Save Time by Speeding Up Videos

This is going to be a small, technical tutorial on how to save a lot of time by watching videos at higher playback rates.

I first read about this idea from my most favorite personal development blog at Steve In his post "Overclock Your Audio Learning" he says that he occasionally listens to audios at 4.1x. At this speed 4 hour video/audio can be listened in less 1 hour!

I personally found it impossible to understand anything at 4x speed. My optimal listening speed is 1.65x - 2.1x.

To speed up the videos you will first need to download and install AviSynth. AviSynth is kind of a video programming language with which you can do all kinds of manipulations to videos programmatically. If you are on Windows, then during the installation make sure to associate .avs file extension with Windows Media Player and not Notepad.

Next, create this AviSynth script, and place it in the same directory as your video. Name the script as "speedup.avs" or something similar. Make sure the extension is ".avs" if you are on Windows!

file = "file_name_of_video.avi"
speedup = 1.65
pitch = 100


audio_rate = last.audiorate
video_rate = last.framerate

TimeStretch(pitch = pitch)

There are three variables that you can change in this simple script. The first is "file". It should be the filename of the video you are about to watch. The next is "speedup". It's the new playback rate, you may set it to any value you wish. For example, if you set it to 2.0, then the video will play twice as fast as it normally would. And the last parameter to change is the "pitch". You may change it to something lower than 100 when the video plays at higher speeds to make the speaker sound lower. I usually keep "speedup" at 1.65 and "pitch" at 75.

Once you have made your own configuration, just double click the .avs on Windows to play it at the new playback speed, or play it through mplayer on Linux!

Update: My blog readers bobb and crb suggested two new techniques on how to watch videos faster. Bobb suggested just to use mplayer. Turns out it already has an option to play videos faster!

mplayer -speed 1.65 file.avi

# use keys [ ], and { } to control the playback speed
# use backspace to reset video speed to normal.

Crb suggested to use MySpeed™ Plug-In for YouTube to speed up video on YouTube in real time.

Here are a few examples that I crafted at speeds 1x, 1.4x, 1.65x, 2x, 2.25x, 2.5x, 2.75x and 3x. They are from Alan Kay's keynote speech "The computer revolution hasn't happend yet" at OOPSLA Conference in 1997.

After a few minutes of listening at higher speeds, try going back to listen at 1x. It will seem incredibly slow because your mind will have adapted to the faster input rate.

Alan Kay's talk at a normal speed. Total time: 5 mins.

Direct URL:

Alan Kay's talk at 1.4x speed. Total time: 3:34 mins.

Direct URL:

Alan Kay's talk at 1.65x speed. Total time: 3 mins.

Direct URL:

Alan Kay's talk at 2x speed. Total time: 2:30 mins.

Direct URL:

Alan Kay's talk at 2.25x speed. Total time: 2:13 mins.

Direct URL:

Alan Kay's talk at 2.5x speed. Total time: 2 mins.

Direct URL:

Alan Kay's talk at 2.75x speed. Total time: 1:49 mins.

Direct URL:

Alan Kay's talk at 3x speed. Total time: 1:40 mins.

Direct URL:

Do you have any other techniques to speed up videos? I am also curious at what speeds do you feel the most comfortable watching the videos?

It would also be cool to create a hack that modifies youtube and google video players to make them play videos faster natively.

Ps. Did you know that I was a big fan of video lectures? I have been collecting math, physics, computer science video lectures for almost 3 years now and posting them to my other Free Science Online Blog.


January 07, 2009, 20:53

I watch videos in QuickTime (Pro) at double speed. QuickTime essentially resamples (maybe skips?) every other frame. The net result is that you get through the movie or audio clip in half the time, but without changing the audio pitch—it's *much* easier to listen to (and understand) than Alvin and the Chipmunks.

January 07, 2009, 20:55

I should add that I haven't tried saving a video/audio clip at double speed in QuickTime (and wouldn't know how). I just watch it on my own player at that speed.

January 07, 2009, 20:56

Good idea, Scott! I hadn't thought about it. I think it's certainly possible to do it with AviSynth (make it skip every 2nd frame). Will try and update the post with my findings, if any.

Aleksey Tsalolikhin Permalink
January 07, 2009, 20:57

I find it useful when you can adjust the speed-up rate as you watch the video - then you can "ramp-up" your speed - go from 1 to 1.4 to to 1.8 to 2.2 to 2.5 -- whatever your top speed is.

This is more effective than jumping from 1 to 2.5 directly - you wouldn't be able to follow 2.5 this way, but if you ramp up, you can.

January 07, 2009, 21:05

Aleksey, I wish there was software that did it smoothly. I just had a chat in #perl and some guys told me that mplayer does it natively (try pressing [ and ] keys while viewing video). Didn't know that before.

I usually start at 1.65x, then ramp-up to 2x if the speaker is a fine orator.

January 07, 2009, 21:08

Scott, it is trivially easy to save - use ffmpeg and filter the input video via my AviSynth script:

ffmpeg -i speedup.avs output.avi
Zach Permalink
January 07, 2009, 21:12

Been doing this with mplayer for a while, but it's more cpu intensive the faster you go.

Eric Permalink
January 07, 2009, 21:14

If you are using Windows Media Player just go to View -> Enhancements -> Play Speed Settings

It speeds up the video but the audio stays the same pitch so you don't get the chipmunk effect.

I also think there is a way to use FFMPEG directly to re-encode at a faster speed. You may want to look into that.

Toronto Permalink
June 11, 2010, 15:16

hey eric, where is the "view" bar on windows media player. studying for medical school board exam, this would be crucial.

January 07, 2009, 21:17

How do you use that, Eric? I tried on both my Windows XP machines and there is no slider on that speed control. But it also does not look like a regular slide control either, so I am confused.

Eric Permalink
January 07, 2009, 21:24

@Peter I think it only works for certain video codecs. I don't remember which ones work and which ones don't.

alexandru Permalink
January 07, 2009, 22:00

i'm not a native English speaker and at 1.65x I have trouble understanding, but at 1.4x seems reasonable (but still requires more of my attention).

anonymous Permalink
January 07, 2009, 22:14

You can use } and ] to speed up and { and [ to slow down in mplayer. That might be useful only if you're downloading and saving videos to watch on your own time.

stewart Permalink
January 07, 2009, 23:26

I've been doing this for years now; since most of the videos I watch have subtitles, I'll skip a few seconds forward in each file I watch to catch the next subtitle as it appears on the screen. I can usually watch a 45 minute clip in about 15 minutes this way, and you don't have to worry about the chipmunk sound effects.

January 07, 2009, 23:54

Hey Peter, the rss feed on your science blog is not working and there's no feed on

I would like to subscribe to both.

bobb Permalink
January 08, 2009, 01:21

You should really update this post with a "Just use mplayer" comment, save people the effort.

mplayer -speed 1.65 file.avi

Or use the {,[,],} keys during playback as already mentioned. Also resets speed to 100%.


- bobb

crb Permalink
January 08, 2009, 02:58

It took me a long time to find a system to do this that I liked. Here's what I do:

1. Convert video to wmv if needed with Quick Media Converter (

2. Windows Media Player speed settings as noted in a previous comment. WMVs are the only videos I know will always work with the speed adjustment.

Also, all Flash-based web players that I've seen (YouTube etc.) can be sped up with the MySpeed plugin (

January 08, 2009, 08:16

Thanks bobb and crb. I updated the post to include your comments!

January 08, 2009, 17:50

I use the Enounce MySpeed Plug-In that lets me speed up or slow down the Flash video in real time right on the website without downloading or converting the video to AVI format. I can also download and playback the FLV file with RealPlayer and MySpeed speed control appears and lets me control the speed of downloaded content as well.

January 08, 2009, 18:05

Yeah, Chris! I just installed and tried it, it's awesome!

wunar Permalink
January 08, 2009, 19:35

It looks to me that very good additional improvement could be achieved by stripping (or intensively speeding up) <strike>whitespace most of the silence. It would require video preprocessing, though, and wouldn't be as trivial as -speed parameter for mplayer.

January 09, 2009, 15:54

Vlc has a slider for speed contol. and lets you zip through stuff quickly.

Marek Kubica Permalink
January 10, 2009, 01:19

Take a look at these comments here.

mplayer -af scaletempo -speed 1.4 filename

does the trick quite nice for me and is way easier to listen to.

troll Permalink
March 27, 2009, 19:25

Drill a hole in your skull and plug in cable with rj45 connector! some say, thats the way you insta-download all internets, including all pr0n!

rolly Permalink
June 10, 2009, 20:22

Dude, some day you will discover girls and you will realise that you have wasted your life.

July 01, 2009, 00:39

I use VLC to playback videos at higher speeds. It's free and available on any platform. It has << and >> buttons for increasing and decreasing the speed. It keeps the pitch at the same level at whatever speed you're listening.

omer Permalink
September 14, 2009, 17:06

Gom Player and VLC Player have speed up feature.

omer Permalink
September 24, 2009, 18:44

I found this plug-in for real media

October 07, 2009, 22:04

Can't say that I watch that many educational vids, but I never thought of doing this speeding up stuff.

Even though, the chipmunk effect is rather annoying, it annoys me more when some crappy speakers go "umm... $word ummm $second_word ummm", etc. On higher speed that's not that apparent :)

I'm not a native English speaker, and the video on which I tried the speed was spoken by Italian guy with semi-broken English; I couldn't understand everything at x1.6, but at x1.4 it was just fine.

December 27, 2009, 02:16

I have used your code with great success and thank you for putting it online. Now I find myself trying to find out how to slow down the video (slow motion) and also having the sound slow down too. I have seen some already with a person laughing and the audio sounds really creepy. That is the effect I am going for. What would I need to change on the script to slow down video and audio? Thanks..

December 29, 2009, 15:57

Gerrit, the script that I posted slows down both the audio and the video! You don't need other software.

Jack Permalink
January 09, 2010, 04:55

Tried the AviSynth script with a MIT linear algebra mp4 file on Win 7 with MediaPlayer 12, and it sped up the video, but no sound. I like the idea of controlling the pitch. Any suggestions?

Jack Permalink
January 09, 2010, 04:59

...well works with a .avi file. I guess the solution is to convert mp4 to avi.

January 09, 2010, 06:23

Jack, I don't know. I'd have to tackle with it myself to find out why it doesn't work.

nun0 Permalink
July 01, 2010, 01:53

the plugin software called "Enounce 2xAV Plug-In for Windows Media Player" may answer all of your question

June 06, 2011, 09:01

can you do you do this with lnx/mac without downloading the each video

Sm40 Permalink
January 10, 2012, 14:12

The only problem with this entire thing:

The pitch of his voice is almost chipmunk-like.

Henrik Nilsson Permalink
February 21, 2012, 19:28

Now youtube vids are possible to play faster with HTML5. Found this at my next search:

Maxim Khesin Permalink
February 22, 2012, 14:30

On iPad AVPlayerHD does this really well for many formats. See (I'm a satisfied customer, do not work for them :-p)

John F Permalink
March 19, 2012, 02:08

An easier way is to download youtube video with and play the video with VLC Media Player. Use the right bracket key to speed up the video and left bracket key to slow down (press = to reset speed)

September 18, 2012, 16:39

If you wanted to speed up playback on your iPhone or iPad, even directly from websites like YouTube, you should try Swift Player.

Moustafa Permalink
May 16, 2013, 15:22

It might be a new feature, but in windows media player you can just right click on the video you are playing, select enhancements -> play speed settings. The audio pitch stays the same like this also.

Devon Permalink
September 04, 2014, 18:22

Lol I thought I was the only one doing this. Is it possible to speed audio up without having that chipmunk effect? Now youtube has the speed setting for each video, so I'm about to save a whole lot of time. I almost can't go back to normal speeds anymore.

zardilior Permalink
January 22, 2015, 22:16

I actually believe its easier to go from 1-> to 2.5x or very high and stay like that a while even if you don't understand then once you drop to 2x it sounds normal. Also the chipmunk effect is eliminated once you get accustomed and start listening as if it was normal speed

Mao Permalink
April 25, 2015, 20:33

Dear friends,

too much efforts.
I have used Light Alloy player - you can choose the speed of video. It is working great, but there was a problem for me - you can choose 0.1-2x speeds and after only 3x, 4x, etc. I wanted to have smth in between (like 2,5x).
After some search I have found KMPlayer - just great. When installed, you can use SHIFT&NUM&+ combination to increase speed for 5%. Just try it. Good luck!

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