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Revision as of 00:21, 22 January 2006 by Multimedia Mike (talk | contribs) (added MS and QT identifiers)
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  • Microsoft Audio ID: 0x0055
  • QuickTime FOURCCs: CBR: ('m', 's', 0x00, 0x55); VBR: '.mp3'
  • Patents: US5214678, US5323396, US5777992

Lossy audio coding using a time-frequency transform consisting of a 32-subband polyphase quadrature filter followed by an 18-point MDCT on blocks of 576 samples. In addition, coded frames may be padded by 1 bit as necessary to maintain a strict CBR. This rather odd design was meant to provide backwards compatibility with the blocksize and bit rates of the existing MP2 format. Although it is less efficient than using a pure MDCT (eg AAC and Ogg Vorbis) MP3 has become a de facto standard since it was the first widely available format.