Extract DVD subtitle for mkv

[bokbokchui]

I want to create my own SRT subtitles for some HD mkv by extracting subtitles from original DVD source. Here are the tools I used:

1. Use VobSub to extract the English and other lang. of subtitles and convert them to idx/sub
2. Use SubRip 1.2 to OCR the English subtitle as .srt

I know there are some differences of timescale of subtitles for DVD and mkv. However, no matter adjust the .srt subtitle files, say, by adding or subtracting a certain delay, there seems to 100-400 ms out-of-sync when I watch the mkv movie, difference especially large at the end of the movie.

I have tried to convert the frame rate of the SRT from 29.976 (DVD NTSC) to 23.976 (MKV) and it even differs up to minutes and so I think the VobSub timescale FPS should be more or less the same as MKV.

Can anyone know how can I fine tune the final SRT to match the MKV?

Thanks

[sneaker_ger]

There should be no timing adjustments necessary when converting between 29.97 and 23.976 fps. It could be that the DVD and Blu-Ray are cut differently and thus all "simple" methods are bound to fail, with the only solution being to re-time every single line yourself.

[bokbokchui]

How about if the mkv is 24fps?

[sneaker_ger]

You mean true 24.000 fps? Then yes, the timings have to be adjusted in that case.

[setarip_old]

@bokbokchui

Hi!I have tried to convert the frame rate of the SRT from 29.976 (DVD NTSC) to 23.976 (MKV)Try changing from 29.970 (It's not 29.976) to 30.000fps...

[Ghitulescu]

Normally no fps changes are needed when the DVD is NTSC 29.97 and the BD is 23.976. That's what telecine for. Play both movies side by side and you'll see (the duration is also stated on the back cover). However, there is no guarantee that the BD has exactly the same version of the movie, even those that are packed together (BD+DVD) are not 100% corresponding.
I think you have two different cuts there.