Sustainability of Digital Formats
 Planning for Library of Congress Collections

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AVI

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name AVI (Audio Video Interleaved)
Description File format for moving image content that wraps a video bitstream with other data chunks, e.g., audio.
Production phase Often a middle-state format, e.g., the video source when producing lower-resolution streaming versions; sometimes a final state format for enduser delivery.
Relationship to other formats
    Subtype of RIFF, Microsoft Resource Interchange File Format
    Has subtype AVI_Cinepak, AVI, Cinepak Codec
    Has subtype AVI_DivX, AVI, DivX codec
    Has subtype AVI_DV, AVI, DV Digital Video
    Has subtype AVI_Indeo, AVI, Indeo Codec
    Has subtype AVI_MJPEG, AVI, MJPEG Codec
    Has subtype AVI_J2K, AVI, JPEG 2000 Codec
    Has subtype AVI files containing streams produced by other video codecs, including uncompressed and lossless video, not documented at this time.
    Has subtype AVI_OpenDML (format extensions). Not documented at this time.
    May contain WAVE, WAVE Audio File Format
    May contain MP3_CBR, MP3 Audio Encoding, Constant Bit Rate

Local use Explanation of format description terms

LC experience or existing holdings American Memory produced AVI_Indeo files in 1992 and 1993, using version 3.1 or 3.2 of the Indeo codec, at 15 fps and 320x240 pixels, and yielding a data rate of about 188 Kb/s. These AVI files were retired and replaced by MPEG-1 and QuickTime files in 1994 and 1995.
LC preference For preservation reformatting, the Library of Congress' Packard Campus for Audio-Visual Conservation has chosen losslessy-compressed JPEG 2000 encoded video wrapped in MXF. In 1992 and 1993, American Memory produced AVI_Indeo at 15 fps and 320x240 pixels. These files were retired and replaced by other formats beginning in 1994.

Sustainability factors Explanation of format description terms

Disclosure

Fully documented. Proprietary file format developed by Microsoft and IBM as part of RIFF, the Resource Interchange File Format for Windows 3.1.

For information about the disclosure of information about the bitstreams wrapped by AVI, see the descriptions of individual codecs listed under Relationships, above.

    Documentation

Specifications available from third parties; for example, the Multimedia Programming Interface and Data Specifications 1.0 (Issued as a joint design by IBM Corporation and Microsoft Corporation, August 1991), is available online from http://www.kk.iij4u.or.jp/~kondo/wave/mpidata.txt and other sites. Additional information may be found at John McGowan's AVI Overview (http://www.jmcgowan.com/avi.html) and http://www.opennet.ru/docs/formats/avi.txt. Documentation of the OpenDML extensions available from Morgan Multimedia (http://www.morgan-multimedia.com/download/odmlff2.pdf). Some additional citations in Useful references below.

Adoption

Widely adopted for video production and filemaking. Adoption may not extend to all permitted codecs and other features.

One commentator wrote in 2000 that the introduction of Microsoft's Advanced System Format or ASF had "pushed to one side" the OpenDML effort, which dates from 1996-97. At the time of this writing (2011), the National Archives and Records Administration (NARA) uses AVI as the preservation master format for their reformatted video materials. For more information see NARA's Digitization Products and Services.

    Licensing and patents [Unknown, probably none]
Transparency

See information on the codecs incorporated in AVI files: MJPEG, Indeo_3, Indeo_5, Cinepak, and DivX_5.

Self-documentation

Technical information in header chunks (e.g., hdrl, movi, and others); descriptive metadata may appear in a RIFF INFO chunk.

External dependencies None
Technical protection considerations None

Quality and functionality factors Explanation of format description terms

Moving Image
Normal rendering Good support.
Clarity (high image resolution)

Moderate to good, given that this is a format typically used for compression and that most implementations do not support interlaced video. Outcome will depend on the type and level of compression, and the encoder used. Extent of use of uncompressed video bitstream unknown. High resolution work is limited in the Windows environment due to file size limits (2 GB with FAT 16 technology; theoretical 8 GB with later technologies).

The OpenDML extensions were intended to increase quality in professional applications by supporting the representation of interlaced video (60 fields per second), 24 fps for content from motion picture film, and other features.

Functionality beyond normal rendering Good to excellent, given that the options for audio are those available in the MP3_CBR and WAVE formats.

File type signifiers Explanation of format description terms

Tag Value Note
Filename extension avi
 
Internet Media Type video/vnd.avi
From http://www.iana.org/assignments/wave-avi-codec-registry/wave-avi-codec-registry.xml. No examples found in IANA MIME Media Types.
Internet Media Type video/avi
video/msvideo
video/x-msvideo
image/avi
application/x-troff-msvideo
audio/avi
Selected from The File Extension Source.
Magic numbers Hex: 52 49 46 46 xx xx xx xx 41 56 49 20 4C 49 53 54
ASCII: RIFF....AVILIST
From Gary Kessler's File Signatures Table.
Microsoft FOURCC Not applicable.  Varies according to the video codec selected; see, for example the archived version of the Microsoft registry mounted by IANA.
Microsoft WAVE format registry Not applicable.  Varies according to the video codec selected; see, for example the archived version of the Microsoft registry mounted by IANA.

Notes Explanation of format description terms

General  
History Format created by Microsoft and introduced with Windows 3.1. In its first version, picture size was limited to 160x120 pixels and 15 frames per second; over time, capabilities were extended to larger picture sizes and higher frame rates.

Format specifications Explanation of format description terms


Useful references

URLs


Last Updated: 10/23/2013