HandBrake

I have a few videos which I previously encoded. Each took at least an hour, some even up to two hours. Back then I didn’t have their subtitle files, however now I do. Is it possible to ‘add on’ subtitles to the output files without having to go through the whole encoding process again? I have tried ...

This isn't a support request. I'm fairly new to the software, trying to familiarise myself with it. For now I use the preset Very Fast 720p30. Each video (~45 min) takes approx. 1 hr to encode. May I know if there is some option whereby multiple encodings can take place at the same time? As of now I...