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Format

MPEG Audio Stream Layer II

Download XML

Summary

Name
MPEG Audio Stream Layer II
Identifiers
  • MIME: audio/mpeg
  • Library of Congress Format Description Identifier: fdd000338
  • PUID: fmt/198
Format type
Audio
Description
MPEG Audio Stream Layer II is a lossy audio compression format defined by ISO/IEC 11172-3 standard. The format was initiated by the Digital Audio Broadcast (DAB) project financed by the European Union as a part of the EUREKA research program in the late 1980s. The format first appeared in early 1990s, with its encoding derived from the MUSICAM (Masking pattern adapted Universal Subband Integrated Coding And Multiplexing) audio codec, chosen for its simplicity and error resistance. It is a predecessor to MPEG 1/2 Audio Layer III and often referred to as MP2.
Note
https://www.loc.gov/preservation/digital/formats/fdd/fdd000338.shtml https://en.wikipedia.org/wiki/MPEG-1_Audio_Layer_II https://www.w3.org/TR/mse-byte-stream-format-mpeg-audio/ http://www.library.snls.org.sz/archive/doc/wikipedia/wikipedia-terodump-0.1/tero-dump/wikipedia/mp/MP3.html
File extensions
mp2, mpw, mpa
Source
Digital Preservation Department / The National Archives

Relationships

Is previous version of
Is supertype of

Internal signatures

MPEG-1 Audio Layer II (protected)

Note
You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-1, layer II, protected (FFFCh); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value Ebh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFFCh) repeat

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
None
Byte Sequence
FFFC[10:EB]{45-1726}FFFC[10:EB]{45-1726}FFFC[10:EB]{45-1726}FFFC[10:EB]{45-1726}
Endianness
None

MPEG-1 Audio Layer II (unprotected)

Note
You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-1, layer II, unprotected (FFFDh); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value EBh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFFDh) repeat

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
None
Byte Sequence
FFFD[10:EB]{45-1726}FFFD[10:EB]{45-1726}FFFD[10:EB]{45-1726}FFFD[10:EB]{45-1726}
Endianness
None

MPEG-2 Audio Layer II (protected)

Note
You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-2, layer II, protected (FFF4h); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value Ebh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFF4h) repeat

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
None
Byte Sequence
FFF4[10:EB]{45-1726}FFF4[10:EB]{45-1726}FFF4[10:EB]{45-1726}FFF4[10:EB]{45-1726}
Endianness
None

MPEG-2 Audio Layer II (unprotected)

Note
You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-2, layer II, unprotected (FFF5h); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value EBh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFF5h); repeat

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
None
Byte Sequence
FFF5[10:EB]{45-1726}FFF5[10:EB]{45-1726}FFF5[10:EB]{45-1726}FFF5[10:EB]{45-1726}
Endianness
None

MPEG-1 Audio Layer II with ID3v2 Metadata Tag (protected)

Note
You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-1, layer II, protected (FFFCh); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value EBh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFFCh) Regularly-spaced frame headers should always be discoverable near EOF. An ID3v1 tag of up to 355 bytes may be present at EOF. The BOF byte sequence represents the MP3 ID3 tag.

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
None
Byte Sequence
494433
Endianness
None
Min Frag Length
Absolute from EOF
Offset
0
Max offset
None
Byte Sequence
FFFC[10:EB]{45-1726}FFFC[10:EB]{45-1726}FFFC[10:EB]{45-1726}FFFC[10:EB]{45-1726}FFFC[10:EB]{7-500}000000{36-1426}
Endianness
None

MPEG-1 Audio Layer II with ID3v2 Metadata Tag (unprotected)

Note
You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-1, layer II, unprotected (FFFDh); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value EBh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFFDh) Regularly-spaced frame headers should always be discoverable near EOF. An ID3v1 tag of up to 355 bytes may be present at EOF. The BOF byte sequence represents the MP3 ID3 tag.

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
None
Byte Sequence
494433
Endianness
None
Min Frag Length
Absolute from EOF
Offset
0
Max offset
None
Byte Sequence
FFFD[10:EB]{45-1726}FFFD[10:EB]{45-1726}FFFD[10:EB]{45-1726}FFFD[10:EB]{45-1726}FFFD[10:EB]{7-500}000000{36-1426}
Endianness
None

MPEG-2 Audio Layer II with ID3v2 Metadata Tag (protected)

Note
You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-2, layer II, protected (FFF4h); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value EBh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFF4h) Regularly-spaced frame headers should always be discoverable near EOF. An ID3v1 tag of up to 355 bytes may be present at EOF. The BOF byte sequence represents the MP3 ID3 tag.

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
None
Byte Sequence
494433
Endianness
None
Min Frag Length
Absolute from EOF
Offset
0
Max offset
None
Byte Sequence
FFF4[10:EB]{45-1726}FFF4[10:EB]{45-1726}FFF4[10:EB]{45-1726}FFF4[10:EB]{45-1726}FFF4[10:EB]{7-500}000000{36-1426}
Endianness
None

MPEG-2 Audio Layer II with ID3v2 Metadata Tag (unprotected)

Note
You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-2, layer II, unprotected (FFF5h); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value EBh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFF5h) Regularly-spaced frame headers should always be discoverable near EOF. An ID3v1 tag of up to 355 bytes may be present at EOF. The BOF byte sequence represents the MP3 ID3 tag.

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
None
Byte Sequence
494433
Endianness
None
Min Frag Length
Absolute from EOF
Offset
0
Max offset
None
Byte Sequence
FFF5[10:EB]{45-1726}FFF5[10:EB]{45-1726}FFF5[10:EB]{45-1726}FFF5[10:EB]{45-1726}FFF5[10:EB]{7-500}000000{36-1426}
Endianness
None

Changelog

  • Updated in V109

    Release date
    1 November 2022

    MPEG Audio Stream Layer II: Removed comma from name, updated description, reference links, added relationships and LoC identifier. Submitted by Preservica.

  • Added in V51

    Release date
    15 July 2011

    MPEG Audio Stream, Layer II: Signatures submitted by Georgia Tech Research Institute, USA.