I use this constantly when I'm watching tutorials and how-tos. It makes picking up the info you need so much faster.

I also recently discovered that the Crocodile Hunter at 1/2 speed is freaking hilarious. e.g.,

https://www.youtube.com/watch?v=QLIMgXv89VU&feature=youtu.be...

and when you need something between 1.25 and 1.5 available from UI, you can always do:

  document.getElementsByTagName('video')[0].playbackRate = 1.35

Nice hack. I always found 1.25 to be "too slow" for watching something but 1.5 to be way too fast and annoying.

I've as a habit downloaded videos manually just to speed them up. When watching a video for it's information, I can usually, and not uncomfortably listen to it at around 1.7-1.8 depending on speaker. It takes a little getting used to though. I'll say that.

It may simply be me, but in Firefox, I don't have the option to change speeds. *update: It looks like they haven't rolled out the change everywhere. I had to change it to HTML5. It still defaults to flash apparently.

I believe that the YouTube HTML5 video rollout depends on parts of the Media Source Extensions, which are only available in Firefox starting in beta.

Media Source Extensions in Firefox is cutting-edge stuff; you can follow along in https://bugzilla.mozilla.org/show_bug.cgi?id=778617.

The article states what browsers default to HTML5: "YouTube uses HTML5 <video> by default in Chrome, IE 11, Safari 8 and in beta versions of Firefox."

The Crocodile Hunter at 1/2 speed is amazing. I would love it if there was a listing of all videos that are hilarious at 1/2 speed.

NDT sounds completely smashed when at half speed -

https://www.youtube.com/watch?v=danYFxGnFxQ

DHH's Ruby on Rails demo is pretty hilarious at half speed: http://youtu.be/Gzj723LkRJY

I recommend watching Handmade Heroes at 0.5x. Its a good series but if you put it on 0.5x it is quite amusing. :)

It is worth pointing out that Chrome and IE are miles ahead of Firefox and Safari at time stretching audio. Firefox and Safari sound like an underwater mess. Chrome and IE use a sophisticated and very nice pitch correction algo (I think it is called WSOLA)

Wow, I had always assumed that the time-stretching was done server-side. I'm such a dinosaur.

Yeah, the whole advantage to HTML5 video is that it's just a video in a standard format. Your client (browser, whatever) can do whatever it likes with the video. Usually the UIs just present pausing, rewinding, maybe time-stretching. But in theory it's just a video and you can do any kind of analysis and editing on it you want.

I didn't realize the Flash version did not have this feature. I really want to echo this. I think this is the most useful feature to use for watching lectures and talks. I find for most things 1.5x is very usable and allows to quickly soak up content. Occasionally, 2x works well but many times its a bit too much. Coursera also allows this; I think Udacity does, as well. Take advantage of it.

Does any one know if there is a super easy way to also eliminate silent portions of the video? For example copying notes, changing blackboards, pauses in speech, erasing blackboards, etc? I feel like this could achieve similar results as 1.5x without as much strain, or could make 1.5 even faster. Bonus points for removing like, umm, uhh, etc

At some point, the author of the video has to take some responsibility for editing. This is like asking "Is there a super easy way to eliminate spelling errors on arbitrary web pages? Sometimes the author has no idea how to spell."

Actually, come to think of it, both are good ideas.

Did the Youtube Comment Snob people ever do anything more with that idea?

Not super easy, but should be doable using Web Audio API and its AnalyzerNode.

I never noticed this. You just made my week good sir!