AIFF-hul Module

Introduction

The AIFF-hul module recognizes and validates the Audio Interchange File Format (AIFF) [AIFF]. The AIFF format is itself a profile of the Electronic Arts IFF 85 format [IFF].

The module is invoked by the:

jhove ... -m AIFF-hul ...

command line option.

2 Coverage

The AIFF-hul module recognizes and validates the following public profiles:

3 Well-Formedness

The following criteria must be met by an AIFF object for JHOVE to consider it well-formed:

  • Magic number: “FORM” at byte offset 0; “AIFF” (for AIFF) or “AIFC” (for AIFF-C) at offset 8
  • One Form chunk containing one Common chunk and at most one Sound Data chunk (if numSampleFrames > 0)
  • At most one instance of each of the following optional chunks: Marker, Instrument, Audio Recording, Comments, Name, Author, Copyright
  • All chunks required by a given profile exist in the file
  • All chunk structures are well-formed: a four ASCII character ID, followed by a 32 signed integer size, followed by a size byte data block (if size is odd, then the data block includes a final padding byte of value 0x00)
  • No data exist before the first byte of the chunk or after the last byte of the last chunk

4 Validity

The following criteria must be met by an AIFF file for JHOVE to consider it valid:

  • The file is well-formed

5 Representation Information

The MIME type is reported as: audio/x-aiff.

In addition to the standard JHOVE representation information, the following AIFF-specific properties are reported:

  • Property “AIFFMetadata” of type PROPERTY and arity ARRAY
    • Properties capturing the technical attributes of the AIFF image from all chunks

The AIFF module reports audio technical properties using the draft AES-X098B, Core audio metadata XML definition, currently under development by the Audio Engineering Society (AES) SC-03-06 Working Group on Digital Library and Archive Systems.

5.1 Profiles

AIFF 1.3

AIFF is an interchange format for sampled monaural or multichannel sampled sounds using a variety of sample rates and widths.

Profile requirements include:

  • The Form chunk identifier is “AIFF”

AIFF-C

AIFF-C is an extended AIFF format that can contain compressed audio data.

Profile requirements include:

  • The Form chunk identifier is “AIFC”

  • The fields compressionType and compressionName in the Common Chunk

    Common compression types and names include, but are not limited to:

    Type Name Note
    “NONE” “Not compressed” PCM data
    “ACE2” “ACE 2-to-1” Apple IIGS ACE (Audio Compression/Expansion)
    “ACE8” “ACE 8-to-3”  
    “APD4” “4:1 Intel/DVI ADPCM” SoundHack
    “ALAW” “CCITT G.711 A-law” SGI 8-bit ITU-T G.711 A-law (64 kb/s)
    “alaw” “ALaw 2:1” Apple 8-bit ITU-T G.711 A-law
    “DWVW” “Delta With Variable Word Width” Yamaha TX16W Typhoon sampler
    “FL32” “Float 32” SoundHack / CSound IEEE 32-bit floating point
    “fl32” “32-bit floating point” Apple IEEE 32-bit floating point
    “fl64” “64-bit floating point”  
    “ima4” “IMA 4:1”  
    “MAC3” “MACE 3-to-1” Macintosh Audio Compression/Expansion
    “MACE6” “MACE 6-to-1”  
    “QDMC” “QDesign Music” QDesign Music codec
    “Qclp” “QualComm PureVoice” QualComm PureVoice codec
    “rt24” “RT24 50:1” Voxware codec
    “rt29” “RT29 50:1”  
    “ULAW” “CCITT G.711 µ-law” SGI 8-bit ITU-T G.711 µ-law (64 kb/s)
    “ulaw” “µLaw 2:1” Apple 8-bit ITU-T G.711 µ-law
  • One Format Version chunk

6 Additional Module Properties

  • Nominal file extension: .aif
  • Nominal file extension: .afc (for the AIFF-C profile)