Forum rules
An Activity Log is required for support requests. Please read How-to get an activity log? for details on how and why this should be provided.
SRT is a poorly documented format. SSA actually has documentation.
From messages posted here by the developers over the years, it was apparently decided to standardize on a DOCUMENTED format, instead of a format that, if it works, you're good, but if it doesn't, you probably can't figure out what your did wrong.
To be clear, we are not against SRT passthru support. It's just not high on anyone's priority list and there are lots of other interesting things to do.