I can't believe this isn't an option yet. Every other channel I use for promoting video content defaults to .srt files for captions, it's absolutely crazy that I have to create a completely separate file for MS Stream.
This won't be done for Stream classic at this point but since we are actively building captions and transcripts into SharePoint and onedrive please add this feature request to our new idea feedback portal:
Https://aka.ms/streamideas
