Adobe 65008009 - After Effects CS4 Using Manual page 713

Last updated 12/21/2009
When After Effects creates an XFL file, it also saves a report ([XFLfile_name] report.html) to the same folder as the
XFL file. The report indicates the following:
• whether layers with unsupported features were rasterized or ignored
• whether each source item was rasterized ("rendered") or passed through ("linked")
• whether each layer was rasterized ("rendered") or converted to a native Flash object
Working in Flash Professional with a FLA document created from an XFL file
The Library panel in Flash Professional is similar to the Project panel in After Effects. When Flash Professional creates
a FLA document from an XFL file, it creates symbols, folders, and video clips and organizes them in the Library panel.
Each item in the Library panel has a unique name—even if they are based on items with identical names in After
Effects—so that these items can be manipulated using ActionScript. This requirement for unique naming causes After
Effects to append underscore characters and numerals to many names when creating the XFL file.
When Flash Professional builds a FLA document from an XFL file that includes FLV files, the FLV files are embedded
in the timeline in Flash. Often, a more efficient way to construct a FLA document is to move the video files to an
external location referenced by the SWF file to stream the video. You can unembed FLV files as appropriate within
Flash Professional, by deleting the video and importing it again using the FLVPlayback component.
Note: In After Effects, the composition's timeline begins at frame 0. In Flash Professional, the timeline begins at frame 1.
This difference causes the After Effects composition timeline and the corresponding Flash timeline to appear to be offset
from one another by one frame.
In After Effects, a composition can have pixel aspect ratios other than 1.0 (square pixels). Flash Professional only
supports a pixel aspect ratio of 1.0. When a composition is exported to XFL format, the FLA document is a square-
pixel document with a different number of pixels so that the appearance of the document in Flash Professional matches
the appearance of the composition in After Effects. Scale values in the XFL file preserve the appearance of the layers.
How features and data are preserved when exporting a composition to XFL format
When a composition is exported as an XFL file, After Effects goes through multiple stages, attempting at each stage to
export the maximum amount of information from layers and their source files.
If the composition uses PNG, JPEG, and FLV files as the sources for its layers, these source files are included in the
XFL output (passed through) unless the layers use features that force After Effects to transcode the source files or
rasterize the layers for export to XFL.
Note: Transcoding is the conversion of a source file from one format to another format, such as from GIF to PNG.
Rasterizing is the conversion of a layer to a bitmap image, incorporating all of the model information—such as vectors
and keyframes—into a flattened, pixel-based image for each frame.
Stage 1: Source files are passed through unchanged, if possible.
For a layer's source file to be passed through to the XFL file, the layer must meet these requirements:
• The layer has a source footage item, and that footage item uses a PNG or JPEG sequence or FLV file as its source.
(The layer is not a text layer, camera layer, light layer, or shape layer.)
• The source footage item's frame rate matches the composition's frame rate.
• The layer's source is not trimmed.
• The layer does not extend before the first frame or after the last frame of the composition work area.
• The layer has no properties other than Position, Anchor Point, Opacity, Scale, and Rotation. Because effects add
properties to layers, this requirement also means that the layer has no effects applied.
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USING AFTER EFFECTS CS4
Rendering and exporting