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Macromedia Flash FLA Project File Format

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name Macromedia Flash FLA Project File Format

Authoring format for Macromedia application software. FLA files typically include vector image data for use in animations, timelines to control animation playback, and audio; they may also include "bitmapped" video content. FLA files may include or reference ActionScripts (similar to JavaScripts) to provide interactivity.1 FLA files are comparable to source code and are typically saved as Flash files for Internet delivery; see SWF_7 and SWF_8.

Temporary note (March 2010): Although Adobe Systems Inc. had acquired Macromedia in 2005, the specification for version 8 of the SWF file format (SWF_8), together with documentation of the FLV format, was published that year under the Macromedia brand. It is not clear to the compiler of this Web page if the specifications for the FLA project format were revised, although in 2005 the creating application was assigned number 8. Specifications for later versions of the Flash file format have been published by Adobe, including version 10 (dated 2008), still available in 2010 from The compilers of this resource hope to update this Website soon to add descriptions of newer versions. Comments welcome.

Production phase Used for initial-state content creation, or for middle-state archiving by producers.2
Relationship to other formats
    May contain Sorenson encoded video.3
    May contain Screen video bitstream format and Screen Video Version 2, not documented here.
    May contain On2 Truemotion VP6 bitstream format, not documented here.
    May contain Raw PCM sampled audio content, not documented here.
    May contain ADPCM, Adaptive Differential PCM Sound Format. Not described on this web site at this time.
    May contain MP3_ENC, MP3 (MPEG Layer III Audio Encoding)
    May contain Nellymoser Asao (speech compression) audio content, not documented here.
    May contain ActionScript as files as external resources1
    Other SWF_7, Macromedia Flash SWF File Format, Version 7. SWF files are typically derived from a FLA file.
    Other SWF_8, Macromedia Flash SWF File Format, Version 8. SWF files are typically derived from a FLA file.

Local use Explanation of format description terms

LC experience or existing holdings None
LC preference None established; it is an interesting question whether FLA ought to be preferred to SWF_7 or SWF_8. Potential challenges to the preservation of SWF files (the offspring of FLA) are discussed in Richard Entlich's article "Flash in the Pan or Around for the Long Haul?". The compilers of this document seek advice regarding preservation preferences: SWF_7 or SWF_8, FLA, a projector version (combines SWF file with runtime player), or is it advisable to archive all three? Comments welcome

Sustainability factors Explanation of format description terms

Disclosure Proprietary, not publicly documented. Developed by Macromedia, Inc., now owned by Adobe Systems.
    Documentation None identified.
Adoption Widely adopted by SWF creators.
    Licensing and patents Details unknown to the compiler of this document.
Transparency Not transparent; proprietary binary format.
Self-documentation Not investigated; likely to be proprietary and associated with the authoring application
External dependencies None.
Technical protection considerations None known to the compilers of this document.

Quality and functionality factors Explanation of format description terms

Moving Image
Normal rendering Good support
Clarity (high image resolution) FLA files feature vector graphics for which high levels of clarity (in some sense) are a given. The conventional video in SWF and FLV files may be compressed in various ways and presumably the same options exist for FLA files (see relationships above). The video quality in these encodings is expected to range from good to very good.
Functionality beyond normal rendering None noted.
Normal rendering Good support
Fidelity (high audio resolution) The SWF specification (and hence the presumed inclusions within FLA files) limits uncompressed audio to 44 kHz sampling and 16 bit words, thus providing very good fidelity. The use of compression will reduce fidelity in accord with the specific encoding and settings selected.
Multiple channels Stereo only.
Support for user-defined sounds, samples, and patches None.
Functionality beyond normal rendering None noted.

File type signifiers Explanation of format description terms

Tag Value Note
Filename extension fla
From The File Extension Source. ActionScript files as external resources carry the as extension.1 The Wikipedia article on Flash (consulted November 30, 2006) includes a list of file types (with extensions) associated with the Flash family.
Internet Media Type Not found.  Comments welcome.   
Magic numbers Hex: D0 CF 11 E0 A1 B1 1A E1 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
From The File Extension Source

Notes Explanation of format description terms

General The File Extension Source calls FLA files "Flash Movie Authoring Files."

Format specifications Explanation of format description terms

Useful references


1 The Web page (consulted November 30, 2006) reports that ".as (or sometimes .actionscript) files contain ActionScript source code in simple source files. FLA files can also contain Actionscript code directly, but separate external .as files often emerge for structural reasons, or to expose the code to versioning applications, and so on." Files with the as extension are simple text files containing ActionScript source code."

2Use as a middle-state format for delivery by producer to publisher is indicated by the following example. The Tribune Entertainment Media Group (consulted November 30, 2006) offers this specification for the submission of advertising: "FLASH files must be received in .FLA format with all font layers located."

3Flash documentation 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: Friday, 13-Sep-2013 14:49:38 EDT