ReferenceError: MC is not defined

[LostAndDead]

ReferenceError: MC is not defined
    at Xua (evalmachine.<anonymous>:1:36)
    at evalmachine.<anonymous>:1:165
    at Script.runInContext (node:vm:141:12)
    at Script.runInNewContext (node:vm:146:17)
    at url (c:\Users\jakem\Desktop\Code\MusicBot\Calliope\node_modules\ytdl-core\lib\sig.js:88:22)
    at Object.exports.setDownloadURL (c:\Users\jakem\Desktop\Code\MusicBot\Calliope\node_modules\ytdl-core\lib\sig.js:100:31)
    at <anonymous> (c:\Users\jakem\Desktop\Code\MusicBot\Calliope\node_modules\ytdl-core\lib\sig.js:118:13)
    at Array.forEach (<anonymous>)
    at Object.exports.decipherFormats (c:\Users\jakem\Desktop\Code\MusicBot\Calliope\node_modules\ytdl-core\lib\sig.js:117:11)
    at runMicrotasks (<anonymous>)

The latest version 4.11.2, happens with any song/video requested, I'm unable to trace it to anywhere specific in my code as the error is only within the node modules. Happens every time, and no video is downloaded/streamed. Has been working fine until yesterday with no problems, since yesterday it hasn't worked at all.

[xenorio]

Same here. Just out of the blue, without any changes or even restarts, this shows up.

I would assume something changed on YouTube's side

[matteopolak]

For anyone needing a temporary workaround, you can define MC manually.

At ytdl-core/lib/sig.js:115, replace the decipherScript with the following:

const decipherScript = functions.length ? new vm.Script(`var MC={QO:function(a,b){var c=a[0];a[0]=a[b%a.length];a[b%a.length]=c},"if":function(a){a.reverse()},pn:function(a,b){a.splice(0,b)}};${functions[0]}`) : null;

I've created a fork with this fix, you can replace the dependency temporarily with:

{
  "dependencies": {
    "ytdl-core": "https://github.com/matteopolak/node-ytdl-core.git#d6b56cd67aaa38c22966b98f7b36ad3db4c90192"
  }
}

[xenorio]

@matteopolak Thank you very much, fork works great :)

[kaddyadriano]

@matteopolak @LostAndDead Thank you! I was just starting to have the same issue.

[nextpier]

Thank you @matteopolak ! It's working

[kilianpfr]

@matteopolak ty so much

[richardabear]

Anyone know whats causing this issue? is it an update with youtube? Im not getting the same error but would like to be aware of why that could be happening

[Pnlvfx]

Same

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.