Album/Movie/Show Title

The 'Album/Movie/Show title' frame is intended for the title of the recording (or source of sound) from which the audio in the file is taken.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Attached Picture

This frame contains a picture directly related to the audio file however, This frame is defined differently in different versions.

In ID3v2.2, Image format is preferably "PNG" or "JPG". 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 instead of picture data. The use of linked files should however be used restrictively since there is the risk of separation of files.

The format for this frame is as follows:

Encoding = $xx
Image Format = $xx xx xx
Picture type = $xx
Description = [n bytes of encoded data] $00 (00)
Picture data = [n bytes of binary data]

In ID3v2.3 and ID3v2.4, Image format is the MIME type and subtype for the image. In the event that the MIME media type name is omitted, "image/" will be implied. The "image/png" (PNG) or "image/jpeg" (JFIF) picture format should be used when interoperability is wanted. Description is a short description of the picture, represented as a terminated text string. There may be several pictures attached to one file, in their individual "APIC" 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 the possibility to put only a link to the image file by using the 'MIME type' "-->" and having a complete URL [URL] instead of picture data. The use of linked files should however be used sparingly since there is the risk of separation of files.

The format for this frame is as follows:

Encoding = $xx
MIME Type = [ISO-8859-1 encoded string] $00
Picture type = $xx
Description = [n bytes of encoded data] $00 (00)
Picture data = [n bytes of binary data]

Defined Picture types:

$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. label 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

See below for an example of what this frame could look like:

Audio Encryption

This frame indicates if the actual audio stream is encrypted, and by whom. Since standardisation of such encryption scheme is beyond this document, all audio encryption 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 audio file indeed is encrypted, the whole file may be considered useless.

After the 'Owner identifier', a two byte integer represented as seconds 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 data block required for decryption of the audio. There may be more than one audio encryption frames in a tag, but only one with the same 'Owner identifier'.

The format for this frame is as follows:

Owner identifier = [ISO-8859-1 encoded string] $00
Priview start = $xx xx
Priview length = $xx xx
Encryption info = [n bytes of binary data]

See below for an example of what this frame could look like:

BPM (Beats Per Minute)

The 'BPM' frame contains the number of beats per minute in the main part of the audio. The BPM is an integer and represented as a numerical string.

The frames format is as follows:

Encoding = $xx
Information = Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Band/Orchestra/Accompaniment

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

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Comments

This frame is intended for any kind of full text information that does not fit in any other frame. It consists of a frame header followed by encoding, ISO-639-2 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 description.

The frames format is as follows:

Encoding = $xx
Language = [ISO-639-2 language code]
Short content description = [n bytes of encoded data] $00 (00)
The actual text = [n bytes of encoded data]

See below for an example of what this frame could look like:

Commercial Frame

This frame enables several competing offers in the same tag by bundling all needed information. That makes this frame rather complex but it's an easier solution than if one tries to achieve the same result with several frames. The frame begins, after the frame ID, size and encoding fields, with a price string field. A price is constructed by one three character currency code, encoded according to ISO-4217 alphabetic currency code, followed by a numerical value where "." is used as decimal separator. In the price string several prices may be concatenated, separated by a "/" character, but there may only be one currency of each type.

The price string is followed by an 8 character date string in the format YYYYMMDD, describing for how long the price is valid. After that is a contact URL, with which the user can contact the seller, followed by a one byte 'received as' field. It describes how the audio is delivered when bought according to the following list:

$00 = Other
$01 = Standard CD album with other songs
$02 = Compressed audio on CD
$03 = File over the Internet
$04 = Stream over the Internet
$05 = As note sheets
$06 = As note sheets in a book with other sheets
$07 = Music on other media
$08 = Non-musical merchandise

Next follows a terminated string with the name of the seller followed by a terminated string with a short description of the product. The last thing is the ability to include a company logotype. The first of them is the 'Picture MIME type' field containing information about which picture format is used. In the event that the MIME media type name is omitted, "image/" will be implied. Currently only "image/png" and "image/jpeg" are allowed. This format string is followed by the binary picture data. This two last fields may be omitted if no picture is attached. There may be more than one 'commercial frame' in a tag, but no two may be identical.

The frames format is as follows:

Encoding = $xx
Price string = [ISO-8859-1 encoded string] $00
Valid until = [ISO-8859-1 encoded string]
Contact URL = [ISO-8859-1 encoded string] $00
Received as = $xx
Name of seller = [n bytes of encoded data] $00 (00)
Description = [n bytes of encoded data] $00 (00)
Picture MIME type = [ISO-8859-1 encoded string] $00
Seller logo = [n bytes of binary data]

See below for an example of what this frame could look like:

Commercial Information

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 "WCOM" frame in a tag, but not with the same content.

The frames format is as follows:

URL = [ISO-8859-1 encoded string]

See below for an example of what this frame could look like:

Composer

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

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Conductor/Performer Refinement

The 'Conductor' frame is used for the name of the conductor.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Content Group Description

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").

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Content Type

The content type frame is a tricky one as it's practical use is different when compared to the standard, both ID3v2.2 and ID3v2.3 define this frame as follows. previously (in ID3v1.1, see genres) 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 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)". However, the more practical use of this frame and what can be found in real world files is found in ID3v2.4's definition. This definition is as follows the 'Content type', which ID3v1 was stored as a one byte numeric value only, is now a string. You may use one or several of the ID3v1 types as numerical strings, or, since the category list would be impossible to maintain with accurate and up to date categories, define your own. Example: "21" $00 "Eurodisco" $00.

You may also use any of the following keywords:

Remix = "RX"
Cover = "CR"

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Copyright Message

The 'Copyright message' frame, in which the string 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 audio is public domain. Every time this field is displayed the field must be preceded with the copyright symbol "©".

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Copyright/Legal Information

The 'Copyright/Legal information' frame is a URL pointing at a webpage where the terms of use and ownership of the file is described.

The frames format is as follows:

URL = [ISO-8859-1 encoded string]

See below for an example of what this frame could look like:

Date

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

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Encoded By

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.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Encoding Time

The 'Encoding time' frame contains a timestamp describing when the audio was encoded. Timestamp format is defined as yyyy-MM-ddTHH:mm:ss (year, "-", month, "-", day, "T", hour (out of 24), ":", minutes, ":", seconds) or a subset.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

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 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 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'.

The frames format is as follows:

Owner Identifier = [ISO-8859-1 encoded string] $00
Content/Explanation = [ISO-8859-1 encoded string] $00
Encrypted Datablock = [n bytes of binary data]

See below for an example of what this frame could look like:

Encryption Method Registration

To identify with which method a frame has been encrypted the encryption method must be registered in the tag with this frame. The 'Owner identifier' is a null-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 encryption method. Questions regarding the encryption method should be sent to the indicated email address. The 'Method symbol' contains a value that is associated with this method throughout the whole tag, in the range $80-F0. All other values are reserved. The 'Method symbol' may optionally be followed by encryption specific data. There may be several "ENCR" frames in a tag but only one containing the same symbol and only one containing the same owner identifier. The method must be used somewhere in the tag. See the description of the frame encryption flag in the ID3v2 Frame structure section for more information.

The frames format is as follows:

Owner Identifier = [ISO-8859-1 encoded string] $00
Method Symbol = $xx
Encrypted Data = [n bytes of binary data]

See below for an example of what this frame could look like:

Equalization

The equalization frame is defined differently depending on the ID3v2 version and gradually supports more and more freatures. Below each format is defined in ascending order by verson number. It is worth noting that each equalization frame is a subjective, alignment frame no matter the version. However, the main purpose of this frame is to allows users to predefine an equalisation curve within the audio file.

In ID3v2.2 and ID3v2.3, 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, III, 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.

The frames format is as follows:

Adjustment bits = $xx

Increment/decrement = %x (MSB of the Frequency)
Frequency = (lower 15 bits)
Adjustment = $xx (xx ...)
* one to many adjustments may be present

In ID3v2.4, The 'interpolation method' describes which method is preferred when an interpolation between the adjustment point that follows. The following methods are currently defined:

$00 = Band

No interpolation is made. A jump from one adjustment level to another occurs in the middle between two adjustment points.

$01 = Linear

Interpolation between adjustment points is linear.

The 'identification' string is used to identify the situation and/or device where this adjustment should apply. The following is then repeated for every adjustment point:

Frequency = $xx xx
Volume adjustment = $xx xx

The frequency is stored in units of 1/2 Hz, giving it a range from 0 to 32767 Hz. The volume adjustment is encoded as a fixed point decibel value, 16 bit signed integer representing (adjustment*512), giving +/- 64 dB with a precision of 0.001953125 dB. E.g. +2 dB is stored as $04 00 and -2 dB is $FC 00. Adjustment points should be ordered by frequency and one frequency should only be described once in the frame.

The frames format is as follows:

Interpolation method = $xx
Identification = [ISO-8859-1 encoded string] $00

Frequency = $xx xx
Volume adjustment = $xx xx
* one to many adjustments may be present

See below for an example of what this frame could look like:

Event Timing Codes

This frame allows synchronisation with key events in the audio. The header is:

Time stamp format = $xx

Where time stamp format is:

$01 = Absolute time, 32 bit sized, using MPEG frames as unit
$02 = Absolute time, 32 bit sized, using milliseconds as unit

Absolute 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 xx xx

The 'Time stamp' is set to zero if directly at the beginning of the sound or after the previous event. All events must 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 = main part start
$04 = outro start
$05 = outro end
$06 = verse start
$07 = refrain start
$08 = interlude start
$09 = theme start
$0A = variation start
$0B = key change
$0C = time change
$0D = momentary unwanted noise (Snap, Crackle & Pop)
$0E = sustained noise
$0F = sustained noise end
$10 = intro end
$11 = main part end
$12 = verse end
$13 = refrain end
$14 = theme end
$15 = profanity
$16 = profanity end
$17-$DF = reserved for future use
$E0-$EF = not predefined synch 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)

Terminating the start events such as "intro start" is optional. The 'Not predefined synch's ($E0-EF) are for user events. You might want to synchronise your music to something, like setting off an explosion on-stage, activating a screensaver etc. There may only be one event timing codes frame in each tag.

The frames format is as follows:

Time stamp format = $xx

Type of event = $xx
Time stamp = $xx xx xx xx
* one to many events may be present

See below for an example of what this frame could look like:

File Type

The 'File type' frame indicates which type of audio this tag defines. The following type and refinements are defined:

MIME = MIME type follows
MPG = MPEG Audio

/1 = MPEG 1/2 layer I
/2 = MPEG 1/2 layer II
/3 = MPEG 1/2 layer III
/2.5 = MPEG 2.5
/AAC = Advanced Audio Compression

VQF = Transform-domain Weighted Interleave Vector Quantisation
PCM = Pulse Code Modulated Audio

but other types may be used, but not for these types though. This is used in a similar way to the predefined types in the media type frame, but without parentheses. If this frame is not present audio type is assumed to be "MPG".

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

File Owner/Licensee

The 'File owner/licensee' frame contains the name of the owner or licensee of the file and it's contents.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

General Encapsulated Object

In this frame any type of file can be encapsulated. After the header, 'Frame size' and 'Encoding' follows 'MIME type' represented as as a terminated string encoded with ISO-8859-1. The filename is case sensitive and is encoded as 'Encoding'. 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 general encapsulated object frame in each tag, but only one with the same content descriptor.

The frames format is as follows:

Encoding = $xx
MIME type = [ISO-8859-1 encoded string] $00
Filename = [n bytes of encoded data] $00 (00)
Content description = [n bytes of encoded data] $00 (00)
Encapsulated object = [n bytes of binary data]

See below for an example of what this frame could look like:

Group Identification Registration

This frame enables grouping of otherwise unrelated frames. This can be used when some frames are to be signed. To identify which frames belongs to a set of frames a group identifier must be registered in the tag with this frame. The 'Owner identifier' is a null-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 grouping. Questions regarding the grouping should be sent to the indicated email address. The 'Group symbol' contains a value that associates the frame with this group throughout the whole tag, in the range $80-F0. All other values are reserved. The 'Group symbol' may optionally be followed by some group specific data, e.g. a digital signature. There may be several "GRID" frames in a tag but only one containing the same symbol and only one containing the same owner identifier. The group symbol must be used somewhere in the tag. See the description of the frame grouping flag in the ID3v2 frame structure for more information.

The frames format is as follows:

Owner identifier = [ISO-8859-1 encoded string] $00
Group symbol = $xx
Group dependent data = [n bytes of binary data]

See below for an example of what this frame could look like:

ISRC

The 'ISRC' frame should contain the 12 character International Standard Recording Code. Information about how this code is structured can be be found on the International Federation of the Phonographic Industries domain.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Initial Key

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", e.g. "Dbm" $00. Off key is represented with an "o" only.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Internet Radio Station Name

The 'Internet radio station name' frame contains the name of the internet radio station from which the audio is streamed.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Internet Radio Station Owner

The 'Internet radio station owner' frame contains the name of the owner of the internet radio station from which the audio is streamed.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Interpreted, Remixed, or Modified By

The 'Interpreted, remixed, or modified by' frame contains more information about the people behind a remix and similar interpretations of another existing piece.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Involved People List

This frame features the same functionality in both ID3v2.2 and ID3v2.3 however, is defined differently in ID3v2.4. In ID3v2.4 this frame is merged into the text frame family and allows the container writer to

In ID3v2.2 and ID3v2.3 this frame is defined as, there is usually 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 involved persons list frame in each tag.

The frames format is as follows:

Encoding = $xx

Role = [n bytes of encoded data] $00 (00)
Involvee = [n bytes of encoded data] ($00 (00))
* one to many roles and involved people may be present

However, in ID3v2.4 this structure is dropped to allow the container writer to define how to separate role and involvee.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Language(s)

The 'Language' frame should contain the languages of the text or lyrics spoken or sung in the audio. 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 the amount of their usage.

The frames format is as follows:

Encoding = $xx

Code = [n bytes of encoded data] ($00 (00))
* one to many code(s) may be present

See below for an example of what this frame could look like:

Lead Performer(s)/Soloist(s)

The 'Lead artist/Lead performer/Soloist/Performing group' is used for the main artist.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Length

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

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Linked Information

To keep information duplication 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 separation 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 linked information 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 "RVRB" frame allowed, whether it's linked or not).

The frames format is as follows:

URL = [ISO-8859-1 encoded string] $00
ID and additional data = [ISO-8859-1 encoded string]

Frames that may be linked and need no additional data are Seek Point Index, Event Timing Codes, Equalization, Music CD Identifier, MPEG Location Lookup Table, Ownership Frame, Relative Volume Adjustment, Reverb, Synchronised Tempo Codes, Recommended Buffer Size, text information frames, and URL link frames.

The Audio Encryption, Attached Picture, Encrypted Meta Frame, General Encapsulated Object, and User Defined Text Information Frame frames may be linked with the content descriptor as additional ID data.

The Terms of Use Frame may be linked with the language field as additional ID data.

The Private Frame may be linked with the owner identifier as additional ID data.

The Comments, Synchronised Lyric/Text, and Unsynchronised Lyric/Text Transcription frames may be linked with three bytes of language descriptor directly followed by a content descriptor as additional ID data.

See below for an example of what this frame could look like:

Lyricist/Text Writer

The 'Lyricist/Text writer' frame is intended for the writer of the text or lyrics in the recording.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

MPEG Location Lookup Table

To increase performance and accuracy of jumps within a MPEG audio file, frames with time codes in different locations in the file might be useful. This ID3v2 frame includes references that the software can use to calculate positions in the file. After the frame header follows a descriptor of how much the "frame counter" should be increased 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 MPEG location lookup table frame in each tag.

The frames format is as follows:

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

Deviation in bytes = %xxx...
Deviation in milliseconds = %xxx...
* one to many deviations may be present

See below for an example of what this frame could look like:

Musician Credits List

The 'Musician credits list' is intended as a mapping between instruments and the musician that played it. Every odd field is an instrument and every even is an artist or a comma delimited list of artists. For the sake of consistency, each pairing will be separated by "/" so that it is easy to identify each tuple.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Media Type

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 Content Type frame. Predefined refinements is appended after the media type, e.g. "(CD/S)" or "(VID/PAL/VHS)".

The following type and refinements are defined:

DIG = Other digital media

/A = Analogue transfer from media

ANA = Other analogue media

/WAC = Wax cylinder
/8CA = 8-track tape cassette

CD = Compact disc

/A = Analogue transfer from media
/DD = DDD
/AD = ADD
/AA = AAD

LD = Laserdisc

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 = Analogue transfer from media

DAT = DAT

/A = Analogue 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, non-linear, 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 = Analogue transfer from media

DVD = DVD

/A = Analogue 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)

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Mood

The 'Mood' frame is intended to reflect the mood of the audio with a few keywords, e.g. "Romantic" or "Sad".

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

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. The frame consists of a binary dump of the Table Of Contents from the CD, which is a header of 4 bytes and then 8 bytes/track on the CD plus 8 bytes for the 'lead out', making a maximum of 804 bytes. The offset to the beginning of every track on the CD should be described with a four bytes absolute CD-frame address per track, and not with absolute time. When this frame is used the presence of a valid Track Number/Position in Set frame is required, even if the CD's only has one track. It is recommended that this frame is always added to tags originating from CDs. There may only be one Music CD Identifier frame in each tag.

The frames format is as follows:

Table of contents = [n bytes of binary data]

See below for an example of what this frame could look like:

Official Internet Radio Station Homepage

The 'Official Internet radio station homepage' contains a URL pointing at the homepage of the internet radio station. The frames format is as follows:

URL = [ISO-8859-1 encoded string]

See below for an example of what this frame could look like:

Official Artist/Performer Webpage

The 'Official artist/performer webpage' frame is a URL pointing at the artists official webpage. There may be more than one of this frame type in a tag if the audio contains more than one performer, but not with the same content.

The frames format is as follows:

URL = [ISO-8859-1 encoded string]

See below for an example of what this frame could look like:

Official Audio File Webpage

The 'Official audio file webpage' frame is a URL pointing at a file specific webpage.

The frames format is as follows:

URL = [ISO-8859-1 encoded string]

See below for an example of what this frame could look like:

Official Audio Source Webpage

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.

The frames format is as follows:

URL = [ISO-8859-1 encoded string]

See below for an example of what this frame could look like:

Original Album/Movie/Show Title

The 'Original album/movie/show title' frame is intended for the title of the original recording (or source of sound), if for example the music in the file should be a cover of a previously released song.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Original artist(s)/performer(s)

The 'Original artist/performer' frame is intended for the performer of the original recording, if for example the music in the file should be a cover of a previously released song.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Original Filename

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.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Original Lyricist(s)/Text Writer(s)

The 'Original lyricist/text writer' frame is intended for the text writer of the original recording, if for example the music in the file should be a cover of a previously released song.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Original Release Time

The 'Original release time' frame contains a timestamp describing when the original recording of the audio was released. Timestamp format is defined as follows yyyy-MM-ddTHH:mm:ss or a subset of the format.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Original Release Year

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 Year frame.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Ownership

The ownership frame might be used as a reminder of a made transaction or, if signed, as proof. Note that the Terms of Use frame and File Owner/Licensee frame frames are good to use in conjunction with this one. The frame begins, after the frame ID, size and encoding fields, with a 'price paid' field. The first three characters of this field contains the currency used for the transaction, encoded according to ISO-4217 alphabetic currency code. Concatenated to this is the actual price paid, as a numerical string using "." as the decimal separator. Next is an 8 character date string (YYYYMMDD) followed by a string with the name of the seller as the last field in the frame. There may only be one ownership frame in a tag. 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 Year frame.

The frames format is as follows:

Encoding = $xx
Price payed = [ISO-8859-1 encoded string] $00
Date of purch. = [ISO-8859-1 encoded string]
Seller = [n bytes of encoded data]

See below for an example of what this frame could look like:

Part of a Set

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 Album/Movie/Show Title 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".

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Payment

The 'Payment' frame is a URL pointing at a webpage that will handle the process of paying for this file.

The frames format is as follows:

URL = [ISO-8859-1 encoded string]

See below for an example of what this frame could look like:

Performer Sort Order

The 'Performer sort order' frame defines a string which should be used instead of the performer (TPE2) for sorting purposes.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

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 Play Counter 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. For example, if the counter section is 32-bits and 10 of them are set to 1, the file has been played 10 times.

This frame is formated as:

Counter = [n bytes of binary data]

See below for an example of what this frame could look like:

Playlist Delay

The 'Playlist delay' defines the numbers of milliseconds of silence that should be inserted before this audio. The value zero indicates that this is a part of a multifile audio track that should be played continuously.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

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 audio files more often than others or it could be used to profile a person's taste and find other 'good' files by comparing people's profiles. The frame 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 frame. There may be more than one Popularimeter frame in each tag, but only one with the same email address.

This frame is formated as:

User email = [ISO-8859-1 encoded string] $00
Rating = $xx
Counter = [n bytes of binary data]

See below for an example of what this frame could look like:

Position Synchronisation

This frame delivers information to the listener of how far into the audio stream he picked up; in effect, it states the time offset from the first frame in the stream.

The frames format is as follows:

Time stamp format = $xx
Position = $xx

Where time stamp format is:

$01 = Absolute time, 32 bit sized, using MPEG frames as unit
$02 = Absolute time, 32 bit sized, using milliseconds as unit

and position is where in the audio the listener starts to receive, i.e. the beginning of the next frame. If this frame is used in the beginning of a file the value is always 0. There may only be one Position Synchronisation frame in each tag.

See below for an example of what this frame could look like:

Private Frame

This frame is used to contain information from a software producer that its program uses and does not fit into the other frames. The frame consists of an 'Owner identifier' string and the binary data. The 'Owner identifier' is a null-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 the frame. Questions regarding the frame should be sent to the indicated email address. The tag may contain more than one Private frame but only with different contents.

The frames format is as follows:

Owner identifier = [ISO-8859-1 encoded string] $00
Private data = [n bytes of binary data]

See below for an example of what this frame could look like:

Produced Notice

The 'Produced notice' frame, in which the string must begin with a year and a space character (making five characters), is intended for the production copyright holder of the original sound, not the audio file itself. The absence of this frame means only that the production copyright information is unavailable or has been removed, and must not be interpreted to mean that the audio is public domain. Every time this field is displayed the field must be preceded with "Produced " ⓟ " ". Note, ⓟ is not available in ISO-8859-1 (encoding $00) thus, different encodings must be used.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Publisher

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

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Publishers Official Webpage

The 'Publishers official webpage' frame is a URL pointing at the official webpage for the publisher. The frames format is as follows:

The frames format is as follows:

URL = [ISO-8859-1 encoded string]

See below for an example of what this frame could look like:

Recommended Buffer Size

Sometimes the server from which an 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 set then this indicates that an ID3 tag with the maximum size described in 'Buffer size' may occur in the audio stream. In such case the tag should reside between two 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 are generally not recommended since this could render unpredictable behaviour from present software/hardware.

For applications like streaming audio it might be an idea to embed tags into the audio stream though. If the clients connects to individual connections like HTTP and there is a possibility to begin every transmission with a tag, then this tag should include a 'recommended buffer size' frame. If the client is connected to a arbitrary point in the stream, such as radio or multicast, then the 'recommended buffer size' frame should be included in every tag.

This frame is formated as:

Buffer size = $xx xx xx
Embedded info flag = %0000000x
Offset to next tag = $xx xx xx xx

See below for an example of what this frame could look like:

Recording Dates

The 'Recording dates' frame is a intended to be used as complement to the Year, Date and Time frames. E.g. "4th-7th June, 12th June" in combination with the Year frame.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Recording Time

The 'Recording time' frame contains a timestamp describing when the audio was recorded. Timestamp format is described in as yyyy-MM-ddTHH:mm:ss or a subset of the stated format.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Relative Volume Adjustment

The purpose of this frame is to allow the tagger to define a set volume level for the sake of the end user. However, this frame has a different definition depending on the desired standard. formats for this frame will be listed in ascending order from ID3v2.2 to ID3v2.4.

ID3v2.2 and ID3v2.3 have a similar definition for the 'Relative volume adjustment' frame with the only difference being that ID3v2.3 offers more options. It allows the user to say how much he or she 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 or 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, if no other data follows, be completely omitted. There may only be one 'Relative volume adjustment' frame in each tag. This version of the frame is formated as:

Increment/decrement = %00yyyyxx *
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 ...)
*options labeled as 'y' are only available in ID3v2.3 and will be ignored by an ID3v2.2 decoder

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. These bits are labeled as 'x' in the frames format above. The 'Bits used for volume descr.' field is normally $10 (16 bits) for MPEG 2 layer I, II, III, 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 descr.' is not a multiple of eight.

As stated prior ID3v2.3 has more options when compared to ID3v2.2 and can be accessed by setting the bits marked with 'y' in the Increment/decrement section, These are defined below.

The datablock is then optionally followed by a volume definition for the left and right back channels. If this information is appended to the frame the first two channels will be treated as front channels. In the 'Increment/decrement' field bit 2 is used to indicate the right back channel and bit 3 for the left back channel.

Relative volume change, right back = $xx xx (xx ...)
Relative volume change, left back = $xx xx (xx ...)
Peak volume right = $xx xx (xx ...)
Peak volume left = $xx xx (xx ...)

If the center channel adjustment is present the following is appended to the existing frame, after the left and right back channels. The center channel is represented by bit 4 in the 'Increase/decrement' field.

Relative volume change, center = $xx xx (xx ...)
Peak volume center = $xx xx (xx ...)

If the bass channel adjustment is present the following is appended to the existing frame, after the center channel. The bass channel is represented by bit 5 in the 'Increase/decrement' field.

Relative volume change, bass = $xx xx (xx ...)
Peak volume bass = $xx xx (xx ...)

In ID3v2.4 all of the above information is discarded in favour of a redefinition of the 'Relative volume adjustment' frame. It's goal is the exact same except, The volume adjustment is encoded as a fixed point decibel value, 16 bit signed integer representing (adjustment*512), giving +/- 64 dB with a precision of 0.001953125 dB. E.g. +2 dB is stored as $04 00 and -2 dB is $FC 00. There may be more than one 'Relative volume adjustment' frame in each tag, but only one with the same identification string. The 'identification' string is used to identify the situation and/or device where this adjustment should apply. 'Bits representing peak' can be any number between 0 and 255. 0 means that there is no 'Peak volume' field. The peak volume field is always padded to whole bytes, setting the most significant bits to zero. This version of the frame is formated as:

Identification = [ISO-8859-1 encoded string] $00

Type of channel = $xx
Volume adjustment = $xx xx
Bits representing peak = $xx
Peak volume = $xx xx (xx ...)
* one to many adjustments may be present

They type of adjustment field is defined below:

$00 = Other
$01 = Master volume
$02 = Front right
$03 = Front left
$04 = Back right
$05 = Back left
$06 = Front centre
$07 = Back centre
$08 = Subwoofer

See below for an example of what this frame could look like:

Release Time

The 'Release time' frame contains a timestamp describing when the audio was first released. Timestamp format is defined as yyyy-MM-ddTHH:mm:ss or a subset.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Reverb

Yet another subjective frame, with which you can 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, 50% of that 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 "RVRB" frame in each tag.

This frame is formated as:

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

See below for an example of what this frame could look like:

Seek Frame

This frame indicates where other tags in a file/stream can be found. The 'minimum offset to next tag' is calculated from the end of this tag to the beginning of the next. There may only be one 'seek frame' in a tag.

The frames format is as follows:

Minimum offset to next tag = $xx xx xx xx

See below for an example of what this frame could look like:

Seek Point Index

Audio files with variable bit rates are intrinsically difficult to deal with in the case of seeking within the file. The 'audio seek point index' frame makes seeking easier by providing a list of seek points within the audio file. The seek points are a fractional offset within the audio data, providing a starting point from which to find an appropriate point to start decoding. The presence of an 'audio seek point index' frame requires the existence of a Length frame, indicating the duration of the file in milliseconds. There may only be one 'audio seek point index' frame in a tag.

The frames format is as follows:

Indexed data start (S) = $xx xx xx xx
Indexed data length (L) = $xx xx xx xx
Number of index points (N) = $xx xx
Bits per index point (b) = $xx

Fraction at index (Fi) = $xx (xx)
* there may be one to many Fractions

'Indexed data start' is a byte offset from the beginning of the file. 'Indexed data length' is the byte length of the audio data being indexed. 'Number of index points' is the number of index points, as the name implies. The recommended number is 100. 'Bits per index point' is 8 or 16, depending on the chosen precision. 8 bits works well for short files (less than 5 minutes of audio), while 16 bits is advantageous for long files. 'Fraction at index' is the numerator of the fraction representing a relative position in the data. The denominator is 2 to the power of b.

Here are the algorithms to be used in the calculation. The known data must be the offset of the start of the indexed data (S), the offset of the end of the indexed data (E), the number of index points (N), the offset at index i (Oi). We calculate the fraction at index i (Fi).

Oi is the offset of the frame whose start is soonest after the point for which the time offset is (i/N * duration).

The frame data should be calculated as follows:

Fi = Oi/L * 2^b (rounded down to the nearest integer)

Offset calculation should be calculated as follows from data in the frame:

Oi = (Fi/2^b)*L (rounded up to the nearest integer)

See below for an example of what this frame could look like:

Set Subtitle

The 'Set subtitle' frame is intended for the subtitle of the part of a set this track belongs to.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Signature Frame

This frame enables a group of frames, grouped with the Group identification registration, to be signed. Although signatures can reside inside the registration frame, it might be desired to store the signature elsewhere, e.g. in watermarks. There may be more than one 'signature frame' in a tag, but no two may be identical.

This frame is formated as:

Group symbol = $xx
Signature = [n bytes of binary data]

See below for an example of what this frame could look like:

Size

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

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Software/Hardware And Settings Used For Encoding

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.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Subtitle/Description Refinement

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

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Synchronised Lyric/Text

This is a 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 text string. If no descriptor is entered, 'Content descriptor' is $00 (00) only.

The frames format is as follows:

Encoding = $xx
Language = $xx xx xx
Time stamp format = $xx
Content type = $xx
Content descriptor = [n bytes of encoded data] $00 (00)

Time stamp format is defined as:

$01 = Absolute time, 32 bit sized, using MPEG frames as unit
$02 = Absolute time, 32 bit sized, using milliseconds as unit

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

Content type is defined as:

$00 = other
$01 = lyrics
$02 = text transcription
$03 = movement/part name (e.g. "Adagio")
$04 = events (e.g. "Don Quijote enters the stage")
$05 = chord (e.g. "Bb F Fsus")
$06 = trivia/'pop up' information
$07 = URLs to webpages
$08 = URLs to images

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) = [n bytes of encoded data]
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 this frame and must be used after every entry (name, event etc.) when content type $03 - $04 is used.

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).

There may be more than one 'Synchronised Lyric/Text' frame in each tag, but only one with the same language and content descriptor.

See below for an example of what this frame could look like:

Synchronised 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 MUST 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 "SYTC" frame in each tag.

The frames format is as follows:

Time stamp format = $xx

Tempo = [n bytes of encoded data]
Time stamp = $xx xx xx xx
* there may be one to many tempo codes

Where time stamp format is:

$01 = Absolute time, 32 bit sized, using MPEG frames as unit
$02 = Absolute time, 32 bit sized, using milliseconds as unit

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

See below for an example of what this frame could look like:

Tagging Time

The 'Tagging time' frame contains a timestamp describing then the audio was tagged. Timestamp format is defined as yyyy-MM-ddTHH:mm:ss or a subset.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Terms of Use

This frame contains a brief description of the terms of use and ownership of the file. More detailed information concerning the legal terms might be available through the Copyright/Legal Information frame. Newlines are allowed in the text. There may be more than one 'Terms of use' frame in a tag, but only one with the same 'Language'

The frames format is as follows:

Encoding = $xx
Language = $xx xx xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Time

The 'Time' frame is a numeric string in the HHMM format containing the time for the recording. This field is always four characters long.

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Title Sort Order

The 'Title sort order' frame defines a string which should be used instead of the title (Title/Song Name/Content Description) for sorting purposes.

This frame is formated as:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Title/Song Name/Content Description

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

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Track Number/Position In Set

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 number of tracks/elements on the original recording. E.g. "4/9".

The frames format is as follows:

Encoding = $xx
Information = [n bytes of encoded data]

See below for an example of what this frame could look like:

Unique File Identifier

This frame's purpose is to be able to identify the audio file in a database, that may provide more information relevant to the content. Since standardisation of such a database is beyond this document, all UFID frames begin with an 'owner identifier' field. It is a null- 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 database implementation. Questions regarding the database should be sent to the indicated email address. The 'Owner identifier' must be non-empty (more than just a termination). The 'Owner identifier' is then followed by the actual identifier, which may be up to 64 bytes. There may be more than one of this frame type in a tag, but only one with the same 'Owner identifier'.

The frames format is as follows:

Owner identifier = [ISO-8859-1 encoded string] $00
Identifier = [up to 64 bytes of encoded data]

See below for an example of what this frame could look like:

Unsynchronised Lyric/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. There may be more than one 'Unsynchronised lyrics/text transcription' frame in each tag, but only one with the same language and content descriptor.

The frames format is as follows:

Encoding = $xx
Language = $xx xx xx
Content descriptor = [n bytes of encoded data] $00 (00)
Lyrics/Text = [n bytes of encoded data]

See below for an example of what this frame could look like: