MACROMEDIA FLASH 8-COMPONENTS LANGUAGE Reference page 529

Most of the buttons, as supplied, are based on a common set of movie clips so that you can
change the appearance of all the buttons at once. You can use this capability, or you can
replace those common clips and make every button look different.
BufferingBar component
The buffering bar component is simple: It consists of an animation that is made visible when
the component enters the buffering state, and it does not require any special ActionScript to
configure it. By default, it is a striped bar moved from left to right with a rectangular mask on
it to give it a "barber pole" effect, but there is nothing special about this configuration.
Although the buffering bars in the skin SWF files use 9-slice scaling because they need to be
scaled at runtime, the BufferingBar FLV Custom UI Component does not and cannot use 9-
slice scaling because it has nested movie clips. If you want to make the BufferingBar wider or
taller, you might want to change its contents rather than scale it.
SeekBar and VolumeBar components
The SeekBar and VolumeBar components are similar, although they have different functions.
Each has handles, uses the same handle tracking mechanisms, and has support for clips nested
within to track progress and fullness.
There are many places where the ActionScript code in the FLVPlayback component assumes
that the registration point of your SeekBar or VolumeBar component is at the upper-left
corner of the content, so it is important to maintain this convention. Otherwise, you might
have problems with handles and with progress and fullness movie clips.
Although the seek bars in the skin SWF files use 9-slice scaling because they need to be scaled
at runtime, the SeekBar FLV Custom UI component does not and cannot use 9-slice scaling
because it has nested movie clips. If you want to make the SeekBar wider or taller, you might
want to change its contents rather than scale it.
Handle
An instance of the handle movie clip is on Frame 2. As with the BackButton and
ForwardButton components, the component never actually goes to Frame 2; these movie clips
are placed here to make editing more convenient and as a way to force them to be loaded into
the SWF file without checking the Export in First Frame check box in the Symbol Properties
dialog box. You still must select the Export for ActionScript option, however.
Customizing the FLVPlayback component 527