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DVD Authoring: Reference
Why Subpictures?
Subpictures are superimposed on the video and can be used on a DVD for such things as subtitles and
overlays as well as for menu button highlights. Even when created in a graphics program, a subpicture
does not really have its “owncolors; the colors are assigned dynamically as soon as the subpicture is
played in the DVD player. This assignment (mapping) of color and transparency is performed on the
Highlight tab.
According to the DVD specification, there are four pixel types. Only these four types are used to create
subpictures. The following are the names of these types as per the specification plus the designation used
by Avid Liquid:
Background / Color 1
Emphasis 1 / Color 2
Emphasis 2 / Color 3
Foreground / Color 4
These designations should not be taken literally and in other DVD authoring programs are referred to by
different names such as “Red/Green/Blue”, “Color Map #1”, etc. The designations do not necessarily
have anything to do with “background” or “emphasis”.
Each pixel type has a color from a palette of 16 colors and a degree of transparency that is also one of 16
degrees ranging from fully transparent to opaque. Each menu is checked to determine which colors and
degrees of transparency are assigned to which pixel type. Thus, the same subpicture can appear differ-
ently from menu to menu, at least as far as its color is concerned.