.FLA File Format – The library

XFL document (Flash CS5 and later, ZIP)

The library holds everything a document can place on the stage more than once: symbols drawn in Flash, and imported bitmaps, sounds, videos, fonts and compiled clips. Symbols are files of their own in LIBRARY/, listed by <Include> in DOMDocument.xml’s <symbols>. The other items are elements in DOMDocument.xml itself, in <media> and <fonts>, and point at their data in bin/. An item’s name includes its library folder, such as Assets/Other/minimap.png.

Symbol items

Each symbol file in LIBRARY/ has the root element <DOMSymbolItem>:

Attribute or childMeaning
nameThe symbol’s name, with its folder path.
itemIDIts identifier, the same as in the <Include> that lists it.
symbolTypegraphic or button; a movie clip when the attribute is absent.
lastModifiedWhen it last changed, as a number.
linkageExportForAStrue when the symbol is exported for ActionScript (below).
linkageClassNameThe ActionScript class it is linked to.
linkageBaseClassThe class that class extends, such as flash.display.Sprite.
source-link attributesBy their names, for a symbol kept up to date from one in another document.
<timeline>The symbol’s own <DOMTimeline>, laid out like a scene’s; see Timelines, layers and frames.

Bitmap items

A <DOMBitmapItem> in <media> is an imported image:

AttributeMeaning
nameThe item’s name, with its folder path.
hrefA file name for the item.
bitmapDataHRefThe file in bin/ with the bitmap in Flash’s form, such as M 31 1372941248.dat; see Bitmaps in bin/.
frameRight, frameBottomThe width and height in twips: divide by 20 for pixels.
isJPEGtrue when the .dat file is a JPEG.
quality, compressionTypeBy their names, how the bitmap is to be compressed when the SWF is published.
source attributesThe path of the file it was imported from, and a CRC.

The explorer shows the first few bitmaps of a document, each titled with its name and the size in pixels that frameRight and frameBottom give.

Sound items, video and fonts

  • <DOMSoundItem> – an imported sound, in <media>. Its attributes are not described here; the explorer lists the item but does not play it.
  • <DOMVideoItem> – an imported video, in <media>.
  • <DOMCompiledClipItem> – a compiled clip or component, in <media>: linkageClassName and actionscriptClass name its class, and swfScmHRef names the SWF that holds it in bin/.
  • <DOMFontItem> – a font symbol, in <fonts>: font is the font’s name, size its size, and embedRanges the ranges of characters to embed.

ActionScript linkage

A symbol exported for ActionScript has linkageExportForAS="true" and a class name in linkageClassName. When the SWF is published, the symbol becomes an instance of that class. The class itself is not in the document: Flash looks for an .as file of that name on the class path (so game.Enemy would be game/Enemy.as), and when there is none it generates a class that simply extends linkageBaseClass. A compiled clip’s class is already compiled, inside its SWF.

The explorer lists every linkage class in its Classes table, with the symbol it belongs to, its base class and the .as file it would be in. See ActionScript in FLA.