FFsubsync
ffs video.mp4 -i unsynchronized.srt -o synchronized.srt
ffsubsync reference.srt -i unsynchronized.srt -o synchronized.srt
Flowershow Cloudffs video.mp4 -i unsynchronized.srt -o synchronized.srt
ffsubsync reference.srt -i unsynchronized.srt -o synchronized.srt