Structured Subtitles Format

SSF (Structured Subtitles Format), much like USF is an  XML based subtitle format developed by Gabest. It also borrows ideas from  Cascading Style Sheets. It's expected to be fully supported by the next release of MPC and VSFilter. However, there are no programs that support editing in that format.

The format has received a lot of criticism for its extreme verbosity in order to accomplish simple tasks, which makes it unpractical to write by hand. Aegisub has no support for this format, and it most likely won't unless high interest is shown in it.

•  ssf-specs.txt - the little documentation there is on the format. Specifies syntax but not semantics.