Precache the next entry in your playlist if it is a network source by downloading it to a temp file ahead of time. Change Line 20 to temp directory. It will delete the directory on exit.

ytdl-preload.lua

----------------------
-- #example ytdl_preload.conf
-- # make sure lines do not have trailing whitespace
-- # ytdl_opt has no sanity check and should be formatted exactly how it would appear in yt-dlp CLI, they are split into a key/value pair on whitespace
-- # at least on Windows, do not escape '\' in temp, just us a single one for each divider

-- #temp=R:\ytdltest
-- #ytdl_opt1=-r 50k
-- #ytdl_opt2=-N 5
-- #ytdl_opt#=etc
----------------------
local nextIndex
local caught = true
-- local pop = false
local ytdl = "yt-dlp"
local utils = require 'mp.utils'

local options = require 'mp.options'
local opts = {
    temp = "R:\\ytdl",
    ytdl_opt1 = "",
    ytdl_opt2 = "",
    ytdl_opt3 = "",
    ytdl_opt4 = "",
    ytdl_opt5 = "",
    ytdl_opt6 = "",
    ytdl_opt7 = "",
    ytdl_opt8 = "",
    ytdl_opt9 = "",
}
options.read_options(opts, "ytdl_preload")
local additionalOpts = {}
for k, v in pairs(opts) do
    if k:find("ytdl_opt%d") and v ~= "" then
        additionalOpts[k] = v
        -- print("entry")
        -- print(k .. v)
    end
end
local cachePath = opts.temp

local chapter_list = {}
local json = ""
local filesToDelete = {}

local function exists(file)
    local ok, err, code = os.rename(file, file)
    if not ok then
        if code == 13 then -- Permission denied, but it exists
            return true
        end
    end
    return ok, err
end
local function useNewLoadfile()
    for _, c in pairs(mp.get_property_native("command-list")) do
        if c["name"] == "loadfile" then
            for _, a in pairs(c["args"]) do
                if a["name"] == "index" then
                    return true
                end
            end
        end
    end
end
--from ytdl_hook
local function time_to_secs(time_string)
    local ret
    local a, b, c = time_string:match("(%d+):(%d%d?):(%d%d)")
    if a ~= nil then
        ret = (a * 3600 + b * 60 + c)
    else
        a, b = time_string:match("(%d%d?):(%d%d)")
        if a ~= nil then
            ret = (a * 60 + b)
        end
    end
    return ret
end
local function extract_chapters(data, video_length)
    local ret = {}
    for line in data:gmatch("[^\r\n]+") do
        local time = time_to_secs(line)
        if time and (time < video_length) then
            table.insert(ret, { time = time, title = line })
        end
    end
    table.sort(ret, function(a, b) return a.time < b.time end)
    return ret
end
local function chapters()
    if json.chapters then
        for i = 1, #json.chapters do
            local chapter = json.chapters[i]
            local title = chapter.title or ""
            if title == "" then
                title = string.format('Chapter %02d', i)
            end
            table.insert(chapter_list, { time = chapter.start_time, title = title })
        end
    elseif not (json.description == nil) and not (json.duration == nil) then
        chapter_list = extract_chapters(json.description, json.duration)
    end
end
--end ytdl_hook
local title = ""
local fVideo = ""
local fAudio = ""
local function load_files(dtitle, destination, audio, wait)
    if wait then
        if exists(destination .. ".mka") then
            print("---wait success: found mka---")
            audio = "audio-file=" .. destination .. '.mka,'
        else
            print("---could not find mka after wait, audio may be missing---")
        end
    end
    -- if audio ~= "" then
    --  table.insert(filesToDelete, destination .. ".mka")
    -- end
    -- table.insert(filesToDelete, destination .. ".mkv")
    dtitle = dtitle:gsub("-" .. ("[%w_-]"):rep(11) .. "$", "")
    dtitle = dtitle:gsub("^" .. ("%d"):rep(10) .. "%-", "")
    if useNewLoadfile() then
        mp.commandv("loadfile", destination .. ".mkv", "append", -1,
            audio .. 'force-media-title="' .. dtitle .. '",demuxer-max-back-bytes=1MiB,demuxer-max-bytes=3MiB,ytdl=no')
    else
        mp.commandv("loadfile", destination .. ".mkv", "append",
            audio .. 'force-media-title="' .. dtitle .. '",demuxer-max-back-bytes=1MiB,demuxer-max-bytes=3MiB,ytdl=no')                                                --,sub-file="..destination..".en.vtt") --in case they are not set up to autoload
    end
    mp.commandv("playlist_move", mp.get_property("playlist-count") - 1, nextIndex)
    mp.commandv("playlist_remove", nextIndex + 1)
    caught = true
    title = ""
    -- pop = true
end

local listenID = ""
local function listener(event)
    if not caught and event.prefix == mp.get_script_name() and string.find(event.text, listenID) then
        local destination = string.match(event.text, "%[download%] Destination: (.+).mkv") or
            string.match(event.text, "%[download%] (.+).mkv has already been downloaded")
        -- if destination then print("---"..cachePath) end;
        if destination and string.find(destination, string.gsub(cachePath, '~/', '')) then
            -- print(listenID)
            mp.unregister_event(listener)
            _, title = utils.split_path(destination)
            local audio = ""
            if fAudio == "" then
                load_files(title, destination, audio, false)
            else
                if exists(destination .. ".mka") then
                    audio = "audio-file=" .. destination .. '.mka,'
                    load_files(title, destination, audio, false)
                else
                    print("---expected mka but could not find it, waiting for 2 seconds---")
                    mp.add_timeout(2, function()
                        load_files(title, destination, audio, true)
                    end)
                end
            end
        end
    end
end

--from ytdl_hook
mp.add_hook("on_preloaded", 10, function()
    if string.find(mp.get_property("path"), cachePath) then
        chapters()
        if next(chapter_list) ~= nil then
            mp.set_property_native("chapter-list", chapter_list)
            chapter_list = {}
            json = ""
        end
    end
end)
--end ytdl_hook
function dump(o)
    if type(o) == 'table' then
        local s = '{ '
        for k, v in pairs(o) do
            if type(k) ~= 'number' then k = '"' .. k .. '"' end
            s = s .. '[' .. k .. '] = ' .. dump(v) .. ','
        end
        return s .. '} '
    else
        return tostring(o)
    end
end

local function addOPTS(old)
    for k, v in pairs(additionalOpts) do
        -- print(k)
        if string.find(v, "%s") then
            for l, w in string.gmatch(v, "([-%w]+) (.+)") do
                table.insert(old, l)
                table.insert(old, w)
            end
        else
            table.insert(old, v)
        end
    end
    -- print(dump(old))
    return old
end

local AudioDownloadHandle = {}
local VideoDownloadHandle = {}
local JsonDownloadHandle = {}
local function download_files(id, success, result, error)
    if result.killed_by_us then
        return
    end
    local jfile = cachePath .. "/" .. id .. ".json"

    local jfileIO = io.open(jfile, "w")
    jfileIO:write(result.stdout)
    jfileIO:close()
    json = utils.parse_json(result.stdout)
    -- print(dump(json))
    if json.requested_downloads[1].requested_formats ~= nil then
        local args = { ytdl, "--no-continue", "-q", "-f", fAudio, "--restrict-filenames", "--no-playlist", "--no-part",
            "-o", cachePath .. "/" .. id .. "-%(title)s-%(id)s.mka", "--load-info-json", jfile }
        args = addOPTS(args)
        AudioDownloadHandle = mp.command_native_async({
            name = "subprocess",
            args = args,
            playback_only = false
        }, function()
        end)
    else
        fAudio = ""
        fVideo = fVideo:gsub("bestvideo", "best")
        fVideo = fVideo:gsub("bv", "best")
    end

    local args = { ytdl, "--no-continue", "-f", fVideo .. '/best', "--restrict-filenames", "--no-playlist",
        "--no-part", "-o", cachePath .. "/" .. id .. "-%(title)s-%(id)s.mkv", "--load-info-json", jfile }
    args = addOPTS(args)
    VideoDownloadHandle = mp.command_native_async({
        name = "subprocess",
        args = args,
        playback_only = false
    }, function()
    end)
end

local function DL()
    local index = tonumber(mp.get_property("playlist-pos"))
    if mp.get_property("playlist/" .. index .. "/filename"):find("/videos$") and mp.get_property("playlist/" .. index + 1 .. "/filename"):find("/shorts$") then
        return
    end
    if tonumber(mp.get_property("playlist-pos-1")) > 0 and mp.get_property("playlist-pos-1") ~= mp.get_property("playlist-count") then
        nextIndex = index + 1
        local nextFile = mp.get_property("playlist/" .. nextIndex .. "/filename")
        if nextFile and caught and nextFile:find("://", 0, false) then
            caught = false
            mp.enable_messages("info")
            mp.register_event("log-message", listener)
            local ytFormat = mp.get_property("ytdl-format")
            fVideo = string.match(ytFormat, '(.+)%+.+//?') or 'bestvideo'
            fAudio = string.match(ytFormat, '.+%+(.+)//?') or 'bestaudio'
            -- print("start"..nextFile)
            listenID = tostring(os.time())
            local args = { ytdl, "--dump-single-json", "--no-simulate", "--skip-download",
                "--restrict-filenames",
                "--no-playlist", "--sub-lang", "en", "--write-sub", "--no-part", "-o",
                cachePath .. "/" .. listenID .. "-%(title)s-%(id)s.%(ext)s", nextFile }
            args = addOPTS(args)
            -- print(dump(args))
            table.insert(filesToDelete, listenID)
            JsonDownloadHandle = mp.command_native_async({
                name = "subprocess",
                args = args,
                capture_stdout = true,
                capture_stderr = true,
                playback_only = false
            }, function(...)
                download_files(listenID, ...)
            end)
        end
    end
end

local function clearCache()
    -- print(pop)

    --if pop == true then
    mp.abort_async_command(AudioDownloadHandle)
    mp.abort_async_command(VideoDownloadHandle)
    mp.abort_async_command(JsonDownloadHandle)
    -- for k, v in pairs(filesToDelete) do
    --  print("remove: " .. v)
    --  os.remove(v)
    -- end
    local ftd = io.open(cachePath .. "/temp.files", "a")
    for k, v in pairs(filesToDelete) do
        ftd:write(v .. "\n")
        if package.config:sub(1, 1) ~= '/' then
            os.execute('del /Q /F "' .. cachePath .. "\\" .. v .. '*"')
        else
            os.execute('rm -f ' .. cachePath .. "/" .. v .. "*")
        end
    end
    ftd:close()
    print('clear')
    mp.command("quit")
    --end
end
mp.add_hook("on_unload", 50, function()
    -- mp.abort_async_command(AudioDownloadHandle)
    -- mp.abort_async_command(VideoDownloadHandle)
    mp.abort_async_command(JsonDownloadHandle)
    mp.unregister_event(listener)
    caught = true
    listenID = "resetYtdlPreloadListener"
    -- print(listenID)
end)

local skipInitial
mp.observe_property("playlist-count", "number", function()
    if skipInitial then
        DL()
    else
        skipInitial = true
    end
end)

--from ytdl_hook
local platform_is_windows = (package.config:sub(1, 1) == "\\")
local o = {
    exclude = "",
    try_ytdl_first = false,
    use_manifests = false,
    all_formats = false,
    force_all_formats = true,
    ytdl_path = "",
}
local paths_to_search = { "yt-dlp", "yt-dlp_x86", "youtube-dl" }
--local options = require 'mp.options'
options.read_options(o, "ytdl_hook")

local separator = platform_is_windows and ";" or ":"
if o.ytdl_path:match("[^" .. separator .. "]") then
    paths_to_search = {}
    for path in o.ytdl_path:gmatch("[^" .. separator .. "]+") do
        table.insert(paths_to_search, path)
    end
end

local function exec(args)
    local ret = mp.command_native({
        name = "subprocess",
        args = args,
        capture_stdout = true,
        capture_stderr = true
    })
    return ret.status, ret.stdout, ret, ret.killed_by_us
end

local msg = require 'mp.msg'
local command = {}
for _, path in pairs(paths_to_search) do
    -- search for youtube-dl in mpv's config dir
    local exesuf = platform_is_windows and ".exe" or ""
    local ytdl_cmd = mp.find_config_file(path .. exesuf)
    if ytdl_cmd then
        msg.verbose("Found youtube-dl at: " .. ytdl_cmd)
        ytdl = ytdl_cmd
        break
    else
        msg.verbose("No youtube-dl found with path " .. path .. exesuf .. " in config directories")
        --search in PATH
        command[1] = path
        es, json, result, aborted = exec(command)
        if result.error_string == "init" then
            msg.verbose("youtube-dl with path " .. path .. exesuf .. " not found in PATH or not enough permissions")
        else
            msg.verbose("Found youtube-dl with path " .. path .. exesuf .. " in PATH")
            ytdl = path
            break
        end
    end
end
--end ytdl_hook

mp.register_event("start-file", DL)
mp.register_event("shutdown", clearCache)
local ftd = io.open(cachePath .. "/temp.files", "r")
while ftd ~= nil do
    local line = ftd:read()
    if line == nil or line == "" then
        ftd:close()
        io.open(cachePath .. "/temp.files", "w"):close()
        break
    end
    -- print("DEL::"..line)
    if package.config:sub(1, 1) ~= '/' then
        os.execute('del /Q /F "' .. cachePath .. "\\" .. line .. '*" >nul 2>nul')
    else
        os.execute('rm -f ' .. cachePath .. "/" .. line .. "* &> /dev/null")
    end
end

ok, it should use the youtube-dl in your path and also respects ytdl-format!

Thank you! Now I can see the file being (fully) downloaded. But the file is not actually used, because when starting the next video (which was downloaded) I can see the caching starting from the beginning plus a few seconds waiting time before the video is playing. Also mpv outputs [ytdl_preload] ERROR: Stream #0:0 -> #0:0 (copy) right at the beginning of a video, when preloading also starts.

ok try now. fixed more hardcoded stuff, and tested on ubuntu

It seems to work now. Thanks a ton!

should work with sponsorblock now too

Can you update for yt-dlp which mpv now seeks and uses by default?

Is the "no such file or directory" error expected when playing local files?

rm: cannot remove '/tmp/yt-dlp': No such file or directory

When playing remote files the cache directory and files are created as expected.

updated

• use yt-dlp
• doesn't try to erase if nothing was made

Great. Is it possible to search for both youtube-dl and yt-dlp, accounting for the majority which only has the former installed?

mpv also only prioritizes yt-dlp.

It will know search but the executable has to be in a config folder (i.e. .\portable_config); mpv's directory does not currently count as a config folder. If it doesn't find it there it will try to use yt-dlp from PATH.

Ok, it should retrieve the location the same way mpv does.

Having errors in mpv 0.33 in ubuntu

[ytdl_preload] 
[ytdl_preload] stack traceback:
[ytdl_preload] 	[string "/home/cammera/.config/mpv/scripts/ytdl-preloa..."]:14: in function 'handler'
[ytdl_preload] 	mp.defaults:500: in function 'call_event_handlers'
[ytdl_preload] 	mp.defaults:534: in function 'dispatch_events'
[ytdl_preload] 	mp.defaults:493: in function <mp.defaults:492>
[ytdl_preload] 	[C]: in ?
[ytdl_preload] 	[C]: in ?
[ytdl_preload] Lua error: [string "/home/cammera/.config/mpv/scripts/ytdl-preloa..."]:14: attempt to concatenate upvalue 'title' (a nil value)

It seems to cache the first next video, and then crash after that

@DuendeInexistente
ok should be fixed

Thanks! It's working now

• added chapter insertion
• expanded demuxer bytes from 1mb to 3mb
• removed download delay
• removed Video ID from media title

• removed debug messages
• better: removed Video ID from media title
• improved video format handling

support script-opts?
To change temp directory and download arguments?

@BhaturaGuy could you give an example case where it's useful?
download format is already extracted from your ytdl-format option.

1. Won't have to change cache path each and every time we update the script.

download format is already extracted from your ytdl-format option.

2. True but it doesn't extract ytdl-raw-options, which is somewhat important since I use ytdl-raw-options=format-sort=[vbr,abr] cause default bv+ba sucks.
3. There might be more reasons but I don't see one why not to have script-opts for simply flexibility?

Doesn't appear to currently work with Youtube Music. Neither does yt-dlp 2023.07.06, which reports that 'Youtube Music is not directly supported', but mpv 0.36.0 can nonetheless play entire playlists (i.e. albums; with a delay between track changes of course) at the time.

$ mpv --no-video --audio-client-name=mpv-audio 'https://music.youtube.com/playlist?list=*'

example album

@07416 I think it is working correctly. You are probably still getting a delay with the script because the lookup for the next video is a blocking call. You should still be downloading the next(next) video after that.

I think fixing the delay should be easy, I'll work on it.

@bitingsock I forgot to mention that I'm on Fedora (38) with their limited ffmpeg build (I recently disabled the RPM Fusion repos and moved to mpv and VLC Flatpaks). I could have reproduced in a VM with full logs.

I'll reply if the issue persists with a feature-complete ffmpeg build.

@07416 I don't think ffmpeg limitations would matter if mpv can already play them. try ytdl-preload-test when you get a chance. I changed the blocking call to async.

@BhaturaGuy
please try this new test version, it now includes use of script_opts with custom download args and custom tempdir, better asynchronous downloads, and more robust logic for switching downloads and deleting files

I created ytdl-preload.lua with this script and put it in scripts folder
When I tried to open Youtube video by using mpv, the MPV window is opened in 1s then close automatically
Which wrong step did I do? How to do it in right way

I created ytdl-preload.lua with this script and put it in scripts folder When I tried to open Youtube video by using mpv, the MPV window is opened in 1s then close automatically Which wrong step did I do? How to do it in right way

Same issue with you

Try the new version. I have updated it here. It is the same as my experimental version I mentioned above.

I've updated the script to be compatible with mpv after mpv-player/mpv@c678033

I set ytdl-format in my mpv conf and possible some other ytdl options in future, Can't this pick those options and set it

@Deshdeepak1 It tries to extract the formats from the options on line 260 local ytFormat = mp.get_property("ytdl-format")