Aren't Subtitles Based on Time?

[Spiffy577]

Hello,

I have multiple video files with subs that slowly go out of sync. It seems it's because the subtitle file has a different framerate than the video. But aren't subtitle files based on time codes, not frames? I'm confused. Any easy way to fix them? I had one online source that I could upload the subtitles file and change the fps rate gradually until it worked but that was a pain. Plus, it took an hour. I have a lot of videos.

Thanks,
Josh

[Ennio]

Subtitle Edit has a tool onboard for syncing subsitles. In it's main editing window, you'll find it in the upper menu bar called "Synchronization". Syncing can done in different ways, one of them being "by framerate".

Syncing image-based subs can be done in SE's SUP editor. Such sourcefiles can be loaded by going File --> Import --> Blu-ray (.sup) subtitle file for edit.

[EDIT] As to your initial question, whether subtitles are based on time or frame, there is always an academical relation between the two: framerate.

Subs going out of sync is often caused by a difference between the native framerates of subtitles and target video.
A much occurring example is where subtitles that origin from 23.976 fps video, are combined with exact 24fps video. Or vice versa. You can imagine that the more these two framerates differ, the faster async will be.