Yt6 -- Snarl's YouTube Video Player (bookmarklet)

Latest version: 2026-07-22-20:20

Features

1. Restrict on-site advertisement -- suppress endscreen cards, auto-skip or just auto-mute video ads (in case some may be interesting to you),
2. Resize, zoom, rotate and move around video picture arbitrarily,
3. Pick your favoured and supported video/audio codec and resolution for playback,
4. Select a desired media segment to loop -- custom loop segments become active once the starting and ending time input fields disappear,
5. Change playback rate ("speed" or tempo) from 0 up to 16x,
6. Replace soundtrack with any external audio (or video) file across the net
Works only if you select a video-only format of the youtube video, and play it back with the progressive download method,
7. Boost audio level to fix very silent or very loud sound (same limitation as above),
8. Download the video/audio content -- YouTube's throttling mechanism diminishes transfer rate. To speed it up, right-click on a download link, "Open in new tab", and start the download process from there by right-clicking the media & "Save as...",
9. Save video commercials as well, usually accessible through the alternative links,
10. "Shorts" videos media extraction (at least on desktop),
11. Download subtitles/closed captions (CC)
    On bookmarklet line, you can edit the value of "add_subs" after the equal sign and between apostrophes (a comma separated list of ISO 639-1 languge codes, such as 'en, de, fr, es, ja'...) to add Google-Translated tracks of your choice,
12. facilitate background play on mobile while sleep mode is on (varying success, depends on the device),
13. Bypass age verification -- Google patched the loophole late '24, the only option to watch videos like these is to use the credentials of an eligible YouTube account (i.e. log in)
    Examples: Tunnel Vision (signatures encrypted), Cobra (signatures unencrypted)
    
14. Make videos available on mobile which are otherwise restricted to desktop only; not working, patched as well
    Examples: Basic Instinct (MON) (STUDIO CANAL), The Relic - Trailer
    
Change between YouTube layouts by setting the cookie on exit
YouTube stopped honoring the setting in July 2020 and shut down its classic layout for good early December. I wrote a userscript that partially restores it though. See the YouTube Classic layout section for details.

- leaving the current YT subdomain,
- typing URLs directly to the address bar instead of following links,
- or even just navigating between two points in your browsing history where a full page refresh has already taken place

Bookmarklet Setup

1. Right click (on mobile, hold your finger) on the Yt6 link above, and "Copy link address".
If you have no such option, the code is written in plain text below, select and copy it manually.
2. Bookmark any web page (this one for example)
3. Edit the created bookmark's Properties / Location:
delete its URL-address entirely and paste this snippet of javascript code in its place. (Optionally, you can give it a name of your choice too.)
4. Save the changes if there is a Save button!

BOOKMARKLET CODE IN PLAIN TEXT (copy)

javascript:(function(){var v='c5d0c53ccd123e645c610150725f75061abaeeac/yt6.js',y='youtube.com/',w=window,d=w.document,h=d.location.href,yt6=w.yt6||{},yt6d=w.yt6d||{},t=w.trustedTypes,n;if(yt6d&&yt6d.loaded>=4)return void 0;if(h.split(y+'watch')[1]||h.split(y+'embed')[1]||h.split(y+'playlist')[1]||h.split(y+'shorts')[1]||h.split('/base.j')[1]=='s'){var id='snarls_player',e='script',q,u=function(s){if(typeof s=='string')return s};try{t.createPolicy('default',{createHTML:u,createScriptURL:u,createScript:u,})}catch(f){};if(yt6)yt6.loaded=0;function s(x){x=x||id;return d.getElementById(x)};function gt(x,f){return f.getElementsByTagName(x)};function gn(){n=gt('head',d)[0];n=(n)?gt('link',n)[0]:'';if(!(n&&n.nonce)){n=gt('script',d);var i;for(i=0;i<n.length;i++)if(n[i]&&n[i].nonce){n=n[i].nonce;break};if(typeof n!='string')n=''}else n=n.nonce;return n};function c(e){e=d.createElement(e);e.nonce=gn();return e};function a(q){s().appendChild(q);gt('script',s())[0].setAttribute('nonce',gn());s().add_subs='en,hu,de';s().version='2026-07-22-20:20';if(yt6d)yt6d.src=q.src};function r(){if(s()){var x;try{x=s().querySelector('#'+id)}catch(e){x=s().firstChild};if(x)s().removeChild(x)}};function b(){var i,j,o,x;o=['rawcdn.githack','js','cdn.rawgit'];for(j,x,i=o.length;i;j=Math.floor(Math.random()*i),x=o[--i],o[i]=o[j],o[j]=x);q=c('div');q.id=id;if(q!=s())d.body.appendChild(q);var src='https://'+o[0]+'.com/snarly/yt6/'+v,src0='https://cdn.jsdelivr.net/gh/snarly/yt6@'+v; function oc(ox,oy,sr){h=(oy!='js')?sr.replace(ox,oy):src0;if(yt6d)yt6d.src=h;return h};q=c(e);q.id=id;q.src=(o[0]!='js')?src:src0;if(yt6d)yt6d.src=q.src; q.onerror=function(){q=c(e);q.id=id;q.src=oc(o[0],o[1],src);q.onerror=function(){q=c(e);q.id=id;q.src=oc(o[0],o[2],src);q.onerror=function(){q=c(e);q.id=id;q.src=oc(o[0],o[3],src);q.onerror=function(){q=c(e);q.id=id;q.src=src.replace('https','http')};a(q);r();};a(q);r();};a(q);r();};try{a(q);}catch(f){a(q)};};function g(){try{deldiv()}catch(f){r()};b()};if(!s()){b()};setTimeout(function(){var t=w.yt6;if(t)t.loaded=t.loaded||window['status'];if(!t||(t&&(!t.body||(t.loaded<3))))g()},3000);}else{void 0};})()/*2026-07-22-20:20*/

Userscript Setup

Greasemonkey (for Firefox),
Tampermonkey (for Firefox, Chrome, Edge and Opera)
Violentmonkey (for Firefox, Chrome and Edge) or
Wildmonkey (for Firefox, Chrome and Edge)

(Wildmonkey needs the "// @match" lines copied to its URL input field minus the "// @match" part)

USERSCRIPT CODE IN PLAIN TEXT (copy)

// ==UserScript==
// @name         Yt6 -- Snarl's YouTube Video Player (userscript)
// @namespace    yt6
// @version      2026-07-22-20:20
// @author       Snarl
// @description  Auto-Load Yt6 script as soon as possible
// @match        https://*.youtube.com/watch*
// @match        https://*.youtube.com/embed/*
// @match        http://*.youtube.com/watch*
// @match        http://*.youtube.com/embed/*
// @grant        none
// @run-at       document-end
// @icon         https://yt3.ggpht.com/-afBnHVG_R6E/AAAAAAAAAAI/AAAAAAAAAAA/LtE5kbPkZvE/s27-c-k-no-mo-rj-c0xffffff/photo.jpg
// ==/UserScript==


(function(){

  window['yt6'] = {}; window['yt6d'] = {};

  var idle_time = 1500 // wait some time before running the bookmarklet part, you may need those extra seconds especially if you're logged in to YouTube

  var onComplete = function(){ //javascript:
	(function(){var v='c5d0c53ccd123e645c610150725f75061abaeeac/yt6.js',y='youtube.com/',w=window,d=w.document,h=d.location.href,yt6=w.yt6||{},yt6d=w.yt6d||{},t=w.trustedTypes,n;if(yt6d&&yt6d.loaded>=4)return void 0;if(h.split(y+'watch')[1]||h.split(y+'embed')[1]||h.split(y+'playlist')[1]||h.split(y+'shorts')[1]||h.split('/base.j')[1]=='s'){var id='snarls_player',e='script',q,u=function(s){if(typeof s=='string')return s};try{t.createPolicy('default',{createHTML:u,createScriptURL:u,createScript:u,})}catch(f){};if(yt6)yt6.loaded=0;function s(x){x=x||id;return d.getElementById(x)};function gt(x,f){return f.getElementsByTagName(x)};function gn(){n=gt('head',d)[0];n=(n)?gt('link',n)[0]:'';if(!(n&&n.nonce)){n=gt('script',d);var i;for(i=0;i<n.length;i++)if(n[i]&&n[i].nonce){n=n[i].nonce;break};if(typeof n!='string')n=''}else n=n.nonce;return n};function c(e){e=d.createElement(e);e.nonce=gn();return e};function a(q){s().appendChild(q);gt('script',s())[0].setAttribute('nonce',gn());s().add_subs='en,hu,de';s().version='2026-07-22-20:20';if(yt6d)yt6d.src=q.src};function r(){if(s()){var x;try{x=s().querySelector('#'+id)}catch(e){x=s().firstChild};if(x)s().removeChild(x)}};function b(){var i,j,o,x;o=['rawcdn.githack','js','cdn.rawgit'];for(j,x,i=o.length;i;j=Math.floor(Math.random()*i),x=o[--i],o[i]=o[j],o[j]=x);q=c('div');q.id=id;if(q!=s())d.body.appendChild(q);var src='https://'+o[0]+'.com/snarly/yt6/'+v,src0='https://cdn.jsdelivr.net/gh/snarly/yt6@'+v;
    function oc(ox,oy,sr){h=(oy!='js')?sr.replace(ox,oy):src0;if(yt6d)yt6d.src=h;return h};q=c(e);q.id=id;q.src=(o[0]!='js')?src:src0;if(yt6d)yt6d.src=q.src;q.onerror=function(){q=c(e);q.id=id;q.src=oc(o[0],o[1],src);q.onerror=function(){q=c(e);q.id=id;q.src=oc(o[0],o[2],src);q.onerror=function(){q=c(e);q.id=id;q.src=oc(o[0],o[3],src);q.onerror=function(){q=c(e);q.id=id;q.src=src.replace('https','http')};a(q);r();};a(q);r();};a(q);r();};try{a(q);}catch(f){a(q)};};function g(){try{deldiv()}catch(f){r()};b()};if(!s()){b()};setTimeout(function(){var t=w.yt6;if(t)t.loaded=t.loaded||window['status'];if(!t||(t&&(!t.body||(t.loaded<3))))g()},3000);}else{void 0};})()
    ////2026-07-22-20:20//
  }

  var check = function(){ // conditions to meet before loading
    var x = window['performance']
    if (x && x.timing && x.timing.loadEventEnd > 0 && x.timing.loadEventEnd >= x.timing.domComplete && window['yt6'] && !window['yt6'].body) //setTimeout(function(){ window['yt6'].body = 1 }, 1000); if (window['yt6'].body === 1)
      return true
  }

  if (check()) {
      setTimeout(function(){ onComplete() }, idle_time)
      return
  }

  var delay = 1000, timeout = 30000 // after timeout loading the Yt6 script will be attempted even if the video page still has not finished constructing itself

  var timeoutPointer
  var intervalPointer = setInterval(function () {
      if (!check()) return

      clearInterval(intervalPointer)
      if (timeoutPointer) clearTimeout(timeoutPointer)
      if (typeof onComplete == 'function') setTimeout(function(){ onComplete() }, idle_time)
  },delay)

  if (timeout) timeoutPointer=setTimeout(function () {
      clearInterval(intervalPointer)
  },timeout)

})()

If the program launched via userscript appears dysfunctional in Desktop view, edit the userscript code through the manager's Dashboard* and try to set the idle_time variable to a higher value (the number is in milliseconds).

Prerequisites

If you use addons like NoScript (recommended for advanced users), make sure to

Whitelist / Trust these domains permanently:

Desktop browser addons

1. Simple Modify Headers
   • for Mozilla Firefox and its derivatives
   • Chrome Web Store*
     
   • Microsoft Edge Store
   
   Use the "Configure" option of the addon-icon and edit the data fields with values of one of the following combinations:
   
   

   Url Patterns:	https://*.youtube.com/*
   Action	Modify
   Header Field Name	Content-Security-Policy
   Header Field Value	script-src 'unsafe-eval' 'self' 'unsafe-inline' 'none' https://www.google.com https://apis.google.com https://ssl.gstatic.com https://www.gstatic.com https://www.googletagmanager.com https://www.google-analytics.com https://*.youtube.com https://*.google.com https://*.gstatic.com https://youtube.com https://www.youtube.com https://google.com https://*.doubleclick.net https://*.googleapis.com https://www.googleadservices.com https://tpc.googlesyndication.com https://www.youtubekids.com https://www.youtube-nocookie.com https://www.youtubeeducation.com https://www-onepick-opensocial.googleusercontent.com https://cdn.jsdelivr.net https://rawcdn.githack.com https://cdn.rawgit.com
   Comment	allow jsdelivr githack rawgit
   Apply on	Response

   ... or ...
   
   

   Url Patterns:	https://*.youtube.com/*
   Action	Delete
   Header Field Name	Content-Security-Policy
   Header Field Value
   Comment	disable csp on youtube only
   Apply on	Response

   
   Click "Save"... "Start" / "Stop" the addon as needed, and reload the YT page.
   
   
2. Disable-CSP -- Simple ON / OFF switch, handles all websites at once (in our case it's enough to toggle the HTTP CSP)
• Chrome Web Store*
  
• Microsoft Edge Store


3. Allow-CSP -- Simple ON / OFF switch, handles all websites at once
• Chrome Web Store*
  
• Microsoft Edge Store

Mobile browser addons

1. Simple Modify Headers Extended for Firefox Mobile
To set it up, open a page on YT, and under browser Settings / Extensions, tap the name of this extension -- instead of the gear sign next to it -- then tap Configure and select the predefined "disable CSP" Rule Set for a similar effect to having Disable-CSP or Allow-CSP turned on on a Chromium-based browser.
On desktop, you can restrict this add-on to activate on YouTube only: use the "+Add" button next to the Rule Set field, give the new Rule Set a telling name like youtube, and set the same values shown on one of the two tables for Simple-Modify-Headers above, with the exception of "Url Pattern:" which record here is renamed to "When URL contains:" and its value must be set to .youtube.com/


2. Violentmonkey and Tampermonkey in conjunction -- the savior to Edge Mobile
   You have to install and allow them to "Run in InPrivate" through the browser's Extensions / Manage extensions menupoint. (Only the few addons listed there are compatible with recent builds of Edge Mobile, the versions found in the web stores are not.) There is a chance Tampermonkey may work on its own, Violentmonkey needs assistance from Tampermonkey.
   • On Tampermonkey's Dashboard / Settings, "Config mode" needs to be set to "Advanced" -- this will make the Security section appear on the same page
   • Look for the line
     "Modify existing security policy (CSP) headers:" and select "Remove entirely (possibly unsecure)"
   • Tap "Save" at the end of the Security section
   • You can add the Yt6 userscript to either Violentmonkey or Tampermonkey -- delete the auto-generated default script-template, select, copy and paste the userscript code above, and save the changes. This must be completed in a regular browser window, and private windows with YT content need to be closed and reopened after these edits were made.

Other useful addons

How to use

1. Tap the browser's address bar first (NOT the YouTube search bar!)
this should select / highlight the whole URL-address of the current YouTube video page.
(If it does not, hold your finger on the address bar a bit longer till the system offers the option to "Select all".)
2. Once you start typing its name ("Yt6" or whatever you named it),
the browser should suggest the bookmarklet as an available option.
(If it does not, head to the browser Settings, and turn on Search Suggestions which shall include bookmark names, and try again. Unfortunately, not all browsers support this.)
3. Tapping on the correct entry shall initiate the call.
   

0 -- is for debugging purposes only,
1 -- switch back to the standard layout,
2 -- to load a window/screen-sized video embed frame,
3 -- the YouTube Music subdomain version (available for musical content only).

Issues with usage on Mobile

(Attempted) Background play on Mobile

• the 160k WebM Opus (251) audio or
• the 128k DASH AAC (140) audio format.

Supported browsers

Good

1. Firefox
   the uBlock Origin add-on is working again
2. Firefox Nightly
   works reasonably well even without uBlock Origin
3. Waterfox
   no support for bookmarklets, opt for the userscript solution
   
   
   

   Bad

   Chromium-based browsers have been actively preventing background play on mobile for some time now. You may get away with a couple of videos in a row on older versions of the Android OS.
   
   
4. Kiwi
5. Edge
   
   

   Ugly

   Unsupported mostly due to YouTube's new Content Security Policy (CSP)
   
   
6. Brave
7. Vivaldi
8. Google Chrome
9. Ecosia
10. Mull*
11. DuckDuckGo
12. Chromium*
13. Bromite*
14. Yandex
15. Opera
16. Firefox Focus, Samsung, Qwant, Mint ...

Legacy browsers

https://www.youtube.com/
watch?v=mfTpjrzas5E
&list=PLNxOe-buLm6cz8UQ-hyG1nm3RTNBUBv3K

https://www.youtube.com/
embed/mfTpjrzas5E
?list=PLNxOe-buLm6cz8UQ-hyG1nm3RTNBUBv3K

https://www.youtube.com/embed/d020hcWA_Wg?list=PLNxOe-buLm6cz8UQ-hyG1nm3RTNBUBv3K

https://www.youtube.com/embed/nVhNCTH8pDs?list=PL0SqtI95X6o3xmzWnIwD_BgVQyjXkuT_u

Stream capturing

(YouTube may replace the stream-only URLs with regular ones after the video reaches a certain level of popularity.)

./yt_streamcat target_file "stream_base_URL" start end "2nd_stream_URL"

./ means the program file is located in the current directory (in Windows, .\ would mean the same thing)
yt_streamcat
is the script file we run as our command
target_file (mandatory)
is a user-specified file the media segments are going to be written into -- must not exist yet, if it does, the script will abort to prevent an accidental overwrite
"stream_base_URL" (mandatory)
is a YT stream source URL originating from one of the two possible types of videos mentioned above, extracted by the yt6 main program. Must be enclosed in quotation marks to prevent bash from misinterpreting each URL-parameter (after each "&" sign) as yet another command to run in the background.
start (optional)
is the number of the segment the media should begin download from. For live streams, you should give this a value somewhere between the first and last available "sq" (segment query?) parameter values which you can read on the DASH and HLS Manifest URL lines. If you go over that range, the download will start with the most recent live segment. If you go below it, the download will stall.
end (optional)
is the number of the ending segment, or if it's less than the previous number, it will be interpreted as the number of segments to download
"2nd_stream_URL" (optional)
to save another track parallel to the first one (an audio stream, maybe?). Must be between quotes as well. (You must specify the previous two options in order to be able to specify this fifth one.)

#!/bin/bash

./yt_streamcat v \
"https://[...]googlevideo.com/videoplayback?[...]" \
100 \
150 \
"https://[...]googlevideo.com/videoplayback?[...]"
	

Remuxing commandline examples:

mencoder v.mp4 -ovc copy -o v2.mp4

mencoder v.webm -ovc copy -mc 0 -noskip -fps 30 -ofps 36 -o v2.webm

mencoder v2.webm -ovc copy -ss 4 -o v3.webm

ffmpeg -i v3.webm -i vA.aac -c:v copy -c:a copy v.mkv

__

John Dyer - Mediaelementplayer - http://mediaelementjs.com/
Christian Heilmann - Transformvideo - http://github.com/codepo8/rotatezoomHTML5video
Steven Penny - Youtube download bookmarklet - (closed account)

__

Important Notes

1. On videos with strong copyright protection, it is often the case that YouTube sends deliberately wrong signature decryption keys on the first try. I did not implement a fully automatic update of video signatures because of the high risk of infinite loop on repeated failure. You MUST switch over to the alternative player to manually initiate playback on multiple formats till enough errors occur for the updating procedure to fire. The video can be downloaded as soon as it becomes playable on the alt-player. The appearing blue gauge on its time rail shows that the video data has arrived and is buffering.




2. The alternative player of Yt6 uses the Progressive Download method to access video & audio instead of the Adaptive Streaming YouTube's own player had as the default since late 2013.
   
   Both have their pros and cons. With the former, media is getting piled up in the browser's cache during playback, which means there must be enough free space for storage either in the system RAM or on the disk. While in the case of streaming, you only have tiny slices of the media buffered at all times, which in turn requires higher CPU-power and constantly fast network speeds.
   Consequently, for live streams or Ultra-HD videos it is recommended to switch over to YouTube's native player, as it is much better suited for those.
   
   To make sure your browser chooses memory over the much slower and/or fragile Hard Disk / Solid-state drive, use the program in an Incognito / In-private browser window or tab.



Occasionally, some age-restricted videos may get the same subdomain for their source location as known YouTube video commercials which have already been registered with adblockers such as uBlock Origin or Brave Browser's ad-shield, and as a result, their download links will be made inaccessible by these adblockers as well. Except if

1. you are logged in to an eligible YouTube account
2. don't use ad-blockers at all
3. or set up exceptions in the ad-blocker's settings
For example, on uBlock Origin's control panel, the explicit greenlighting of the domains

youtube.com -- for the player data and
googlevideo.com -- to access the media links

will do the trick, although this way you may end up getting some video ads too.
(You first need to activate the Advanced User mode in uBlock Origin's settings menu to be able to do this. Tutorial: https://www.youtube.com/watch?v=SIYcI2tEqo8)