syncing subtitles - math help

[maudit]

hi, I have a movie at 25p in the original language on which I'd like to add an eng srt file taken from opensubtitles, (srt framerate is not known)

The first srt line starts at 00:00:29,760.
Its audio starts 0:33.800.

The last srt line start at 01:44:02,620.
Its audio starts 1:39:45.120.

lenght srt = 6242620-29760= 6212860 ms
lenght audio = 5985120-33800= 5951320 ms
delta srt - audio = 6212860-5951320= 261540 ms

Assuming the srt has correct timings, I used this formula in order to stretch the srt in toolnix:

stretch a track by X ms
track_length-X/track_length

so:
srtlenght-261540/srtlenght
6212860-261540/6212860
5951320/6212860
reduced = 297566/310643

using this value, which is very close to the
NTSC > PAL = 960/1001 ratio
and after giving the right delay at the first line,
the result is that both the first and the last srt lines are perfectly in sync with the audio,
while all the lines in the middle are not.

what am i doing wrong?

[maudit]

I cannot understand why this srt is completely out of sync, It does not come from a dvd, is an "home-made" srt,
anyway the movie has an unique version, so I should be able to sync it.
pls help.

[johns0]

Look for the scene changes which occur around every 6-10 minutes and adjust the time up to the first scene change and then repeat for the next scene changes.

[maudit]

Look for the scene changes which occur around every 6-10 minutes and adjust the time up to the first scene change and then repeat for the next scene changes.

ok thanks, I could adjust every line by using Subtitle Edit - Visual Sync, but it's a long work.
I wish I could simply sync the first and the last line to obtain the whole lines in sync, but apparently I cannot.

this is the eng srt: https://www.opensubtitles.org/en/subtitles/6892412/i-viaggiatori-della-sera-en
the movie is easily findable.

It would be helpful to know on which source those 2 guys, the srt authors, have sync it, but it is apparently not possible.

[ProWo]

Use Subtitle Edit.
The english subtitle is probably for a movie with 23.976 fps. So you should first convert this subtitle to a 25 fps subtitle (Synchronization, Change fram rate).


[Attachment 64564 - Click to enlarge]

The subtitle will then start at 28,541 seconds.
Then use (Synchronization, Adjust all times, all lines, show later) with 5.529 seconds to bring it to the desired start time of 33.800.


[Attachment 64565 - Click to enlarge]

Then save the new srt.

[maudit]

Use Subtitle Edit..

thx prowo, I know about that, anyway it can be done with mkvtoolnix "stretch by" and "delay", and it produce the same result.
the problem is that srt is out of sync for some reason I can't get.
as I told before, a NTSC>PAL conversion doesn't work, I can only sync the first and the last line by using the stretch ratio of 297566/310643.
The NTSC > PAL = 960/1001 ratio doesn't work.
Nevermind, I muxed it without eng subs, for some reason the srt doesn't match, maybe cause my video source is from DVB. idk.

[johns0]

You need to sync the 6-10 minutes sections by adjust the first and the last lines in the 6-10 minute scene change and save then got to the next 6-10 minute sections between scene changes,not single lines.

[locotus]

Sometimes I've used this program with relative success with mkv container and movies without singing at the start: https://www.videohelp.com/software/SubSync