Automatic subtitle synchronization

Question

I have subtitles without timing and I need to automatically sync them to a video.

After some searching, I found

• http://www.jaivox.com/wordalign.html
• http://cmusphinx.sourceforge.net/2014/07/long-audio-aligner-landed-in-trunk/
• https://bitbucket.org/natsuhh/prosub/

I would like a recommendation for a software that can sync my subtitles. Preferably based on personal experience.

I have access to Linux and Windows. I prefer offline tool although online is fine too. Video and subtitle formats have no impact: I can convert the video and subtitles into something the aligning tool can work with.

Answer 1

YouTube has an "Automatic timing" feature for transcripts in English, Dutch, French German, Italian, Japanese, Korean, Portuguese, Russian, and Spanish.

https://support.google.com/youtube/answer/2734799?hl=en

Answer 2

Here is anothe way:

1. Load the original videos in the foreign language to Whisper API, or install Whisper LLM locally
2. Let Whisper transcribe the video , return as .srt file. This will contain very precise marks.
3. Paste .srt files into Google Translate or some other translation service
4. Compare the machine-translations with your preexisting translations manually, replace machine translated stuff with manually crafted translations

Update 2024: Google now enforces a 5000 character limit in their translate.google.com web GUI. Stitching together many 5000-character chunks of translated text is possible via the web interface but it is tedious and the results and the "joints" are so-so.