Any good software for adding permanent subtitle to a mp4 video?

Hello I'm looking for a paid or non paid software to add hardcoded subtitles to a mp4 video without loosing quality and without exceeding the size of the video. Im currently using ripbot264 but Im unable to change the font, style or the size of my subtitles and It changes the video size for example the video before encoding is 800mb after encoding goes to 1.2gb or even more. Hope anybody helps me finding a software or a tutorial that fits my requirements. :)

Regards
ANi