Informal standard                                             M. Nilsson
Document: id3v2-00.txt                                   26th March 1998


                            ID3 tag version 2

Status of this document

   This document is an Informal standard and is released so that
   implementors could have a set standard before the formal standard is
   set. The formal standard will use another version number if not
   identical to what is described in this document. The contents in this
   document may change for clarifications but never for added or altered
   functionallity.

   Distribution of this document is unlimited.


Abstract

   The recent gain of popularity for MPEG layer III audio files on the
   internet forced a standardised way of storing information about an
   audio file within itself to determinate its origin and contents.

   Today the most accepted way to do this is with the so called ID3 tag,
   which is simple but very limited and in some cases very unsuitable.
   The ID3 tag has very limited space in every field, very limited
   numbers of fields, not expandable or upgradeable and is placed at the
   end of a the file, which is unsuitable for streaming audio. This draft
   is an attempt to answer these issues with a new version of the ID3
   tag.


1.   Table of contents

   2.   Conventions in this document
   3.   ID3v2 overview
     3.1.   ID3v2 header
     3.2.   ID3v2 frames overview
   4.   Declared ID3v2 frames
     4.1.   Unique file identifier
     4.2.   Text information frames
       4.2.1.   Text information frames - details
       4.2.2.   User defined text information frame
     4.3.   URL link frames
       4.3.1.   URL link frames - details
       4.3.2.   User defined URL link frame
     4.4.   Involved people list
     4.5.   Music CD Identifier
     4.6.   Event timing codes
     4.7.   MPEG location lookup table
     4.8.   Synced tempo codes
     4.9.   Unsychronised lyrics/text transcription
     4.10.  Synchronised lyrics/text
     4.11.  Comments
     4.12.  Relative volume adjustment
     4.13.  Equalisation
     4.14.  Reverb
     4.15.  Attached picture
     4.16.  General encapsulated object
     4.17.  Play counter
     4.18.  Popularimeter
     4.19.  Recommended buffer size
     4.20.  Encrypted meta frame
     4.21.  Audio encryption
     4.22.  Linked information
   5.   The 'unsynchronisation scheme'
   6.   Copyright
   7.   References
   8.   Appendix
     A.   Appendix A - ID3-Tag Specification V1.1
       A.1.   Overview
       A.2.   ID3v1 Implementation
       A.3.   Genre List
       A.4.   Track addition - ID3v1.1
   9.   Author's Address


2.   Conventions in this document

   In the examples, text within "" is a text string exactly as it appears
   in a file. Numbers preceded with $ are hexadecimal and numbers
   preceded with % are binary. $xx is used to indicate a byte with
   unknown content. %x is used to indicate a bit with unknown content.
   The most significant bit (MSB) of a byte is called 'bit 7' and the
   least significant bit (LSB) is called 'bit 0'.

   A tag is the whole tag described in this document. A frame is a block
   of information in the tag. The tag consists of a header, frames and
   optional padding. A field is a piece of information; one value, a
   string etc. A numeric string is a string that consists of the
   characters 0-9 only.


3.   ID3v2 overview

   The two biggest design goals were to be able to implement ID3v2
   without disturbing old software too much and that ID3v2 should be
   expandable.

   The first criterion is met by the simple fact that the MPEG [MPEG]
   decoding software uses a syncsignal, embedded in the audiostream, to
   'lock on to' the audio. Since the ID3v2 tag doesn't contain a valid
   syncsignal, no software will attempt to play the tag. If, for any
   reason, coincidence make a syncsignal appear within the tag it will be
   taken care of by the 'unsynchronisation scheme' described in section
   5.

   The second criterion has made a more noticeable impact on the design
   of the ID3v2 tag. It is constructed as a container for several
   information blocks, called frames, whose format need not be known to
   the software that encounters them. At the start of every frame there
   is an identifier that explains the frames's format and content, and a
   size descriptor that allows software to skip unknown frames.

   If a total revision of the ID3v2 tag should be needed, there is a
   version number and a size descriptor in the ID3v2 header.

   The ID3 tag described in this document is mainly targeted to files
   encoded with MPEG-2 layer I, MPEG-2 layer II, MPEG-2 layer III and
   MPEG-2.5, but may work with other types of encoded audio.

   The bitorder in ID3v2 is most significant bit first (MSB). The
   byteorder in multibyte numbers is most significant byte first (e.g.
   $12345678 would be encoded $12 34 56 78).

   It is permitted to include padding after all the final frame (at the
   end of the ID3 tag), making the size of all the frames together
   smaller than the size given in the head of the tag. A possible purpose
   of this padding is to allow for adding a few additional frames or
   enlarge existing frames within the tag without having to rewrite the
   entire file. The value of the padding bytes must be $00.


3.1.   ID3v2 header

   The ID3v2 tag header, which should be the first information in the
   file, is 10 bytes as follows:

     ID3/file identifier      "ID3"
     ID3 version              $02 00
     ID3 flags                %xx000000
     ID3 size             4 * %0xxxxxxx

   The first three bytes of the tag are always "ID3" to indicate that
   this is an ID3 tag, directly followed by the two version bytes. The
   first byte of ID3 version is it's major version, while the second byte
   is its revision number. All revisions are backwards compatible while
   major versions are not. If software with ID3v2 and below support
   should encounter version three or higher it should simply ignore the
   whole tag. Version and revision will never be $FF.

   The first bit (bit 7) in the 'ID3 flags' is indicating whether or not
   unsynchronisation is used (see section 5 for details); a set bit
   indicates usage.

   The second bit (bit 6) is indicating whether or not compression is
   used; a set bit indicates usage. Since no compression scheme has been
   decided yet, the ID3 decoder (for now) should just ignore the entire
   tag if the compression bit is set.

   The ID3 tag size is encoded with four bytes where the first bit (bit
   7) is set to zero in every byte, making a total of 28 bits. The zeroed
   bits are ignored, so a 257 bytes long tag is represented as $00 00 02
   01.

   The ID3 tag size is the size of the complete tag after
   unsychronisation, including padding, excluding the header (total tag
   size - 10). The reason to use 28 bits (representing up to 256MB) for
   size description is that we don't want to run out of space here.

   A ID3v2 tag can be detected with the following pattern:
     $49 44 33 yy yy xx zz zz zz zz
   Where yy is less than $FF, xx is the 'flags' byte and zz is less than
   $80.


3.2.   ID3v2 frames overview

   The headers of the frames are similar in their construction. They
   consist of one three character identifier (capital A-Z and 0-9) and
   one three byte size field, making a total of six bytes. The header is
   excluded from the size. Identifiers beginning with "X", "Y" and "Z"
   are for experimental use and free for everyone to use. Have in mind
   that someone else might have used the same identifier as you. All
   other identifiers are either used or reserved for future use.

   The three character frame identifier is followed by a three byte size
   descriptor, making a total header size of six bytes in every frame.
   The size is calculated as framesize excluding frame identifier and
   size descriptor (frame size - 6).

   There is no fixed order of the frames' appearance in the tag, although
   it is desired that the frames are arranged in order of significance
   concerning the recognition of the file. An example of such order:
   UFI, MCI, TT2 ...

   A tag must contain at least one frame. A frame must be at least 1 byte
   big, excluding the 6-byte header.

   If nothing else is said a string is represented as ISO-8859-1
   [ISO-8859-1] characters in the range $20 - $FF. All unicode strings
   [UNICODE] use 16-bit unicode 2.0 (ISO/IEC 10646-1:1993, UCS-2). All
   numeric strings are always encoded as ISO-8859-1. Terminated strings
   are terminated with $00 if encoded with ISO-8859-1 and $00 00 if
   encoded as unicode. If nothing else is said newline character is
   forbidden. In ISO-8859-1 a new line is represented, when allowed, with
   $0A only. Frames that allow different types of text encoding have a
   text encoding description byte directly after the frame size. If
   ISO-8859-1 is used this byte should be $00, if unicode is used it
   should be $01.

   The three byte language field is used to describe the language of the
   frame's content, according to ISO-639-2 [ISO-639-2].

   All URLs [URL] may be relative, e.g. "picture.png", "../doc.txt".

   If a frame is longer than it should be, e.g. having more fields than
   specified in this document, that indicates that additions to the
   frame have been made in a later version of the ID3 standard. This
   is reflected by the revision number in the header of the tag.


4.   Declared ID3v2 frames

   The following frames are declared in this draft.

   4.19  BUF Recommended buffer size

   4.17  CNT Play counter
   4.11  COM Comments
   4.21  CRA Audio encryption
   4.20  CRM Encrypted meta frame

   4.6   ETC Event timing codes
   4.13  EQU Equalization

   4.16  GEO General encapsulated object

   4.4   IPL Involved people list

   4.22  LNK Linked information

   4.5   MCI Music CD Identifier
   4.7   MLL MPEG location lookup table

   4.15  PIC Attached picture
   4.18  POP Popularimeter

   4.14  REV Reverb
   4.12  RVA Relative volume adjustment

   4.10  SLT Synchronized lyric/text
   4.8   STC Synced tempo codes

   4.2.1 TAL Album/Movie/Show title
   4.2.1 TBP BPM (Beats Per Minute)
   4.2.1 TCM Composer
   4.2.1 TCO Content type
   4.2.1 TCR Copyright message
   4.2.1 TDA Date
   4.2.1 TDY Playlist delay
   4.2.1 TEN Encoded by
   4.2.1 TFT File type
   4.2.1 TIM Time
   4.2.1 TKE Initial key
   4.2.1 TLA Language(s)
   4.2.1 TLE Length
   4.2.1 TMT Media type
   4.2.1 TOA Original artist(s)/performer(s)
   4.2.1 TOF Original filename
   4.2.1 TOL Original Lyricist(s)/text writer(s)
   4.2.1 TOR Original release year
   4.2.1 TOT Original album/Movie/Show title
   4.2.1 TP1 Lead artist(s)/Lead performer(s)/Soloist(s)/Performing group
   4.2.1 TP2 Band/Orchestra/Accompaniment
   4.2.1 TP3 Conductor/Performer refinement
   4.2.1 TP4 Interpreted, remixed, or otherwise modified by
   4.2.1 TPA Part of a set
   4.2.1 TPB Publisher
   4.2.1 TRC ISRC (International Standard Recording Code)
   4.2.1 TRD Recording dates
   4.2.1 TRK Track number/Position in set
   4.2.1 TSI Size
   4.2.1 TSS Software/hardware and settings used for encoding
   4.2.1 TT1 Content group description
   4.2.1 TT2 Title/Songname/Content description
   4.2.1 TT3 Subtitle/Description refinement
   4.2.1 TXT Lyricist/text writer
   4.2.2 TXX User defined text information frame
   4.2.1 TYE Year

   4.1   UFI Unique file identifier
   4.9   ULT Unsychronized lyric/text transcription

   4.3.1 WAF Official audio file webpage
   4.3.1 WAR Official artist/performer webpage
   4.3.1 WAS Official audio source webpage
   4.3.1 WCM Commercial information
   4.3.1 WCP Copyright/Legal information
   4.3.1 WPB Publishers official webpage
   4.3.2 WXX User defined URL link frame


4.1.   Unique file identifier

   This frame's purpose is to be able to identify the audio file in a
   database that may contain more information relevant to the content.
   Since standardisation of such a database is beyond this document, all
   frames begin with a null-terminated string with a URL [URL] containing
   an email address, or a link to a location where an email address can
   be found, that belongs to the organisation responsible for this
   specific database implementation. Questions regarding the database
   should be sent to the indicated email address. The URL should not be
   used for the actual database queries. If a $00 is found directly after
   the 'Frame size' the whole frame should be ignored, and preferably be
   removed. The 'Owner identifier' is then followed by the actual
   identifier, which may be up to 64 bytes. There may be more than one
   "UFI" frame in a tag, but only one with the same 'Owner identifier'.

     Unique file identifier  "UFI"
     Frame size              $xx xx xx
     Owner identifier        <textstring> $00
     Identifier              <up to 64 bytes binary data>


4.2.   Text information frames

   The text information frames are the most important frames, containing
   information like artist, album and more. There may only be one text
   information frame of its kind in an tag. If the textstring is followed
   by a termination ($00 (00)) all the following information should be
   ignored and not be displayed. All the text information frames have the
   following format:

     Text information identifier  "T00" - "TZZ" , excluding "TXX",
                                   described in 4.2.2.
     Frame size                   $xx xx xx
     Text encoding                $xx
     Information                  <textstring>


4.2.1.   Text information frames - details

  TT1
   The 'Content group description' frame is used if the sound belongs to
   a larger category of sounds/music. For example, classical music is
   often sorted in different musical sections (e.g. "Piano Concerto",
   "Weather - Hurricane").

  TT2
   The 'Title/Songname/Content description' frame is the actual name of
   the piece (e.g. "Adagio", "Hurricane Donna").

  TT3
   The 'Subtitle/Description refinement' frame is used for information
   directly related to the contents title (e.g. "Op. 16" or "Performed
   live at wembley").

  TP1
   The 'Lead artist(s)/Lead performer(s)/Soloist(s)/Performing group' is
   used for the main artist(s). They are seperated with the "/"
   character.

  TP2
   The 'Band/Orchestra/Accompaniment' frame is used for additional
   information about the performers in the recording.

  TP3
   The 'Conductor' frame is used for the name of the conductor.
   
  TP4
   The 'Interpreted, remixed, or otherwise modified by' frame contains
   more information about the people behind a remix and similar
   interpretations of another existing piece.

  TCM
   The 'Composer(s)' frame is intended for the name of the composer(s).
   They are seperated with the "/" character.

  TXT
   The 'Lyricist(s)/text writer(s)' frame is intended for the writer(s)
   of the text or lyrics in the recording. They are seperated with the
   "/" character.

  TLA
   The 'Language(s)' frame should contain the languages of the text or
   lyrics in the audio file. The language is represented with three
   characters according to ISO-639-2. If more than one language is used
   in the text their language codes should follow according to their
   usage.

  TCO
   The content type, which previously (in ID3v1.1, see appendix A) was
   stored as a one byte numeric value only, is now a numeric string. You
   may use one or several of the types as ID3v1.1 did or, since the
   category list would be impossible to maintain with accurate and up to
   date categories, define your own.
   References to the ID3v1 genres can be made by, as first byte, enter
   "(" followed by a number from the genres list (section A.3.) and
   ended with a ")" character. This is optionally followed by a
   refinement, e.g. "(21)" or "(4)Eurodisco". Several references can be
   made in the same frame, e.g. "(51)(39)". If the refinement should
   begin with a "(" character it should be replaced with "((", e.g. "((I
   can figure out any genre)" or "(55)((I think...)". The following new
   content types is defined in ID3v2 and is implemented in the same way
   as the numerig content types, e.g. "(RX)".
   
     RX  Remix
     CR  Cover

  TAL
   The 'Album/Movie/Show title' frame is intended for the title of the
   recording(/source of sound) which the audio in the file is taken from.
   
  TPA
   The 'Part of a set' frame is a numeric string that describes which
   part of a set the audio came from. This frame is used if the source
   described in the "TAL" frame is divided into several mediums, e.g. a
   double CD. The value may be extended with a "/" character and a
   numeric string containing the total number of parts in the set. E.g.
   "1/2".

  TRK
   The 'Track number/Position in set' frame is a numeric string
   containing the order number of the audio-file on its original
   recording. This may be extended with a "/" character and a numeric
   string containing the total numer of tracks/elements on the original
   recording. E.g. "4/9".

  TRC
   The 'ISRC' frame should contian the International Standard Recording
   Code [ISRC].

  TYE
   The 'Year' frame is a numeric string with a year of the recording.
   This frames is always four characters long (until the year 10000).

  TDA
   The 'Date' frame is a numeric string in the DDMM format containing
   the date for the recording. This field is always four characters
   long.

  TIM
   The 'Time' frame is a numeric string in the HHMM format containing
   the time for the recording. This field is always four characters
   long.
   
  TRD
   The 'Recording dates' frame is a intended to be used as complement to
   the "TYE", "TDA" and "TIM" frames. E.g. "4th-7th June, 12th June" in
   combination with the "TYE" frame.

  TMT
   The 'Media type' frame describes from which media the sound
   originated. This may be a textstring or a reference to the predefined
   media types found in the list below. References are made within "("
   and ")" and are optionally followed by a text refinement, e.g. "(MC)
   with four channels". If a text refinement should begin with a "("
   character it should be replaced with "((" in the same way as in the
   "TCO" frame. Predefined refinements is appended after the media type,
   e.g. "(CD/S)" or "(VID/PAL/VHS)".

    DIG    Other digital media
      /A    Analog transfer from media

    ANA    Other analog media
      /WAC  Wax cylinder
      /8CA  8-track tape cassette

    CD     CD
      /A    Analog transfer from media
      /DD   DDD
      /AD   ADD
      /AA   AAD

    LD     Laserdisc
      /A     Analog transfer from media

    TT     Turntable records
      /33    33.33 rpm
      /45    45 rpm
      /71    71.29 rpm
      /76    76.59 rpm
      /78    78.26 rpm
      /80    80 rpm
     
    MD     MiniDisc
      /A    Analog transfer from media
     
    DAT    DAT
      /A    Analog transfer from media
      /1    standard, 48 kHz/16 bits, linear
      /2    mode 2, 32 kHz/16 bits, linear
      /3    mode 3, 32 kHz/12 bits, nonlinear, low speed
      /4    mode 4, 32 kHz/12 bits, 4 channels
      /5    mode 5, 44.1 kHz/16 bits, linear
      /6    mode 6, 44.1 kHz/16 bits, 'wide track' play
     
    DCC    DCC
      /A    Analog transfer from media
    
    DVD    DVD
      /A    Analog transfer from media
    
    TV     Television
      /PAL    PAL
      /NTSC   NTSC
      /SECAM  SECAM
    
    VID    Video
      /PAL    PAL
      /NTSC   NTSC
      /SECAM  SECAM
      /VHS    VHS
      /SVHS   S-VHS
      /BETA   BETAMAX
    
    RAD    Radio
      /FM   FM
      /AM   AM
      /LW   LW
      /MW   MW
    
    TEL    Telephone
      /I    ISDN
    
    MC     MC (normal cassette)
      /4    4.75 cm/s (normal speed for a two sided cassette)
      /9    9.5 cm/s
      /I    Type I cassette (ferric/normal)
      /II   Type II cassette (chrome)
      /III  Type III cassette (ferric chrome)
      /IV   Type IV cassette (metal)
    
    REE    Reel
      /9    9.5 cm/s
      /19   19 cm/s
      /38   38 cm/s
      /76   76 cm/s
      /I    Type I cassette (ferric/normal)
      /II   Type II cassette (chrome)
      /III  Type III cassette (ferric chrome)
      /IV   Type IV cassette (metal)

  TFT
   The 'File type' frame indicates which type of audio this tag defines.
   The following type and refinements are defined:
   
     MPG    MPEG Audio
       /1     MPEG 2 layer I
       /2     MPEG 2 layer II
       /3     MPEG 2 layer III
       /2.5   MPEG 2.5
       /AAC   Advanced audio compression
     
   but other types may be used, not for these types though. This is used
   in a similar way to the predefined types in the "TMT" frame, but
   without parenthesis. If this frame is not present audio type is
   assumed to be "MPG".

  TBP
   BPM is short for beats per minute, and is easily computed by
   dividing the number of beats in a musical piece with its length. To
   get a more accurate result, do the BPM calculation on the main-part
   only. To acquire best result measure the time between each beat and
   calculate individual BPM for each beat and use the median value as
   result. BPM is an integer and represented as a numerical string.

  TCR
   The 'Copyright message' frame, which must begin with a year and a
   space character (making five characters), is intended for the
   copyright holder of the original sound, not the audio file itself. The
   absence of this frame means only that the copyright information is
   unavailable or has been removed, and must not be interpreted to mean
   that the sound is public domain. Every time this field is displayed
   the field must be preceded with "Copyright " (C) " ", where (C) is one
   character showing a C in a circle.

  TPB
   The 'Publisher' frame simply contains the name of the label or
   publisher.

  TEN
   The 'Encoded by' frame contains the name of the person or
   organisation that encoded the audio file. This field may contain a
   copyright message, if the audio file also is copyrighted by the
   encoder.

  TSS
   The 'Software/hardware and settings used for encoding' frame
   includes the used audio encoder and its settings when the file was
   encoded. Hardware refers to hardware encoders, not the computer on
   which a program was run.

  TOF
   The 'Original filename' frame contains the preferred filename for the
   file, since some media doesn't allow the desired length of the
   filename. The filename is case sensitive and includes its suffix.

  TLE
   The 'Length' frame contains the length of the audiofile in
   milliseconds, represented as a numeric string.

  TSI
   The 'Size' frame contains the size of the audiofile in bytes
   excluding the tag, represented as a numeric string.

  TDY
   The 'Playlist delay' defines the numbers of milliseconds of silence
   between every song in a playlist. The player should use the "ETC"
   frame, if present, to skip initial silence and silence at the end of
   the audio to match the 'Playlist delay' time. The time is represented
   as a numeric string.

  TKE
   The 'Initial key' frame contains the musical key in which the sound
   starts. It is represented as a string with a maximum length of three
   characters. The ground keys are represented with "A","B","C","D","E",
   "F" and "G" and halfkeys represented with "b" and "#". Minor is
   represented as "m". Example "Cbm". Off key is represented with an "o"
   only.

  TOT
   The 'Original album/Movie/Show title' frame is intended for the title
   of the original recording(/source of sound), if for example the music
   in the file should be a cover of a previously released song.
   
  TOA
   The 'Original artist(s)/performer(s)' frame is intended for the
   performer(s) of the original recording, if for example the music in
   the file should be a cover of a previously released song. The
   performers are seperated with the "/" character.

  TOL
   The 'Original Lyricist(s)/text writer(s)' frame is intended for the
   text writer(s) of the original recording, if for example the music in
   the file should be a cover of a previously released song. The text
   writers are seperated with the "/" character.

  TOR
   The 'Original release year' frame is intended for the year when the
   original recording, if for example the music in the file should be a
   cover of a previously released song, was released. The field is
   formatted as in the "TDY" frame.


4.2.2.   User defined text information frame

   This frame is intended for one-string text information concerning the
   audiofile in a similar way to the other "T"xx frames. The frame body
   consists of a description of the string, represented as a terminated
   string, followed by the actual string. There may be more than one
   "TXX" frame in each tag, but only one with the same description.

     User defined...   "TXX"
     Frame size        $xx xx xx
     Text encoding     $xx
     Description       <textstring> $00 (00)
     Value             <textstring>


4.3.   URL link frames

   With these frames dynamic data such as webpages with touring
   information, price information or plain ordinary news can be added to
   the tag. There may only be one URL [URL] link frame of its kind in an
   tag, except when stated otherwise in the frame description. If the
   textstring is followed by a termination ($00 (00)) all the following
   information should be ignored and not be displayed. All URL link
   frames have the following format:

     URL link frame   "W00" - "WZZ" , excluding "WXX" 
                                      (described in 4.3.2.)
     Frame size       $xx xx xx
     URL              <textstring>


4.3.1.   URL link frames - details

  WAF
   The 'Official audio file webpage' frame is a URL pointing at a file
   specific webpage.
   
  WAR
   The 'Official artist/performer webpage' frame is a URL pointing at
   the artists official webpage. There may be more than one "WAR" frame
   in a tag if the audio contains more than one performer.
   
  WAS
   The 'Official audio source webpage' frame is a URL pointing at the
   official webpage for the source of the audio file, e.g. a movie.
   
  WCM
   The 'Commercial information' frame is a URL pointing at a webpage
   with information such as where the album can be bought. There may be
   more than one "WCM" frame in a tag.
   
  WCP
   The 'Copyright/Legal information' frame is a URL pointing at a
   webpage where the terms of use and ownership of the file is described.
   
  WPB
   The 'Publishers official webpage' frame is a URL pointing at the
   official wepage for the publisher.


4.3.2.   User defined URL link frame

   This frame is intended for URL [URL] links concerning the audiofile in
   a similar way to the other "W"xx frames. The frame body consists of a
   description of the string, represented as a terminated string,
   followed by the actual URL. The URL is always encoded with ISO-8859-1
   [ISO-8859-1]. There may be more than one "WXX" frame in each tag, but
   only one with the same description.

     User defined...   "WXX"
     Frame size        $xx xx xx
     Text encoding     $xx
     Description       <textstring> $00 (00)
     URL               <textstring>


4.4.   Involved people list

   Since there might be a lot of people contributing to an audio file in
   various ways, such as musicians and technicians, the 'Text
   information frames' are often insufficient to list everyone involved
   in a project. The 'Involved people list' is a frame containing the
   names of those involved, and how they were involved. The body simply
   contains a terminated string with the involvement directly followed by
   a terminated string with the involvee followed by a new involvement
   and so on. There may only be one "IPL" frame in each tag.

     Involved people list   "IPL"
     Frame size             $xx xx xx
     Text encoding          $xx
     People list strings    <textstrings>


4.5.   Music CD Identifier

   This frame is intended for music that comes from a CD, so that the CD
   can be identified in databases such as the CDDB [CDDB]. The frame
   consists of a binary dump of the Table Of Contents, TOC,  from the CD,
   which is a header of 4 bytes and then 8 bytes/track on the CD making a
   maximum of 804 bytes. This frame requires a present and valid "TRK"
   frame. There may only be one "MCI" frame in each tag.

     Music CD identifier   "MCI"
     Frame size            $xx xx xx
     CD TOC                <binary data>


4.6.   Event timing codes

   This frame allows synchronisation with key events in a song or sound.
   The head is:

     Event timing codes   "ETC"
     Frame size           $xx xx xx
     Time stamp format    $xx
     
   Where time stamp format is:
     
     $01  Absolute time, 32 bit sized, using MPEG [MPEG] frames as unit
     $02  Absolute time, 32 bit sized, using milliseconds as unit

   Abolute time means that every stamp contains the time from the
   beginning of the file.

   Followed by a list of key events in the following format:

     Type of event   $xx
     Time stamp      $xx (xx ...)

   The 'Time stamp' is set to zero if directly at the beginning of the
   sound or after the previous event. All events should be sorted in
   chronological order. The type of event is as follows:

     $00  padding (has no meaning)
     $01  end of initial silence
     $02  intro start
     $03  mainpart start
     $04  outro start
     $05  outro end
     $06  verse begins
     $07  refrain begins
     $08  interlude
     $09  theme start
     $0A  variation
     $0B  key change
     $0C  time change
     $0D  unwanted noise (Snap, Crackle & Pop)

     $0E-$DF  reserved for future use

     $E0-$EF  not predefined sync 0-F

     $F0-$FC  reserved for future use

     $FD  audio end (start of silence)
     $FE  audio file ends
     $FF  one more byte of events follows (all the following bytes with
          the value $FF have the same function)

   The 'Not predefined sync's ($E0-EF) are for user events. You might
   want to synchronise your music to something, like setting of an
   explosion on-stage, turning on your screensaver etc.

   There may only be one "ETC" frame in each tag.


4.7.   MPEG location lookup table

   To increase performance and accuracy of jumps within a MPEG [MPEG]
   audio file, frames with timecodes in different locations in the file
   might be useful. The ID3 frame includes references that the software
   can use to calculate positions in the file. After the frame header is
   a descriptor of how much the 'frame counter' should increase for every
   reference. If this value is two then the first reference points out
   the second frame, the 2nd reference the 4th frame, the 3rd reference
   the 6th frame etc. In a similar way the 'bytes between reference' and
   'milliseconds between reference' points out bytes and milliseconds
   respectively.
   
   Each reference consists of two parts; a certain number of bits, as
   defined in 'bits for bytes deviation', that describes the difference
   between what is said in 'bytes between reference' and the reality and
   a certain number of bits, as defined in 'bits for milliseconds
   deviation', that describes the difference between what is said in
   'milliseconds between reference' and the reality. The number of bits
   in every reference, i.e. 'bits for bytes deviation'+'bits for
   milliseconds deviation', must be a multiple of four. There may only be
   one "MLL" frame in each tag.
   
     Location lookup table          "MLL"
     ID3 frame size                 $xx xx xx
     MPEG frames between reference  $xx xx
     Bytes between reference        $xx xx xx
     Milliseconds between reference $xx xx xx
     Bits for bytes deviation       $xx
     Bits for milliseconds dev.     $xx

   Then for every reference the following data is included;

     Deviation in bytes         %xxx....
     Deviation in milliseconds  %xxx....


4.8.   Synced tempo codes

   For a more accurate description of the tempo of a musical piece this
   frame might be used. After the header follows one byte describing
   which time stamp format should be used. Then follows one or more tempo
   codes. Each tempo code consists of one tempo part and one time part.
   The tempo is in BPM described with one or two bytes. If the first byte
   has the value $FF, one more byte follows, which is added to the first
   giving a range from 2 - 510 BPM, since $00 and $01 is reserved. $00 is
   used to describe a beat-free time period, which is not the same as a
   music-free time period. $01 is used to indicate one single beat-stroke
   followed by a beat-free period.

   The tempo descriptor is followed by a time stamp. Every time the tempo
   in the music changes, a tempo descriptor may indicate this for the
   player. All tempo descriptors should be sorted in chronological order.
   The first beat-stroke in a time-period is at the same time as the beat
   description occurs. There may only be one "STC" frame in each tag.

     Synced tempo codes  "STC"
     Frame size          $xx xx xx
     Time stamp format   $xx
     Tempo data          <binary data>

   Where time stamp format is:
     
     $01  Absolute time, 32 bit sized, using MPEG [MPEG] frames as unit
     $02  Absolute time, 32 bit sized, using milliseconds as unit

   Abolute time means that every stamp contains the time from the
   beginning of the file.


4.9.   Unsychronised lyrics/text transcription

   This frame contains the lyrics of the song or a text transcription of
   other vocal activities. The head includes an encoding descriptor and
   a content descriptor. The body consists of the actual text. The
   'Content descriptor' is a terminated string. If no descriptor is
   entered, 'Content descriptor' is $00 (00) only. Newline characters
   are allowed in the text. Maximum length for the descriptor is 64
   bytes. There may be more than one lyrics/text frame in each tag, but
   only one with the same language and content descriptor.

     Unsynced lyrics/text "ULT"
     Frame size           $xx xx xx
     Text encoding        $xx
     Language             $xx xx xx
     Content descriptor   <textstring> $00 (00)
     Lyrics/text          <textstring>


4.10.   Synchronised lyrics/text

   This is another way of incorporating the words, said or sung lyrics,
   in the audio file as text, this time, however, in sync with the audio.
   It might also be used to describing events e.g. occurring on a stage
   or on the screen in sync with the audio. The header includes a content
   descriptor, represented with as terminated textstring. If no
   descriptor is entered, 'Content descriptor' is $00 (00) only.

     Synced lyrics/text   "SLT"
     Frame size           $xx xx xx
     Text encoding        $xx
     Language             $xx xx xx
     Time stamp format    $xx
     Content type         $xx
     Content descriptor   <textstring> $00 (00)


   Encoding:   $00  ISO-8859-1 [ISO-8859-1] character set is used => $00
                    is sync identifier.
               $01  Unicode [UNICODE] character set is used => $00 00 is
                    sync identifier.

   Content type:   $00 is other
                   $01 is lyrics
                   $02 is text transcription
                   $03 is movement/part name (e.g. "Adagio")
                   $04 is events (e.g. "Don Quijote enters the stage")
                   $05 is chord (e.g. "Bb F Fsus")

   Time stamp format is:
     
     $01  Absolute time, 32 bit sized, using MPEG [MPEG] frames as unit
     $02  Absolute time, 32 bit sized, using milliseconds as unit

   Abolute time means that every stamp contains the time from the
   beginning of the file.

   The text that follows the frame header differs from that of the
   unsynchronised lyrics/text transcription in one major way. Each
   syllable (or whatever size of text is considered to be convenient by
   the encoder) is a null terminated string followed by a time stamp
   denoting where in the sound file it belongs. Each sync thus has the
   following structure:

     Terminated text to be synced (typically a syllable)
     Sync identifier (terminator to above string)   $00 (00)
     Time stamp                                     $xx (xx ...)

   The 'time stamp' is set to zero or the whole sync is omitted if
   located directly at the beginning of the sound. All time stamps should
   be sorted in chronological order. The sync can be considered as a
   validator of the subsequent string.

   Newline characters are allowed in all "SLT" frames and should be used
   after every entry (name, event etc.) in a frame with the content type
   $03 - $04.

   A few considerations regarding whitespace characters: Whitespace
   separating words should mark the beginning of a new word, thus
   occurring in front of the first syllable of a new word. This is also
   valid for new line characters. A syllable followed by a comma should
   not be broken apart with a sync (both the syllable and the comma
   should be before the sync).

   An example: The "ULT" passage

     "Strangers in the night" $0A "Exchanging glances"

   would be "SLT" encoded as:

     "Strang" $00 xx xx "ers" $00 xx xx " in" $00 xx xx " the" $00 xx xx
     " night" $00 xx xx 0A "Ex" $00 xx xx "chang" $00 xx xx "ing" $00 xx
     xx "glan" $00 xx xx "ces" $00 xx xx

   There may be more than one "SLT" frame in each tag, but only one with
   the same language and content descriptor.


4.11.   Comments

   This frame replaces the old 30-character comment field in ID3v1. It
   consists of a frame head followed by encoding, language and content
   descriptors and is ended with the actual comment as a text string.
   Newline characters are allowed in the comment text string. There may
   be more than one comment frame in each tag, but only one with the same
   language and content descriptor.

     Comment                   "COM"
     Frame size                $xx xx xx
     Text encoding             $xx
     Language                  $xx xx xx
     Short content description <textstring> $00 (00)
     The actual text           <textstring>


4.12.   Relative volume adjustment

   This is a more subjective function than the previous ones. It allows
   the user to say how much he wants to increase/decrease the volume on
   each channel while the file is played. The purpose is to be able to
   align all files to a reference volume, so that you don't have to
   change the volume constantly. This frame may also be used to balance
   adjust the audio. If the volume peak levels are known then this could
   be described with the 'Peak volume right' and 'Peak volume left'
   field. If Peakvolume is not known these fields could be left zeroed
   or completely omitted.  There may only be one "RVA" frame in each
   tag.

     Relative volume adjustment    "RVA"
     Frame size                    $xx xx xx
     Increment/decrement           %000000xx
     Bits used for volume descr.   $xx
     Relative volume change, right $xx xx (xx ...)
     Relative volume change, left  $xx xx (xx ...)
     Peak volume right             $xx xx (xx ...)
     Peak volume left              $xx xx (xx ...)

   In the increment/decrement field bit 0 is used to indicate the right
   channel and bit 1 is used to indicate the left channel. 1 is
   increment and 0 is decrement.

   The 'bits used for volume description' field is normally $10 (16 bits)
   for MPEG 2 layer I, II and III [MPEG] and MPEG 2.5. This value may not
   be $00. The volume is always represented with whole bytes, padded in
   the beginning (highest bits) when 'bits used for volume description'
   is not a multiple of eight.


4.13.   Equalisation

   This is another subjective, alignment frame. It allows the user to
   predefine an equalisation curve within the audio file. There may only
   be one "EQU" frame in each tag.

     Equalisation       "EQU"
     Frame size         $xx xx xx
     Adjustment bits    $xx

   The 'adjustment bits' field defines the number of bits used for
   representation of the adjustment. This is normally $10 (16 bits) for
   MPEG 2 layer I, II and III [MPEG] and MPEG 2.5. This value may not be
   $00.

   This is followed by 2 bytes + ('adjustment bits' rounded up to the
   nearest byte) for every equalisation band in the following format,
   giving a frequency range of 0 - 32767Hz:

     Increment/decrement   %x (MSB of the Frequency)
     Frequency             (lower 15 bits)
     Adjustment            $xx (xx ...)

   The increment/decrement bit is 1 for increment and 0 for decrement.
   The equalisation bands should be ordered increasingly with reference
   to frequency. All frequencies don't have to be declared. Adjustments
   with the value $00 should be omitted. A frequency should only be
   described once in the frame.


4.14.   Reverb

   Yet another subjective one. You may here adjust echoes of different
   kinds. Reverb left/right is the delay between every bounce in ms.
   Reverb bounces left/right is the number of bounces that should be
   made. $FF equals an infinite number of bounces. Feedback is the amount
   of volume that should be returned to the next echo bounce. $00 is 0%,
   $FF is 100%. If this value were $7F, there would be 50% volume
   reduction on the first bounce, yet 50% on the second and so on. Left
   to left means the sound from the left bounce to be played in the left
   speaker, while left to right means sound from the left bounce to be
   played in the right speaker.

   'Premix left to right' is the amount of left sound to be mixed in the
   right before any reverb is applied, where $00 id 0% and $FF is 100%.
   'Premix right to left' does the same thing, but right to left. Setting
   both premix to $FF would result in a mono output (if the reverb is
   applied symmetric). There may only be one "REV" frame in each tag.

     Reverb settings                  "REV"
     Frame size                       $00 00 0C
     Reverb left (ms)                 $xx xx
     Reverb right (ms)                $xx xx
     Reverb bounces, left             $xx
     Reverb bounces, right            $xx
     Reverb feedback, left to left    $xx
     Reverb feedback, left to right   $xx
     Reverb feedback, right to right  $xx
     Reverb feedback, right to left   $xx
     Premix left to right             $xx
     Premix right to left             $xx


4.15.   Attached picture

   This frame contains a picture directly related to the audio file.
   Image format is preferably "PNG" [PNG] or "JPG" [JFIF]. Description
   is a short description of the picture, represented as a terminated
   textstring. The description has a maximum length of 64 characters,
   but may be empty. There may be several pictures attached to one file,
   each in their individual "PIC" frame, but only one with the same
   content descriptor. There may only be one picture with the picture
   type declared as picture type $01 and $02 respectively. There is a
   possibility to put only a link to the image file by using the 'image
   format' "-->" and having a complete URL [URL] instead of picture data.
   The use of linked files should however be used restrictively since
   there is the risk of separation of files.

     Attached picture   "PIC"
     Frame size         $xx xx xx
     Text encoding      $xx
     Image format       $xx xx xx
     Picture type       $xx
     Description        <textstring> $00 (00)
     Picture data       <binary data>


   Picture type:  $00  Other
                  $01  32x32 pixels 'file icon' (PNG only)
                  $02  Other file icon
                  $03  Cover (front)
                  $04  Cover (back)
                  $05  Leaflet page
                  $06  Media (e.g. lable side of CD)
                  $07  Lead artist/lead performer/soloist
                  $08  Artist/performer
                  $09  Conductor
                  $0A  Band/Orchestra
                  $0B  Composer
                  $0C  Lyricist/text writer
                  $0D  Recording Location
                  $0E  During recording
                  $0F  During performance
                  $10  Movie/video screen capture
                  $11  A bright coloured fish
                  $12  Illustration
                  $13  Band/artist logotype
                  $14  Publisher/Studio logotype


4.16.   General encapsulated object

   In this frame any type of file can be encapsulated. After the header,
   'Frame size' and 'Encoding' follows 'MIME type' [MIME] and 'Filename'
   for the encapsulated object, both represented as terminated strings
   encoded with ISO 8859-1 [ISO-8859-1]. The filename is case sensitive.
   Then follows a content description as terminated string, encoded as
   'Encoding'. The last thing in the frame is the actual object. The
   first two strings may be omitted, leaving only their terminations.
   MIME type is always an ISO-8859-1 text string. There may be more than
   one "GEO" frame in each tag, but only one with the same content
   descriptor.

     General encapsulated object "GEO"
     Frame size                  $xx xx xx
     Text encoding               $xx
     MIME type                   <textstring> $00
     Filename                    <textstring> $00 (00)
     Content description         <textstring> $00 (00)
     Encapsulated object         <binary data>


4.17.   Play counter

   This is simply a counter of the number of times a file has been
   played. The value is increased by one every time the file begins to
   play. There may only be one "CNT" frame in each tag. When the counter
   reaches all one's, one byte is inserted in front of the counter thus
   making the counter eight bits bigger.  The counter must be at least
   32-bits long to begin with.

     Play counter   "CNT"
     Frame size     $xx xx xx
     Counter        $xx xx xx xx (xx ...)


4.18.   Popularimeter

   The purpose of this frame is to specify how good an audio file is.
   Many interesting applications could be found to this frame such as a
   playlist that features better audiofiles more often than others or it
   could be used to profile a persons taste and find other 'good' files
   by comparing people's profiles. The frame is very simple. It contains
   the email address to the user, one rating byte and a four byte play
   counter, intended to be increased with one for every time the file is
   played. The email is a terminated string. The rating is 1-255 where
   1 is worst and 255 is best. 0 is unknown. If no personal counter is
   wanted it may be omitted.  When the counter reaches all one's, one
   byte is inserted in front of the counter thus making the counter
   eight bits bigger in the same away as the play counter ("CNT").
   There may be more than one "POP" frame in each tag, but only one with
   the same email address.
   
     Popularimeter   "POP"
     Frame size      $xx xx xx
     Email to user   <textstring> $00
     Rating          $xx
     Counter         $xx xx xx xx (xx ...)


4.19.   Recommended buffer size

   Sometimes the server from which a audio file is streamed is aware of
   transmission or coding problems resulting in interruptions in the
   audio stream. In these cases, the size of the buffer can be
   recommended by the server using this frame. If the 'embedded info
   flag' is true (1) then this indicates that an ID3 tag with the
   maximum size described in 'Buffer size' may occur in the audiostream.
   In such case the tag should reside between two MPEG [MPEG] frames, if
   the audio is MPEG encoded. If the position of the next tag is known,
   'offset to next tag' may be used. The offset is calculated from the
   end of tag in which this frame resides to the first byte of the header
   in the next. This field may be omitted. Embedded tags is currently not
   recommended since this could render unpredictable behaviour from
   present software/hardware. The 'Buffer size' should be kept to a
   minimum. There may only be one "BUF" frame in each tag.

     Recommended buffer size   "BUF"
     Frame size                $xx xx xx
     Buffer size               $xx xx xx
     Embedded info flag        %0000000x
     Offset to next tag        $xx xx xx xx


4.20.   Encrypted meta frame

   This frame contains one or more encrypted frames. This enables
   protection of copyrighted information such as pictures and text, that
   people might want to pay extra for. Since standardisation of such an
   encryption scheme is beyond this document, all "CRM" frames begin with
   a terminated string with a URL [URL] containing an email address, or a
   link to a location where an email adress can be found, that belongs to
   the organisation responsible for this specific encrypted meta frame.

   Questions regarding the encrypted frame should be sent to the
   indicated email address. If a $00 is found directly after the 'Frame
   size', the whole frame should be ignored, and preferably be removed.
   The 'Owner identifier' is then followed by a short content description
   and explanation as to why it's encrypted. After the
   'content/explanation' description, the actual encrypted block follows.

   When an ID3v2 decoder encounters a "CRM" frame, it should send the
   datablock to the 'plugin' with the corresponding 'owner identifier'
   and expect to receive either a datablock with one or several ID3v2
   frames after each other or an error. There may be more than one "CRM"
   frames in a tag, but only one with the same 'owner identifier'.

     Encrypted meta frame  "CRM"
     Frame size            $xx xx xx
     Owner identifier      <textstring> $00 (00)
     Content/explanation   <textstring> $00 (00)
     Encrypted datablock   <binary data>


4.21.   Audio encryption

   This frame indicates if the actual audio stream is encrypted, and by
   whom. Since standardisation of such encrypion scheme is beyond this
   document, all "CRA" frames begin with a terminated string with a
   URL containing an email address, or a link to a location where an
   email address can be found, that belongs to the organisation
   responsible for this specific encrypted audio file. Questions
   regarding the encrypted audio should be sent to the email address
   specified. If a $00 is found directly after the 'Frame size' and the
   audiofile indeed is encrypted, the whole file may be considered
   useless.

   After the 'Owner identifier', a pointer to an unencrypted part of the
   audio can be specified. The 'Preview start' and 'Preview length' is
   described in frames. If no part is unencrypted, these fields should be
   left zeroed. After the 'preview length' field follows optionally a
   datablock required for decryption of the audio. There may be more than
   one "CRA" frames in a tag, but only one with the same 'Owner
   identifier'.

     Audio encryption   "CRA"
     Frame size         $xx xx xx
     Owner identifier   <textstring> $00 (00)
     Preview start      $xx xx
     Preview length     $xx xx
     Encryption info    <binary data>


4.22.   Linked information

   To keep space waste as low as possible this frame may be used to link
   information from another ID3v2 tag that might reside in another audio
   file or alone in a binary file. It is recommended that this method is
   only used when the files are stored on a CD-ROM or other circumstances
   when the risk of file seperation is low. The frame contains a frame
   identifier, which is the frame that should be linked into this tag, a
   URL [URL] field, where a reference to the file where the frame is
   given, and additional ID data, if needed. Data should be retrieved
   from the first tag found in the file to which this link points. There
   may be more than one "LNK" frame in a tag, but only one with the same
   contents. A linked frame is to be considered as part of the tag and
   has the same restrictions as if it was a physical part of the tag
   (i.e. only one "REV" frame allowed, whether it's linked or not).
   
     Linked information  "LNK"
     Frame size          $xx xx xx
     Frame identifier    $xx xx xx
     URL                 <textstring> $00 (00)
     Additional ID data  <textstring(s)>
   
   Frames that may be linked and need no additional data are "IPL",
   "MCI", "ETC", "LLT", "STC", "RVA", "EQU", "REV", "BUF", the text
   information frames and the URL link frames.
   
   The "TXX", "PIC", "GEO", "CRM" and "CRA" frames may be linked with the
   content descriptor as additional ID data.
   
   The "COM", "SLT" and "ULT" frames may be linked with three bytes of
   language descriptor directly followed by a content descriptor as
   additional ID data.


5.   The 'unsynchronisation scheme'

   The only purpose of the 'unsychronisation scheme' is to make the ID3v2
   tag as compatible as possible with existing software. There is no use
   in 'unsynchronising' tags if the file is only to be processed by new
   software. Unsynchronisation may only be made with MPEG 2 layer I, II
   and III and MPEG 2.5 files.

   Whenever a false synchronisation is found within the tag, one zeroed
   byte is inserted after the first false synchronisation byte. The
   format of a correct sync that should be altered by ID3 encoders is as
   follows:

         %11111111 111xxxxx

   And should be replaced with:

         %11111111 00000000 111xxxxx

   This has the side effect that all $FF 00 combinations have to be
   altered, so they won't be affected by the decoding process. Therefore
   all the $FF 00 combinations have to be replaced with the $FF 00 00
   combination during the unsynchonisation.

   To indicate usage of the unsynchronisation, the first bit in 'ID3
   flags' should be set. This bit should only be set if the tag
   contained a, now corrected, false synchronisation. The bit should
   only be clear if the tag does not contain any false synchronisations.
   
   Do bear in mind, that if a compression scheme is used by the encoder,
   the unsyncronisation scheme should be applied *afterwards*. When
   decoding a compressed, 'unsyncronised' file, the 'unsyncronisation
   scheme' should be parsed first, compression afterwards.


6.   Copyright

   Copyright (C) Martin Nilsson 1998. All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that a reference to this document is included on all
   such copies and derivative works. However, this document itself may
   not be modified in any way and reissued as the original document.

   The limited permissions granted above are perpetual and will not be
   revoked.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE AUTHORS DISCLAIMS ALL WARRANTIES, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


7.   References

   [CDDB] Compact Disc Data Base

      <url:http://www.cddb.com>

   [ISO-639-2] ISO/FDIS 639-2.
   Codes for the representation of names of languages, Part 2: Alpha-3
   code. Technical committee / subcommittee: TC 37 / SC 2

   [ISO-8859-1] ISO/IEC DIS 8859-1.
   8-bit single-byte coded graphic character sets, Part 1: Latin
   alphabet No. 1. Technical committee / subcommittee: JTC 1 / SC 2

   [ISRC] ISO 3901:1986
   International Standard Recording Code (ISRC).
   Technical committee / subcommittee: TC 46 / SC 9

   [JFIF] JPEG File Interchange Format, version 1.02

      <url:http://www.w3.org/Graphics/JPEG/jfif.txt>
      
   [MIME] Freed, N.  and N. Borenstein,  "Multipurpose Internet Mail
   Extensions (MIME) Part One: Format of Internet Message Bodies",
   RFC 2045, November 1996.
 
      <url:ftp://ftp.isi.edu/in-notes/rfc2045.txt>
      
   [MPEG] ISO/IEC 11172-3:1993.
   Coding of moving pictures and associated audio for digital storage
   media at up to about 1,5 Mbit/s, Part 3: Audio.
   Technical committee / subcommittee: JTC 1 / SC 29
   and   
   ISO/IEC 13818-3:1995
   Generic coding of moving pictures and associated audio information,
   Part 3: Audio.
   Technical committee / subcommittee: JTC 1 / SC 29
   and   
   ISO/IEC DIS 13818-3
   Generic coding of moving pictures and associated audio information,
   Part 3: Audio (Revision of ISO/IEC 13818-3:1995)


   [PNG] Portable Network Graphics, version 1.0

      <url:http://www.w3.org/TR/REC-png-multi.html>

   [UNICODE] ISO/IEC 10646-1:1993.
   Universal Multiple-Octet Coded Character Set (UCS), Part 1:
   Architecture and Basic Multilingual Plane. Technical committee
   / subcommittee: JTC 1 / SC 2

      <url:http://www.unicode.org>

   [URL] T. Berners-Lee, L. Masinter & M. McCahill, "Uniform Resource
   Locators (URL).", RFC 1738, December 1994.

      <url:ftp://ftp.isi.edu/in-notes/rfc1738.txt>


8.   Appendix


A.   Appendix A - ID3-Tag Specification V1.1

   ID3-Tag Specification V1.1 (12 dec 1997) by Michael Mutschler
   <amiga2@info2.rus.uni-stuttgart.de>, edited for space and clarity
   reasons.


A.1.   Overview


   The ID3-Tag is an information field for MPEG Layer 3 audio files.
   Since a standalone MP3 doesn't provide a method of storing other
   information than those directly needed for replay reasons, the
   ID3-tag was invented by Eric Kemp in 1996.

   A revision from ID3v1 to ID3v1.1 was made by Michael Mutschler to
   support track number information is described in A.4.


A.2.   ID3v1 Implementation

   The Information is stored in the last 128 bytes of an MP3. The Tag
   has got the following fields, and the offsets given here, are from
   0-127.

     Field      Length    Offsets
     Tag        3           0-2
     Songname   30          3-32
     Artist     30         33-62
     Album      30         63-92
     Year       4          93-96
     Comment    30         97-126
     Genre      1           127


   The string-fields contain ASCII-data, coded in ISO-Latin 1 codepage.
   Strings which are smaller than the field length are padded with zero-
   bytes.

     Tag: The tag is valid if this field contains the string "TAG". This
        has to be uppercase!

     Songname: This field contains the title of the MP3 (string as
        above).

     Artist: This field contains the artist of the MP3 (string as above).

     Album: this field contains the album where the MP3 comes from
        (string as above).

     Year: this field contains the year when this song has originally
        been released (string as above).

     Comment: this field contains a comment for the MP3 (string as
        above). Revision to this field has been made in ID3v1.1. See
        A.4.

     Genre: this byte contains the offset of a genre in a predefined
        list the byte is treated as an unsigned byte. The offset is
        starting from 0. See A.3.


A.3.   Genre List

   The following genres is defined in ID3v1 

      0.Blues
      1.Classic Rock
      2.Country
      3.Dance
      4.Disco
      5.Funk
      6.Grunge
      7.Hip-Hop
      8.Jazz
      9.Metal
     10.New Age
     11.Oldies
     12.Other
     13.Pop
     14.R&B
     15.Rap
     16.Reggae
     17.Rock
     18.Techno
     19.Industrial
     20.Alternative
     21.Ska
     22.Death Metal
     23.Pranks
     24.Soundtrack
     25.Euro-Techno
     26.Ambient
     27.Trip-Hop
     28.Vocal
     29.Jazz+Funk
     30.Fusion
     31.Trance
     32.Classical
     33.Instrumental
     34.Acid
     35.House
     36.Game
     37.Sound Clip
     38.Gospel
     39.Noise
     40.AlternRock
     41.Bass
     42.Soul
     43.Punk
     44.Space
     45.Meditative
     46.Instrumental Pop
     47.Instrumental Rock
     48.Ethnic
     49.Gothic
     50.Darkwave
     51.Techno-Industrial
     52.Electronic
     53.Pop-Folk
     54.Eurodance
     55.Dream
     56.Southern Rock
     57.Comedy
     58.Cult
     59.Gangsta
     60.Top 40
     61.Christian Rap
     62.Pop/Funk
     63.Jungle
     64.Native American
     65.Cabaret
     66.New Wave
     67.Psychadelic
     68.Rave
     69.Showtunes
     70.Trailer
     71.Lo-Fi
     72.Tribal
     73.Acid Punk
     74.Acid Jazz
     75.Polka
     76.Retro
     77.Musical
     78.Rock & Roll
     79.Hard Rock
     
   The following genres are Winamp extensions
     
     80.Folk
     81.Folk-Rock
     82.National Folk
     83.Swing
     84.Fast Fusion
     85.Bebob
     86.Latin
     87.Revival
     88.Celtic
     89.Bluegrass
     90.Avantgarde
     91.Gothic Rock
     92.Progressive Rock
     93.Psychedelic Rock
     94.Symphonic Rock
     95.Slow Rock
     96.Big Band
     97.Chorus
     98.Easy Listening
     99.Acoustic
    100.Humour
    101.Speech
    102.Chanson
    103.Opera
    104.Chamber Music
    105.Sonata
    106.Symphony
    107.Booty Bass
    108.Primus
    109.Porn Groove
    110.Satire
    111.Slow Jam
    112.Club
    113.Tango
    114.Samba
    115.Folklore
    116.Ballad
    117.Power Ballad
    118.Rhythmic Soul
    119.Freestyle
    120.Duet
    121.Punk Rock
    122.Drum Solo
    123.A capella
    124.Euro-House
    125.Dance Hall


A.4.   Track addition - ID3v1.1

   In ID3v1.1, Michael Mutschler revised the specification of the
   comment field in order to implement the track number. The new format
   of the comment field is a 28 character string followed by a mandatory
   null ($00) character and the original album tracknumber stored as an
   unsigned byte-size integer. In such cases where the 29th byte is not
   the null character or when the 30th is a null character, the
   tracknumber is to be considered undefined.


9.   Author's Address

   Martin Nilsson
   Rydsv�gen 246 C. 30
   S-584 34 Link�ping
   Sweden

   Email: nilsson at id3.org

   Co-authors:

   Johan Sundstr�m   Email: johan at id3.org
