Only the ss value is required. When the time value does not include a decimal point, the last field is read as the seconds. You can also specify just the seconds. SMIL layout tags can specify a playback region width that overrides the width set here. If word wrap is on, the line length for wrapping corresponds to this width value, not the actual region width.
Text centering, however, corresponds to the actual region width set in the SMIL file.
SMIL layout tags can specify a window height that overrides the height set here. This typically does not adversely affect the presentation, however. The default is black for TickerTape windows and white for all other window types. It has no effect on TickerTape and Marquee windows. The default is 10 for ScrollingNews windows and 0 for all other window types.