[UX] Seek length should respect the playback speed value

[oficsu]

Expected behavior of the wanted feature

Let's start off with a rough example. When you're watching a game speedrun, each frame is important and you would sometimes lower the playback speed to 0.05 or 0.01 values. Then, if you want to rewatch the previous moment, seeking back 5 seconds (the default seek value) will scale to 100 (or 500) seconds — an immense amount of real/effective watch time. Even shift+arrow won't give you 5 seconds of real duration then. Of course, it's easy to imagine examples also for faster playback — x1.5, x2, x3

Why not add more seek shortcuts with different values? It won't work, since all users have different preferences and many of them watch different videos at different speeds. Neither you nor users can keep adding new seek shortcuts for 0.5/0.25/10/20/etc seconds or choosing the right shortcut during video watching

Why add this directly to mpv and not to a plugin? Seeking by effective watch time feels natural. Seeking by 500 seconds does not. Even more than that, I propose not only adding a new playback-speed-aware seek command respecting playback speed, but also changing default seek keybindings to this option, as it fixes UX

Maybe it would be even consistent with the default OSC that shows effective time in "time left" section, but still inconsistent with "time elapsed" (why they're different?)

[hooke007]

Never heard about such cases.
But Just add anything you like in your conf.

[oficsu]

@hooke007,

Never heard about such cases

So here I am to tell you about us, the users — and about our cases. Yes, I personally watch videos in a very wide range of playback speeds, from x0.01 up to x4, depending on its content

But Just add anything you like in your conf

If you're proposing to add more shortcuts with different seek values for different cases, it won't work — and I've already said why. There would be just too many different shortcuts for such a wide range

If you're proposing to write a lua script that would implement the feature I'm requesting here (seeking proportional to the current speed), I really can do that for myself. But as I explained, the requested behavior is a much more natural UX than the current one, so other users (like me) could benefit from implementing it directly in mpv. The rest of the users (who always watch in x1) won't be affected, no one gets hurt

And again. Even for such regular values as x0.5 or x2, it's a noticeable difference: if a user seeks 5 seconds back, they would, from basic intuition, expect to see the same content they saw 5 seconds ago — not 10 seconds (in x0.5), and not 2.5 seconds ago (in x2)

[guidocella]

Personally I like the idea.