支持通过快捷键，装载滤镜型次字幕的mpv脚本

vf_sub.lua

--[[
SOURCE_ https://github.com/mpv-player/mpv/blob/master/TOOLS/lua/autoload.lua
COMMIT_ 3ba446d0b065f867ca262a2e05e4e8d24c7c0783
SOURCE_ https://github.com/rossy/mpv-open-file-dialog/blob/master/open-file-dialog.lua
COMMIT_ 04fe818fc703d8c5dcc3a6aabe1caeed8286bdbb
文档_ https://github.com/hooke007/MPV_lazy/discussions/106

示例：在 input.conf 中另起写入下列内容
 Ctrl+Alt+1 script-binding vf_sub/append_vfSub   # 装载次字幕（滤镜型）
 Ctrl+Alt+2 script-binding vf_sub/append_vfSub_2 # 装载文件中的第2个字幕（滤镜型）
 Ctrl+Alt+3 script-binding vf_sub/append_vfSub_3 # 装载文件中的第3个字幕（滤镜型）
 Ctrl+Alt+9 script-binding vf_sub/append_vfSub_9 # 装载文件中的第9个字幕（滤镜型）
 E          script-binding vf_sub/toggle_vfSub   # 隐藏/显示 当前的次字幕（滤镜型）
 CTRL+e     script-binding vf_sub/remove_vfSub   # 移除次字幕（滤镜型）
]]

local msg = require "mp.msg"
local options = require "mp.options"
local utils = require "mp.utils"

function append_vfSub(index)
	local was_ontop = mp.get_property_native("ontop")
	if was_ontop then mp.set_property_native("ontop", false) end
	local res = utils.subprocess({
		args = { 'powershell', '-NoProfile', '-Command', [[& {
			Trap {
				Write-Error -ErrorRecord $_
				Exit 1
			}
			Add-Type -AssemblyName PresentationFramework
			$u8 = [System.Text.Encoding]::UTF8
			$out = [Console]::OpenStandardOutput()
			$ofd = New-Object -TypeName Microsoft.Win32.OpenFileDialog
			$ofd.Multiselect = $false
			If ($ofd.ShowDialog() -eq $true) {
				ForEach ($filename in $ofd.FileNames) {
					$u8filename = $u8.GetBytes("$filename")
					$out.Write($u8filename, 0, $u8filename.Length)
				}
			}
		}]] },
		cancellable = false,
	})
	if was_ontop then mp.set_property_native("ontop", true) end
	if (res.status ~= 0) then return end
	for filename in string.gmatch(res.stdout, '[^\n]+') do
		local vfSub
		if index then
			vfSub = "vf append ``@LUA-load_plus:subtitles=filename=\"" .. res.stdout .. "\":stream_index=" .. index .. "``"
		else
			vfSub = "vf append ``@LUA-load_plus:subtitles=filename=\"" .. res.stdout .. "\"``"
		end
		mp.command(vfSub)
	end
end

function filter_state(label, key, value)
	local filters = mp.get_property_native("vf")
	for _, filter in pairs(filters) do
		if filter["label"] == label and (not key or key and filter[key] == value) then
			return true
		end
	end
	return false
end

function toggle_vfSub()
	local vfSub = "vf toggle @LUA-load_plus"
	if filter_state("LUA-load_plus") then mp.command(vfSub) end
end

function remove_vfSub()
	local vfSub = "vf remove @LUA-load_plus"
	if filter_state("LUA-load_plus") then mp.command(vfSub) end
end

mp.register_event("end-file", remove_vfSub)
mp.add_key_binding(nil, "append_vfSub", append_vfSub)
mp.add_key_binding(nil, "append_vfSub_2", function () append_vfSub(2) end)
mp.add_key_binding(nil, "append_vfSub_3", function () append_vfSub(3) end)
mp.add_key_binding(nil, "append_vfSub_9", function () append_vfSub(9) end)
mp.add_key_binding(nil, "toggle_vfSub", toggle_vfSub)
mp.add_key_binding(nil, "remove_vfSub", remove_vfSub)