Fastest way to adjust subtitle fps and delay for any scenario

[forthrin]

What is the intended workflow of —sub-fps and —sub-delay options, and how well does this cover all use cases?

If the framerate matches, it's usually relatively easy, but if both delay (eg. segment added/removed in the beginning) and framerate factor (may be quite arbitrary at times) are off, you have to fumble a lot to get the two values just right.

Save speech recognition, the following steps seem necessary to find the perfect adjustments for any situation:

1. Play the video and write down observed time codes of the first and last spoken sentence.
2. Use a script to calculate an offset and “stretch” value* and adjust all timecodes accordingly.
3. Play the video again, and repeat step two with slight adjustments until the timing is perfect.

*) (observed_last - observed_first) / (file_last - file_first)

Is the current implementation in mpv optimal or even useful? Does this even belong in mpv? What is the best approach?

[forthrin]

@kasper93: Great obsoleting stale reports, but reopen this one and move to Discussions?