Starts too soon, but ends OK

[queensoft]

Starting times are too early. But not all lines start too early with the exact same delay.
Sometimes 0.5 seconds too early, sometimes start is OK.
End times are always OK.
So, is there a program / an option to change durations based on end times, not on start times?
Thanks.

[betwixt]

I'm afraid my crystal ball needs polishing.
What starts too early?
Is this a video file, audio file or something else?
What editor or player are you using?
What should the end time be?

Brian.

[queensoft]

Subtitles. We're in the subtitle section.
Subtitles lines start too soon. But they end OK.
Start time should be later, based on duration - simplest way is, let's say, 15% later / shorter duration.
End time should be unchanged.

[ProWo]

Subtitles. We're in the subtitle section.
Subtitles lines start too soon. But they end OK.
Start time should be later, based on duration - simplest way is, let's say, 15% later / shorter duration.
End time should be unchanged.

Extract the subtitle, correct the timings with subtitle edit and remux the corrected subtitle back.

[queensoft]

Let's assume I have the subtitle. SRT format, SRT file.
Let's assume remux is absolutely irrelevant.
We're left with the middle part: fix timings with subtitle edit.
How exactly one does that?
I know hot to change durations, sync, stuff like that - but they all change the end part of the timings.
How do I do that while preserving the end part?
Which is what I already asked and then explained once, now second time.
I assume you don't mean manually fix all 764 lines, because otherwise I wouldn't have asked here.

[ProWo]

Open your srt in subtitle edit, click on video (menu bar), open video file, open your video, click to add waveform (below), wait until is finished, then double click your first subtitle line (on the left).
On the waveform peaks you can see the subtitle location and duration and in the video frame you can see your first subtile.
On the waveform your can move the subtitle back and forewards and change the duration too.

[queensoft]

OK, so manual fix for 780 lines. Let's not do that.
I can do that in notepad, if I really want to.
Is there another program / option that performs operations while preserving the end time?

[ProWo]

There is no automatism to synchronize the subtitles.
Good luck.

[queensoft]

OK, thanks. Waiting for other opinions.

[october262]

OK, thanks. Waiting for other opinions.

see here - https://stackoverflow.com/questions/57821502/how-to-delay-subtitles-in-ffmpeg
with ffmpeg you can delay the subtitles.

[queensoft]

Yes, ffmpeg can delay subtitles.
Yes, I can do that with absolutely any program that understands subtitles.
If it was that simple, do you think I would have asked here for help?

The "regular" delay is for both start time and end time.
I need the end time to remain the same, to NOT be changed.
Not so much a "delay" as a "change duration" - delay only start time, keep end time the same.
Also, the "delay" is not constant, that's why I need change duration - in percents, keep end time the same.

[ProWo]

... delay only start time, keep end time the same.
Also, the "delay" is not constant, that's why I need change duration - in percents, keep end time the same.

As I said before, you can do that with subtitle edit. However, you have to take a closer look at the program and its possibilities (Synchronization menu).
Three steps, so simple...

[queensoft]

All right, great, thanks.
And because I already know all options from that menu and I have used them many many times, there are 2 possibilities:
1. either I'm a complete id**t right now and I can't find this particular option
2. or this options does not exist.
So, please, please, can you tell me more precisely where is this option?
Thank you.

[ProWo]

It would be better if you used your own brain.
Anyway, here is my solution:

Step 1) note the start time of the last subtitle.

Step 2) determine the desired change of the total length of all
subtitles in percent and apply this change to all subtitles (synchronization, changed speed in percent).

Step 3) calculate the difference of the start time of the last subtitle with the time from step 1) and apply this difference to all subtitles (Synchronization, Adjust all times).

[queensoft]

Not working.
Change speed, from the Synchronization menu, changes the speed of the entire file, progressively.

Example:
Original first line, last line:

1
00:02:02,432 --> 00:02:04,918
ZIUA 1.

761
01:45:03,566 --> 01:45:18,633
inauntrul meu.

Change speed: 90%

1
00:01:50,189 --> 00:01:52,426
ZIUA 1.

761
01:34:33,209 --> 01:34:46,770
inauntrul meu.

First line difference = 12 seconds
Last line difference = 11 minutes.
That will never sync back.

A better option would be Tools > Adjust durations > Percent - this changes each line independently.
The problem is that it subtracts from the end - I need the end time to remain the same.
And if I want to push all lines later, so they all get back to their original END TIME - I cannot do that using absolute values (percent is relative values) - because each line has a different absolute delay.
Example:
Original line duration: 0.720
Change duration 90% = 0.648
Difference: 0.072

Original line duration: 4.410
Change duration 90% = 3.969
Difference: 0.441

Close, but no cigar.

In the end, I'll try this method, seems the closest so far.

[ProWo]

You're doing it wrong.
90% is certainly not the right value.
When should the first subtitle start?

[queensoft]

90% was a test, an example.
For individual lines, 90% is perfectly fine.
Start is not important, end time is important - end time should be unchanged.
But, to answer your question:
Original first line:

1
00:02:02,432 --> 00:02:04,918
ZIUA 1.

Changed first line:
1
00:02:02,932 --> 00:02:04,918
ZIUA 1.

[ProWo]

01:45:03,566 (last sub ST) - 00:02:02,432 (frist sub ST) = 6181,134 seconds.
Your desired starttime for the first subtitle is 500ms later, so the desired new total length is 6181,134-0,500=6180,634.
So you have to insert in step 2 (synchronization, changed speed in percent) a value of 99,99191086942946% (6180,634/6181,134).

[queensoft]

Still not good, probably not even close.
It changes the end way too much.

I took a random line, 148
Original:

148
00:22:02,055 --> 00:22:04,320
Opreste-te aici, bine?

Change speed to 99.99191%, add 0.5 seconds:

148
00:22:02,448 --> 00:22:04,713
Opreste-te aici, bine?

The end is now 0.4 seconds late, it was perfect in the original file.

But, like I said, looks like there is no direct solution / option.
I will test both options and see whihc one is closer.

[ProWo]

Did you do step three?

[queensoft]

Yeah, but I think I did it wrong, let me check again.

[queensoft]

Nope, we're good, difference is 0.5 seconds - last line start time and 0.511 - last line end time.

[ProWo]

Post your srt here, so I'll have a look.

[queensoft]

Here you go.
Also sending email to Subtitle Edit developers

[ProWo]

First Sub ST = 00:00:50,905 When do you want it to start?
Last Sub ST = 01:46:49,282 Is the start time correct?

[queensoft]

First line - start 0.2 seconds later
NOT all lines need to start 0.2 seconds later.
Let's make it like this: change duration of each line to 88%.
Original duration 1.68s - 0.2s = 1.48s = 88%

Last line - start time is correct.

Don't forget, END time of each line must be unchanged (or closest to original END times).
So, pick a random line, process the best way you can think of, compare end time of chosen line.

[ProWo]

Here you go

[queensoft]

Not perfect, but gives me an ideea.
All end times are off, 0.2 - 0.3s late.
Tools > adjust duration again >99.99% (or similar) - it will keep start times the same and bring end times a little closer to original.

OK, great, thanks, I think we're good for now, I have 2-3 things to test more thoroughly.
If I get a reply from the developers, I'll be sure to post it here.

[ProWo]

Not perfect, but gives me an ideea.

You asked for:

1
00:02:02,932
ZIUA 1.

761
01:45:03,566
inauntrul meu.

My srt has these exact times, so what do you mean by not perfect?


[Attachment 73015 - Click to enlarge]

[queensoft]

End times, the end times have to remain exactly the same.
Pick any random line, check end times (not start time, not duration) of both original and your processed file.