Credit: https://www.w3.org/WAI/WCAG21/Techniques/#smil
- SM1: Adding extended audio description in SMIL 1.0
- SM2: Adding extended audio description in SMIL 2.0
- SM6: Providing audio description in SMIL 1.0
- SM7: Providing audio description in SMIL 2.0
- SM11: Providing captions through synchronized text streams in SMIL 1.0
- SM12: Providing captions through synchronized text streams in SMIL 2.0
- SM13: Providing sign language interpretation through synchronized video streams in SMIL 1.0
- SM14: Providing sign language interpretation through synchronized video streams in SMIL 2.0