Sustainability of Digital Formats: Planning for Library of Congress Collections
Sustainability of Digital Formats: Planning for Library of Congress Collections |
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| Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact | |
| Full name | Macromedia Flash SWF File Format, Version 7 |
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| Description |
SWF, pronounced /swɪf/ or 'swiff', is a defunct format for multimedia content in the Adobe Flash Player. Information on this page was current at time of initial writing. Adobe announced End of Life (EOL) for the Adobe Flash Player on December 31, 2020 and" blocked Flash content from running in Flash Player beginning January 12, 2021." Delivers vector graphics (especially animations) and other data types, including "bitmapped" video, over the Internet to the Macromedia Flash Player. Commentators describe the technology as "non-native" to the Web. Very simple playback (with a repeat loop) is controlled by a timeline; interactive examples (even very simple ones) use both a timeline and ActionScript, a scripting language similar to JavaScript. ActionScripts may reference objects within the SWF file or resources external to it, e.g., Macromedia FLV video files. SWF files are typically derived from a FLA file (Macromedia Flash Project File); they may also be produced in other ways using third-party software. SWF files may be combined with a runtime version of the Flash player, resulting in a file type called projector. Windows versions of projector files are executables with an exe extension. The swf extension was originally used for files played by Macromedia's Shockwave browser plug-in; see Notes for additional history information. In 2005, Adobe purchased Macromedia and a branding changeover began. The documentation for the Flash (SWF) format, version 8, was disseminated from the Adobe Web site but still carried the Macromedia brand on the cover sheet. |
| Production phase | Used for final-state, end-user delivery. |
| Relationship to other formats | |
| Subtype of | SWF_Family, Macromedia Flash SWF File Format Family |
| Has later version | SWF_8, Macromedia Flash SWF File Format, Version 8 |
| LC experience or existing holdings | The Library of Congress has over 185,000 Flash files in its collections as of May 2024. Version of Flash is unknown. |
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| LC preference | See the Library of Congress Recommended Formats Statement for format preferences for moving image works. Potential challenges to the preservation of SWF files are discussed in Richard Entlich's article "Flash in the Pan or Around for the Long Haul?". |
| Disclosure | See SWF_Family. |
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| Documentation | The specification for Macromedia Flash (SWF) File Format Specification Version 7 version 7 (2002-2003). |
| Adoption | See SWF_Family |
| Licensing and patents | See SWF_Family |
| Transparency | See SWF_Family |
| Self-documentation | See SWF_Family |
| External dependencies | See SWF_Family |
| Technical protection considerations | See SWF_Family |
| Moving Image | |
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| Normal rendering | See SWF_Family. |
| Clarity (high image resolution) | See SWF_Family. |
| Functionality beyond normal rendering | See SWF_Family |
| Sound | |
| Normal rendering | See SWF_Family. |
| Fidelity (high audio resolution) | See SWF_Family. |
| Multiple channels | See SWF_Family. |
| Support for user-defined sounds, samples, and patches | See SWF_Family. |
| Functionality beyond normal rendering | See SWF_Family. |
| Tag | Value | Note |
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| Filename extension | See related format. | See SWF_Family. |
| Internet Media Type | See related format. | See SWF_Family. |
| Magic numbers | Hex: 46 57 53 ASCII: FWS |
For uncompressed files; from the Flash SWF Specification, version 7, p. 10. The next byte in the file provides the version number; Hex 07 (0x07) for version 7. |
| Magic numbers | Hex: 43 57 53 ASCII: CWS |
For files compressed with ZLIB; from the Flash SWF Specification, version 7, p. 10. The next byte in the file provides the version number; Hex 07 (0x07) for version 7. |
| Other | NF00243 |
See https://www.archives.gov/files/lod/dpframework/id/NF00243.ttl for Macromedia Flash 7. |
| Pronom PUID | fmt/110 |
See http://www.nationalarchives.gov.uk/PRONOM/fmt/110 for Macromedia Flash version 7 |
| Wikidata Title ID | Q29011358 |
See https://www.wikidata.org/wiki/Q29011358 for Shockwave Flash, version 7. |
| General | See SWF_Family. |
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| History | See SWF_Family. |
1 Flash documentation for version 7 does not state a number for "their" version of Sorenson but describes the codec as a variant of ITU-T (International Telecommunications Union) recommendation H.263 (See MPEG-4_V). In early 2006, one of Sorenson's compression applications to produce content for Flash offered the Sorenson_3 codec, described by experts as a variant of ITU-T H.264 (MPEG-4_AVC). By late 2006, Sorenson offered new compression applications with other outputs.
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