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Macromedia Flash SWF File Format, Version 8

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Table of Contents
Identification and description
Local use
Sustainability factors
Quality and functionality factors
File type signifiers
Notes
Format specifications
Useful references
Format Description Properties
• ID: fdd000248
• Short name: SWF_8
• Content categories: moving image
• Format category: file format
• Last significant update: 2007-02-08
• Draft status: Partial

Identification and description Explanation of format description terms

Full nameMacromedia Flash SWF File Format, Version 8
Description

Binary file format that Delivers vector graphics (especially animations) and other data types, including "bitmapped" video, over the Internet to the Flash Player. A more complete format description for Flash is offered for SWF_7, version 7 of the specification.

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.

The October 2005 issue of Macworld magazine reports that the Flash Professional 8 application offers a new video codec called VP6 from a company named On2.

Production phaseUsed for final-state, end-user delivery.
Relationship to other formats 
  Has Earlier Version Macromedia Flash (SWF) Versions 3, 4, 5, and 6, not documented here
  Has Earlier Version SWF_7, Macromedia Flash SWF File Format, Verson 7
  May contain Sorenson encoded video.1
  May contain Screen Video Bitstream Format (ScreenVideo), not documented here.
  May contain Raw PCM sampled audio content, not documented here.
  May contain ADPCM (Adaptive Delta Pulse Code Modulation) audio content
  May contain MP3_ENC audio content
  May contain Nellymoser Asao (speech compression) audio content, not documented here.
  Used by QuickTime File Format
  Other FLA Macromedia Flash FLA Project File Format. Explanatory note: SWF files are typically derived from ("save as") a FLA file.

Local use Explanation of format description terms

LC experience or existing holdingsSee SWF_7
LC preferenceSee SWF_7

Sustainability factors Explanation of format description terms

DisclosureFully documented. Developed by Macromedia, Inc., now owned by Adobe Systems.
  DocumentationThe Macromedia Flash (SWF) and Flash Video (FLV) File Format Specification, Version 8, n.d.(copyright notice 2005). URL active as of February 2007.
AdoptionSee SWF_7
  Licensing and patent claimsAdobe offers the specification and the right to build tools to produce SWF files via a free license.
TransparencyNot transparent; proprietary binary format.
Self-documentationSee SWF_7
External dependenciesNone.
Technical protection considerationsNone known to the compilers of this document.

Quality and functionality factors Explanation of format description terms

Video elements 
Normal rendering for videoGood support
Clarity (support for high image resolution)See SWF_7
Functionality beyond normal rendering for videoSee SWF_7
Sound elements 
Normal rendering for soundGood support
Fidelity (support for high audio resolution)See SWF_7
Support for multiple sound channelsSee SWF_7
Support for downloadable or user-defined sounds, samples, and patchesSee SWF_7
Functionality beyond normal rendering for soundSee SWF_7

File type signifiers Explanation of format description terms

Tag typeValueNote
Filename ExtensionswfFrom the Flash SWF Specification (version 7), p. 9. The Wikipedia article on Adobe Flash (consulted February 2007) includes a list of file types (with extensions) associated with the Flash family.
Internet Media Typeapplication/x-shockwave-flashFrom the Flash SWF Specification, version 7, p. 9.
Internet Media Type application/x-shockwave-flash2-preview
application/futuresplash
image/vnd.rn-realflash
Selected from The File Extension Source
Magic numbersHex: 46 57 53
ASCII: FWS
For uncompressed files; from the Flash SWF Specification, version 8, p. 267. The next byte in the file provides the version number; for example, Hex 07 (0x07) for version 7.
Magic numbersHex: 43 57 53
ASCII: CWS
For compressed files; from the Flash SWF Specification, version 8, p. 267. The next byte in the file provides the version number; for example, Hex 07 (0x07) for version 7.

Notes Explanation of format description terms

GeneralSee SWF_7
HistorySee SWF_7

Format specifications Explanation of format description terms

URLs
The Macromedia Flash (SWF) and Flash Video (FLV) File Format Specification, Version 8 (http://www.adobe.com/licensing/developer/)

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Useful references Explanation of format description terms

URLs
Adobe page regarding licensing (http://www.adobe.com/products/flash/open/licensing/fileformat/license2.html)

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1 Flash documentation for version 8 does not state a number for "their" version of Sorenson but describes the codec as a variant of ITU-T (International Telecommunications Union-Telecommunication Standardization Sector) recommendation H.263 (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.


Last Updated: 03/ 7/2007