[this_is_eline]

I don't know about 'automatic', but in mpv[1] you have this:

> Ctrl+Shift+Left and Ctrl+Shift+Right

> Adjust subtitle delay so that the next or previous subtitle is displayed now. This is especially useful to sync subtitles to audio.

This works in 9/10 cases. :)

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[1]https://mpv.io/

[riidom]

I think this is what the OP refers to with "fiddle around for ages". I know the problem not with subs, but when audio is off related to the image. And of course the problem is rare enough that I am never "in training", and have to find a remarkable spot first (e.g. door slam shut or a suitable spot in dialogue), then think about going backwards or forwards, guess the amount, etc. etc. :)

[this_is_eline]

If the whole subtitle file is out of sync (e.g. every line is late 2s), one shortcut is all it takes. In that 1/10 case, you do need to 'fiddle around for ages', but given that all other options (e.g. SubtitleEdit[1]) are way more complicated and time consuming, mpv is all I could suggest. For the problem with audio and image being out-of-sync, I have no idea :)

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[1] https://www.nikse.dk/subtitleedit

[OJFord]

For AV sync you can do this in the receiver (and some devices with e.g. Bluetooth support for speakers) because it's not really a problem with the source material (typically anyway) it's just something that does need tuning to the room & hardware.