MP3: Difference between revisions
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== Extensions == | |||
== mp3PRO == | === mp3PRO === | ||
mp3PRO is MP3 + [http://www.codingtechnologies.com/products/sbr.htm SBR (Spectral Band Replication)]. (Standard MP3 decoders can decode mp3PRO encoded files/streams but without [http://www.codingtechnologies.com/products/sbr.htm SBR] you do not get the full quality. A [http://www.codingtechnologies.com/products/sbr.htm SBR] decoder could be share code with a aacPlus decoder as aacPlus also uses [http://www.codingtechnologies.com/products/sbr.htm SBR]). | mp3PRO is MP3 + [http://www.codingtechnologies.com/products/sbr.htm SBR (Spectral Band Replication)]. (Standard MP3 decoders can decode mp3PRO encoded files/streams but without [http://www.codingtechnologies.com/products/sbr.htm SBR] you do not get the full quality. A [http://www.codingtechnologies.com/products/sbr.htm SBR] decoder could be share code with a aacPlus decoder as aacPlus also uses [http://www.codingtechnologies.com/products/sbr.htm SBR]). | ||
== XING and VBRI headers == | === XING and VBRI headers === | ||
* See this MPlayer patch: http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2007-March/050609.html | * See this MPlayer patch: http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2007-March/050609.html | ||
== GAIN ([http://mp3gain.sourceforge.net MP3Gain]) header == | === GAIN ([http://mp3gain.sourceforge.net MP3Gain]) header === | ||
There is two versions of this header: one for MP3 and one for [[AAC]]. | There is two versions of this header: one for MP3 and one for [[AAC]]. | ||
[[Category:Audio Codecs]] | [[Category:Audio Codecs]] |
Revision as of 07:06, 6 October 2007
- 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. Each coded frame is padded to a byte boundary. In addition, coded frames may be padded by 1 byte 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 (e.g. AAC and Vorbis) MP3 has become a de facto standard since it was the first widely available format.
Extensions
mp3PRO
mp3PRO is MP3 + SBR (Spectral Band Replication). (Standard MP3 decoders can decode mp3PRO encoded files/streams but without SBR you do not get the full quality. A SBR decoder could be share code with a aacPlus decoder as aacPlus also uses SBR).
XING and VBRI headers
- See this MPlayer patch: http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2007-March/050609.html
GAIN (MP3Gain) header
There is two versions of this header: one for MP3 and one for AAC.