An alternative to reCAPTCHA...still not perfect. It could trip up someone with cognitive disabilities..or pretty much anyone having an off day. But perhaps it's better than asking a blind user to remember an 8 digit sequence with JAWS talking over the recording and having to repeatedly enter/exit forms mode? It could be edited to include an easier sequence which would make it even more accessible for everyone except spambots.
YouTube clips have previously allowed for captioning, but it was a system that was a little buggy and only worked from YouTube's site. That's all changed with the advent of machine-generated captions and auto-timing.