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Format

WARC

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Summary

Name
WARC
Identifiers
  • MIME: application/warc
  • PUID: fmt/289
Format type
Aggregate
Description
The WARC (Web ARChive) file format offers a convention for concatenating multiple resource records (data objects), each consisting of a set of simple text headers and an arbitrary data block into one long file. The WARC format is an extension of the ARC file format (ARC) that has traditionally been used to store "web crawls" as sequences of content blocks harvested from the World Wide Web (…) Besides the primary content recorded in ARCs, the extended WARC format accommodates related secondary content, such as assigned metadata, abbreviated duplicate detection events, later-date transformations, and segmentation of large resources”. WARC format has been written by the members of the IIPC (http://www.netpreserve.org/) grouped within the ISO/TC46/SC4/WG12.
Release date
15 May 2009
File extensions
warc
Submitted by
Bibliothèque nationale de France
Supported by
Bibliothèque nationale de France

Relationships

Has lower priority than
Has priority over

Internal signatures

WARC

Description
Matching WARC header. Header: 'WARC/'. Then either 'WARC-Record-ID', 'Content-Length', 'WARC-Type', 'WARC-Date' all madatory fields that can appear in any order.
Provenance
WARC research prompted by format submission from BnF.

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
4096
Byte Sequence
574152432F{0-517}(574152432D5265636F72642D4944|436F6E74656E742D4C656E677468|574152432D54797065|574152432D44617465)
Endianness
None

Changelog

  • V116

    Release date
    23 November 2023

    • Updated

      WARC: Given priority over fmt/101, Extensible Markup Language 1.0. Submitted by Digital Preservation Department, The National Archives (UK) (UK).

  • V97

    Release date
    1 October 2020

    • Updated

      WARC: WARC 1.0 in the v.96, the version number removed and internal signature ammended. Submitted by Landesarchiv Nordrhein-Westfalen.

  • V93

    Release date
    30 November 2017

    • Updated

      WARC: Enhanced description and added compression type as requested by Nationaal Archief, the National Archives of the Netherlands.

  • V69

    Release date
    19 July 2013

    • Updated

      WARC: Improved signature through PRONOM Research.

  • V60

    Release date
    11 June 2012

    • Updated

      WARC: Existing signature refined through PRONOM Research.

  • V42

    Release date
    5 November 2010

    • Added format

      WARC: Full entry added. Submission from Bibliotheque nationale de France.

    • Added signature

      WARC: Signature developed from WARC draft specification