An mpv Lua keybinding that makes rewinding seamless across playlist items by switching to playlist-prev when a backward seek would cross time 0 and then seeking from the end of the previous file.

smart_seek_back_playlist.lua

-- smart_seek_back_playlist.lua
-- An mpv Lua keybinding that makes rewinding seamless across playlist items by switching to playlist-prev when a backward seek would cross time 0 and then seeking from the end of the previous file.

-- LEFT seeks back N seconds; if that would cross 0, jump to previous playlist entry
-- and seek from the end by the remaining amount.

local step = 5.0  -- seconds per press (match your LEFT behavior)
local pending_from_end = nil

local function smart_seek_back()
    local pos = mp.get_property_number("time-pos")
    local plpos = mp.get_property_number("playlist-pos", 0)

    -- If time-pos is unknown (streams), just do normal seek.
    if pos == nil then
        mp.commandv("seek", -step, "relative")
        return
    end

    if pos < step and plpos > 0 then
        pending_from_end = step - pos
        -- Go to previous playlist entry (weak = do nothing if already first)
        mp.commandv("playlist-prev", "weak")
    else
        mp.commandv("seek", -step, "relative")
    end
end

mp.register_event("file-loaded", function()
    if pending_from_end ~= nil then
        -- Negative absolute seek counts from end of file; add exact for precision.
        -- Clamp tiny values to avoid corner cases.
        local t = pending_from_end
        if t < 0.05 then t = 0.05 end
        mp.commandv("seek", -t, "absolute+exact")
        pending_from_end = nil
    end
end)

-- Override LEFT. Change "LEFT" to something else if you don’t want to replace it. You may need to comment out your original LEFT binding in input.conf.
mp.add_key_binding("LEFT", "smart_seek_back_playlist", smart_seek_back, { repeatable = true })