I noticed a lot of video having pre-render captions. I remember I saw someone working in a Chinese studio that primarily does translation works and she was using a software to render the SRT or ASS file to raw videos automatically. I thought it was very convenient and wonder if anyone knows how it was done.
Adobe Premiere Pro allows you to create caption files (including SRT) and export them individually (as SRT files) or embedded with the actual video. This link gives a pretty good overview of how it's done in Premiere.