) audio data that is not important to the human ear (similar to how JPEG is lossy image compression), resulting in a much smaller file size. Various techniques are used in MP3, including psychoacoustics, to determine which parts of the audio can be discarded. MP3 audio can be compressed at different bit rates, providing a variety of trade-offs between data size and sound quality. The MP3 format uses a hybrid conversion mechanism to convert the time domain signal to the frequency domain signal: * 32-Band Polyphase Integrating Filter (PQF)
* Modified 36 or 12 tap discrete cosine filter (
MDCT); each subband size is independently selectable between 0…1 and 2…31 However, due to the unprecedented popularity of MP3, the success of any other format is currently unlikely. MP3 not only has extensive client software support, but also has a lot of hardware support, such as portable media players (referring to MP3 players), DVD and CD players.
The development of
MPEG-1 Audio Layer 2 encoding started with the German Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt (later called Deutsches Zentrum für Luft- und Raumfahrt, German Space Center) Digital Audio Broadcasting (DAB) managed by Egon Meier-Project Engelen . This project is funded by the European Union as a EUREKA research project, and its name is commonly known as EU-147. The study period for EU-147 was from 1987 to 1994.
By 1991 there were already two proposals: Musicam (called Layer 2) and ASPEC (Adaptive Spectrum Sensing Entropy Coding). The Musicam method proposed by Philips of the Netherlands, CCETT of France, and the Institut für Rundfunktechnik of Germany was chosen due to its simplicity, robustness against errors, and lower computational effort in high-quality compression. The Musicam format based on subband coding is a key factor in determining the MPEG audio compression format (sampling rate, frame structure, data header, sample points per frame). This technology and its design philosophy are fully integrated into the definition of ISO MPEG Audio Layer I, II and later Layer III (MP3) formats. The standard was developed by Leon van de Kerkhof (Layer I) and Gerhard Stoll (Layer II) under the auspices of Prof. Mussmann (University of Hannover).
A working group consisting of Leon Van de Kerkhof from the Netherlands, Gerhard Stoll from Germany, Yves-François Dehery from France, and Karlheinz Brandenburg from Germany absorbed design ideas from Musicam and ASPEC and added their own design ideas to develop MP3 , which can play MP2. Sound quality from 192kbit/s to 128kbit/s.
All of these algorithms eventually became part of the first group of MPEG standards, MPEG-1, in 1992, resulting in the ISO/IEC 11172-3 international standard published in 1993. Further work on MPEG audio eventually became part of the MPEG-2 standard, a second group of MPEG standards developed in 1994, officially known as ISO/IEC 13818-3, first published in 1995.
The compression efficiency of an encoder is usually defined by the bit rate, since the compression rate depends on the number of bits.
