[smacke]

Great question. The main use case I can think of is when reference.srt and unsynchronized.srt are in different languages, and you want to eventually merge them into a single dual-language subtitle file.

EDIT: Oh, I should also mention that you don't need a reference.srt -- it can look at the video directly and use that as a reference.

[kojackst]

Ohh now I got you. I believe README should be improved in this part then.

It reads:

====

Although it can usually work if all you have is the video file, it will be faster (and potentially more accurate) if you have a correctly synchronized "reference" srt file, in which case you can do the following:

subsync reference.srt -i unsynchronized.srt -o synchronized.srt

====

I believe you should explain that if you have a reference file in another language which is correctly synchronized with that video, you can use that file instead of the video, as its timestamps will serve as references when synchronizing the target .srt file.

Now this has raised a question, what if the reference file has a different block count? For example, in some languages (like Chinese or Japanese) we can say a lot with fewer characters than in English. So in Chinese a text will stay on the screen for a long time, whereas in English the corresponding text would be split into two or more blocks. Wouldn't that make synchronization less accurate?

BTW that's a cool project. Thanks for sharing!

[smacke]

Really appreciate the feedback -- will definitely work on improving the clarity in the README. Glad you like the project!

[smacke]

Sorry, I forgot to answer your last question. It turns out that, because of how the algorithm works, the number of blocks shouldn't matter. Since it is discretizing time windows in 10ms increments, the granularity of the "effective blocks" is small enough that putting two separate large blocks on the screen, each for a shorter period of time, is roughly equivalent to putting a single large block on the screen for twice as long (for synchronization purposes, that is).

[aasasd]

> when reference.srt and unsynchronized.srt are in different languages

I just want to thank you for including this use-case, because it's exactly the thing I'm regularly running into. Subs in one language are bundled with the vid, all subs from OpenSubtitles are desynchronized.

[smacke]

You are most welcome! This is exactly the use case I was initially targeting; I got super lucky that the VAD-based synchronization happened to be low-hanging fruit that has a higher "Wow" factor.

[zeotroph]

Given it just processes audio, how long does processing one video file usually take?

[smacke]

Audio extraction is actually the most expensive part. It depends on the length of the video, but my experience is that it finishes in 20 to 30 seconds. It's possible one might be able to sample different parts of the video to bring the runtime down further; I plan to experiment with this when I get the chance.