Change speed of Edpuzzle video

explainer.md

Edpuzzle aggressively reverts the playbackRate of a <video> element, so you can't simply change it to increase the speed. Thus, a more aggressive response is necessary to combat it.

Firstly, we get the <video> element:

video = document.querySelector('video')

Then, we get the setter function for the playbackRate property using Object.getOwnPropertyDescriptor(HTMLMediaElement.prototype, 'playbackRate').set. It is called with the <video> element as this and with speed as the new value. This way, the <video> element is properly notified of the speed change by simulating assigning a value to playBackRate directly (ie using =).

Object.getOwnPropertyDescriptor(HTMLMediaElement.prototype, 'playbackRate').set.call(video, speed)

After that, to prevent Edpuzzle from changing it back, we make playbackRate unwritable, so they can't simply set it:

Object.defineProperty(video, 'playbackRate', { writable: false })

Of course, if we can change the speed this way, so can Edpuzzle, so this might not work in the future.

paste-into-console.js

// Paste the following code in the console (right click > inspect element, then click on the Console tab) on the Edpuzzle page

speed = 2 // Change this to the speed (eg 2 for 2x speed)
video = document.querySelector('video')
Object.getOwnPropertyDescriptor(HTMLMediaElement.prototype, 'playbackRate').set.call(video, speed)
Object.defineProperty(video, 'playbackRate', { writable: false })

I'm getting error Uncaught TypeError: Illegal invocation at <anonymous>:3:81. How to fix this?

@achow0 That might be because video is null. This might be because the Edpuzzle has a YouTube video, so the <video> element is inside an iframe. You should right click > Inspect element on the YouTube video (you may have to right click a few times to show the browser's right click menu), and then try pasting the code.

In my case, I didn't find a <video> element, but instead only an <iframe>. Should I replace video = document.querySelector('video') with video = document.querySelector('iframe') or what?

You will have to select the YouTube frame in the dropdown; this is automatically selected if you right click > Inspect element on the YouTube video itself rather than the outer website

Thank you, that worked. But edpuzzle is now detecting that I'm skipping ahead, even at a 2x speed(Edit: I got it to work at 2x speed, but anything like 4x speed won't work). This will cause the video to be paused very often, and the final result is that it's actually slower than watching it normally. Is there a way to bypass this problem?

Hmm, this video recommends skipping to the end of the video. You can use their method, or use JS; both work:

video = document.querySelector('video')
video.currentTime = video.duration

Then you could open the video in a new tab and watch it at whatever speed you please

Could they not have just defined a setter for the video named playbackRate that will block any attempts to change the playback rate? Or would that throw some error (or be worked around with something like setAttribute)?

Probably; hopefully they don't

Does anyone have an idea if we can also modify how long it says it took to take the edpuzzle on an admin/teacher account page?

anyone got a bookmarklet for this

javascript:(() => { const speed = prompt('Speed', 2), video = document.querySelector('video'); Object.getOwnPropertyDescriptor(HTMLMediaElement.prototype, 'playbackRate').set.call(video, speed); Object.defineProperty(video, 'playbackRate', { writable: false }) })()

Can you help me rewind the video?

Rewind? Does Edpuzzle block seeking previous parts of the video?

this dont work no more

oh well. it's an arms race

have you fixed it i have a 40 minute long video to watch

lazy

Use the method to skip to the end, that one just worked for me on a 24 minute video.

my school blocked inspect element

you alive @SheepTester

that sucks

have you figured out a fix for it because i know nothing about coding

no

I found a fix using a Inspect element bookmarklet and deleting a lot of stuff around the video which unlocks the video so i just skip through refresh the page and answer the questions.

can you make it so a can fast forward throught the video

Yes pls Fix it.