the process of typing the spoken word (from a TV sportscaster, say) which TV viewers can see if they have activated the Captions option?
Someone here used “transliterate” to describe this, but according to Merriam-Webster online, that word means “to represent or spell in the characters of another alphabet.”
Captioners “transcribe” the voice to text. At least, that’s what they say they do when they call my company for software support (the company develops captioning and court reporting software).
IIRC a captioner I knew simply called it ‘captioning’, as in “I’m going to caption Casablanca next week”. It’s obviously not the correct technical name for it, but I don’t think she ever referred to it as ‘transcribing’ when speaking informally.