A fast way to split both a video and its subtitle then integrate the subtitle back into the new segment
(sometimes you may encounter a weird behavious where the output video starts before 5 seconds than specified in the -ss parameter)
ffmpeg -ss 00:00:14.500 -i input.mp4 -t 00:17:05.500 -c copy d:\_ffmpeg_output\output.mp4
ffmpeg -ss 00:00:14.500 -copyts -i input.mp4 -to 00:17:20.0 -c copy d:\_ffmpeg_output\output.mp4
ffmpeg -ss 00:00:14.500 -i input.srt -t 00:17:05.500 d:\_ffmpeg_output\output.srt