 Usually, performance is affected because the font file can be large and take time to load for the subtitles.The DivX Plus Word Fonts extension attempts to solve this problem by optimizing the font file during the file creation stage.A DivX Plus mux, like the DivXMKVMux, can examine the subtitle file, determine which characters are required from a font file, and repack the font file for attachment with only the necessary symbols, thereby reducing the font attachment size and decreasing the time it needs to load.