/** @param output Directory, if there will be multiple output files, or a filename.
* @param initial_name Hint that may be used to create filenames, if @ref output is a directory.
* @param include_font true to refer to and export any font file (for Interop; ignored for SMPTE).
/** @param output Directory, if there will be multiple output files, or a filename.
* @param initial_name Hint that may be used to create filenames, if @ref output is a directory.
* @param include_font true to refer to and export any font file (for Interop; ignored for SMPTE).