MACROMEDIA FLASH 8-COMPONENTS LANGUAGE Reference page 535

Although layout_mc looks a lot like how the skin will look like at runtime, the contents of
this clip are not visible at runtime. It is used only to calculate where to place the controls. The
other controls on the Stage will be used at runtime.
Within layout_mc is a placeholder for the FLVPlayback component named video_mc. All the
other controls are laid out relative to video_mc. If you start with one of the Flash 8 FLA files
and change the size of the controls, you can probably fix the layout by moving these
placeholder clips.
Each of the placeholder clips has a specific instance name. The names of the placeholder clips
are: playpause_mc, play_mc, pause_mc, stop_mc, back_mc, bufferingBar_mc, seekBar_mc,
volumeMute_mc, and volumeBar_mc.
Which clip is used for a control is not important. Generally, for buttons the normal state clip
is used. For other controls the clip for that control is used, but this is only for convenience. All
that is important are the x (horizontal) and y (vertical) location and the height and the width
of the placeholder.
You can also have as many background and foreground clips as you want besides the standard
controls. You must use the following naming convention, however: bg1_mc, bg2_mc, and so
on for background clips; and fg1_mc, fg2_mc, and so on for foreground clips. You cannot
skip numbers. For example, if you have bg1_mc and bg3_mc but no bg2_mc, bg3_mc will
not be used. This scheme is designed to put background clips behind the controls, with
bg1_mc on the bottom and bg2_mc above it, and the foreground clips above the controls,
with fg1_mc first and fg2_mc above fg1_mc, and so on. However, the layered relationship of
the clips is actually determined by the ordering of the corresponding controls on the Stage, so
make sure that is correct.
The bg1_mc clip is special. If you set the property to the
FlvPlayback.skinAutoHide true,
skin shows when the mouse is over the bg1_mc clip. This is important for skins that appear
outside the bounds of the video player. For information on the property, see
skinAutoHide
"Modifying skin behavior" on page 538.
In the Flash 8 FLA files, bg1_mc is used for the chrome, and some use bg2_mc for the border
around the Forward and Back buttons.
ActionScript
The following ActionScript code applies to all controls generally. Some controls have specific
ActionScript that defines additional behavior, and that is explained in the section for
that control.
Customizing the FLVPlayback component 533