As much as I’m fond of my collection of Matroska files with SSA/ASS subtitle tracks, I don’t think those are appropriate for the Web, what with all the font issues; and SRT is a nightmare of encodings. But apparently there’s a WebM-blessed way[1] of embedding WebVTT ( = SRT + UTF-8 − decimal commas) now? Which is of course different[2] from the more recent Matroska.org-blessed way[3], sigh.

[1] https://www.webmproject.org/docs/container/#webvtt-guideline...

[2] https://trac.ffmpeg.org/ticket/5641

[3] https://matroska.org/technical/codec_specs.html#s_textwebvtt

> I don’t think those are appropriate for the Web, what with all the font issues

Fun fact: several broadcast standards use Bitstream TrueDoc Portable Font Resource, which was supported for embedded web fonts way back in Netscape 4:

https://people.apache.org/~jim/NewArchitect/webrevu/1997/11_...

https://web.archive.org/web/20040407162455/http://www.bitstr...

“The PFR specification defines the Bitstream portable font resource (PFR), which is a compact, platform-independent format for representing high-quality, scalable outline fonts.

Many independent organizations responsible for setting digital TV standards have adopted the PFR font format as their standard font format, including:

— ATSC (Advanced Television Systems Committee)

— DAVIC (Digital Audio Visual Council)

— DVB (Digital Video Broadcasting)

— DTG (Digital TV Group)

— MHP (Multimedia Home Platform)

— ISO/IEC 16500-6:1999

— OCAP (OpenCable Application Platform)”

All text based subtitles share the (non-)issue of encoding. Nothing wrong with SRT, it's UTF8 in Mkv anyway.