It appears that stl to ssa conversion is mostly related to attempts to convert subtitles from Win 2020 subtitle format (.stl) to SubStation Alpha subtitles (.ssa), something that should be doable with dedicated subtitle editors or even some special subtitle converters.
Convert Win2020 screen subtitle to SubStation Alpha subtitle data.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert stl to ssa on Windows
An online converter for subtitles
Convert from stl file format
|Yes, Subtitle Converter supports stl file conversion as a source file type.||No||No||No||No||No||No||No|
|Yes, Subtitle Converter supports ssa file conversion as a target file type.||No||No||No||No||No||No||No|
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.