MPC-JF ▸ External player launcher for Jellyfin (Windows)

May 15, 2026 · View on GitHub

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▶︎ Features :

  • Support MPC-BE, PotPlayer or MPC-HC (and more ? Try with your own player .exe)
  • Support Jellyfin Web through userscript (Firefox or Chrome-based)
  • Support Jellyfin Media Player (JMP Desktop Windows App) with a DeviceId through JavaScript Injector
  • Alternative version script : add a new yellow Play button to the item pages, external player is only triggered from that icon

Requirements & limitations :

  • Your media folders HDDs/NAS/network drives must be mounted with a letter in Windows (D:\ E:\ ...)
  • Watched states are not synced.

Installation

0. Download MPC-JF.zip

Download latest for Jellyfin 10.11.+ : MPC-JF.zip

1. Place Required Files

  • Before extracting the archive, right-click the downloaded .zip → Properties → check Unblock → Apply. This also unblocks the extracted .ps1 scripts required for execution.
  • Extract and move the MPC-JF folder to : 
    C:\ProgramData\
  • You should end up with: C:\ProgramData\MPC-JF\ (with all files inside).

2. If you don't use MPC-BE and his default path :

  • Edit the file MPCJF.ps1 and replace the path in the last line with your own corresponding path. (MPC-HC or any other player path)
  • E.g. for PotPlayer default path : & "C:\Program Files\DAUM\PotPlayer\PotPlayerMini64.exe" "`"$path`""

4. (Optional) : Installation for Jellyfin Media Player only (JMP Desktop Windows App)

  • Install the JavaScript Injector plugin on your Jellyfin server if it is not already installed. A server restart may be required.
  • Go to: Jellyfin → Admin Dashboard → JS Injector → Add Script
  • Name it MPCJF or whatever, then copy/paste the entire MPC-JF-JSinjector-deviceID.js script.
  • On the PC, go to your corresponding C:\Users\YourUserName\AppData\Local\JellyfinMediaPlayer\logs\
  • Open JellyfinMediaPlayer.log with Notepad.
  • Press Ctrl + F and search for: deviceId: (preferably at the bottom)
  • You should find a line containing deviceId: LongRandomString
  • Copy just that LongRandomString
  • Go back to your script in: Dashboard → JS Injector
  • Paste/Replace: PUT_DEVICE_ID_HERE (into the new script in JS Injector) with your long random string device Id.
  • Check Requires Authentication
  • Check Enabled, then click Save.
Notes : If you do not find deviceId: or the one you copy/paste is not working, close and reopen/reconnect Jellyfin Media Player, then reopen the log file and search again at the bottom.

5. Enable PowerShell Scripts Execution to allow MPCJF.ps1

  • In Windows 11, go to, Settings → Developers → PowerShell → Allow unsigned scripts
  • Or if you can't find it :
    • Search for PowerShell in the Start menu, right-click it, and select Run as Administrator.
    • Type the following command and press Enter:
    Set-ExecutionPolicy RemoteSigned
  • Or 
    Set-ExecutionPolicy RemoteSigned -Force

6. Apply MPC-JF Registry Settings

  • Run MPCJF.reg and confirm changes.
  • You may need to re-run MPCJF.reg after major Media Player Updates.

Optional : Hide the Powerscript window at MPC-JF launch

  • Install-MPCJF-HiddenProtocol.ps1 must be in your default MPC-JF folder.
  • It require VBScript installed (may not be installed by default on all Windows 11 installation)
  • Run the file Install-MPCJF-HiddenProtocol.ps1 (Right click and Run with PowerShell)

Optional : Adjust Full-Screen Settings

  • Fullscreen is On by default
  • Edit "MPCJF.ps1" located in C:\ProgramData\MPC-JF
  • At the end of the script, remove or re-add /fullscreen e.g. "`"$path`""/fullscreen
(not supported by all media players, for PotPlayer you can adjust this in Potplayer's preferences → General → Startup → Startup → Window Size)

7. Done !

  • Restart your web browser and/or refresh Jellyfin Web UI, test if it works already. If not, see Workaround below.

Workaround : If the Media Player starts but fail to launch the media

  • Your NAS/network drives must be mount with a letter like D:\ E:\ ... in Windows.
  • Edit "MPCJF.ps1" located in C:\ProgramData\MPC-JF
    • At the end of the file, just below : # YOUR NAS CONFIG, IF NEEDED, ADD YOUR OWN WORKAROUND JUST BELOW
    • For each drive, add this line : $path = $path -replace "\\share\\SHAREFOLDER\\", "D:"
    • In this, change "\\share\\SHAREFOLDER\\" It should be the part of the path that appear in your NAS (and maybe in your library path in Jellyfin server too), but not appearing in the Windows explorer path of your movies.
    • Add double backslash \\ instead of single backslash \ in your own path, they are essential.
    • Replace "D:" with the corresponding drive letter in Windows.
    • For exemple $path = $path -replace "\\share\\MEDIA\\", "D:" That works for everything located in my NAS mounted as the D: drive in Windows, so D:\FILMS, D:\SERIES, D:\FILMS\folder1\Movie1.mkv etc.
    • If you have other drives, do the same for them by adding lines below.
    • No need to do add lines for every library folder, just one line for each different drive should be enough.

TIPS :

  • Re-run MPCJF.reg (& Install-MPCJF-HiddenProtocol.ps1) after a new Media Player/MPC/Potplayer update
  • You will have to checkmark the media as watched in Jellyfin yourself...
  • MPC-HC is not the best anymore to use with MadVR, try Potplayer, it's highly customizable and support nearly all renderer including madVR and D3D11 with RTX video.
  • To Resume watching the last media, set your Player settings to resume the last file automatically at openning → Potplayer's preferences → General → Startup → Check Play the last played item (and open the player instead of jellyfin to resume).
  • If you change your server adress : modify the installed MPCJF userscript : Browser settings → Extensions → Violentmonkey → Options → Go to Installed Scripts → MPC-JF </>
  • If Jellyfin removed or changed you JMP deviceId : re-do step 4 deviceId: part.
  • If MPC takes time to launch the media, it's because HDDs are in standby and MPC is waiting for them to respond. I have made a tiny watcher that wake up my NAS HDDs at JF Home screen for faster first play here : jellyfin-nas-hdd-spinup
  • To uninstall Install-MPCJF-HiddenProtocol.ps1 : run in Powershell : 
    Remove-Item -Recurse -Force "HKCU:\Software\Classes\MPCJF" -ErrorAction SilentlyContinue
Remove-Item -Recurse -Force (Join-Path $env:LOCALAPPDATA "MPCJF") -ErrorAction SilentlyContinue
  • If you use the Firefox extension Dark Reader , it breaks Jellyfin pictures loading in browsers, desactivate it only for jellyfin : Go into Dark Reader settings while you have the Jellyfin page open (firefox menu bar), click to Jellyfin URL.
  • Here is my guide with many quality-of-life improvements for using Jellyfin (lots of tips and tricks, auto-start-stop server, fullscreen UI, shortcut links to media folders, etc.) : PPFJ

Files in C:\ProgramData\MPC-JF

  • MPCJF.ps1 : Do not delete. Main Script.
  • MPCJF.reg : Do not delete. You may need to run it again if the script don't run anymore, maybe after some PotPlayer/MPC updates.
  • Install-MPCJF-HiddenProtocol.ps1 : One time run to hide the Powershell window at Player launch. You may need to run it again after some PotPlayer/MPC updates.
  • MPCJF.user.js : Main browser script, it's in ViolentMonkey in your browser. Use this one if an auto-update of the script have broken things for your version.
  • MPC-JF-JSinjector-deviceID.js : Jellyfin Media Player (Desktop App) JS Injector script.

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