relativeSize
A factor on the size the text would otherwise have, from fontSizePx or the renderer's default, as a WebVTT stylesheet's font-size: 120% gives one. 1 leaves the size alone.
A factor on the size the text would otherwise have, from fontSizePx or the renderer's default, as a WebVTT stylesheet's font-size: 120% gives one. 1 leaves the size alone.