Closed Caption File Format Guide for Netflix
Netflix has two recommended formats. The EMA Closed Captions Working Group has identified Scenarist (.scc) as a preferred format due to its status as the de facto standard for CEA-608 and CEA-708 data. SMPTE-TT is also recommended as, under the applicable laws, it is considered safe if captions are compliant.
Timed Text (.ttml)
Cheetah CAP (.cap)
Quicktime Subtitle (.qt.txt)
Spruce Subtitle File (.stl).