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:

• AIFF 1.3 [AIFF]
• AIFF-C [AIFF-C]

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)