_U-LAW one shot

to start, i'm already sorry for my english level... [ as people use to say now, "English Level : French" ]

First, you'll need Audacity in order to perform all the following stuffs, so take it here :

So here it is ! I'll tell you how to generate glitching video really simply (no coding, no play in HexEditor, just some clicks and lot's of encoding and decoding) ! if you are here, then I don't need to explain you what is a glitch, and I won't run into technical explanation about U-LAW, A-LAW, video compression and stuffs. if you're curious about it, there is still that good guy of wikipedia around here.

I'm doing this little tutorial cause I spent lot's of time working on generating glitching videos, and around 80% of this spent time leaded to unreadable/unusable video files, so there is no need for everybody to do the same mistakes!

Ok so, no more chatting, here come the glitch!

You'll need your source file that you wanna glitch, obviously a video file, but it needs to be "pre-encoded" using specific codecs, and each of those specific codecs lead to different kind of glitch (see the gallery below to see what kind of glitch you wanna do and so what kind of codecs you'll use). And just Use your favorite encoding program (like SUPER, AviDemux, VirtualDub, or even After Effects etc...) to encode it.
The smaller the video is, the faster Audacity work on it. But as there tons of different codecs, there are some that are really not powerful for video compression and give you huge files, but for some of them, you'll get astonishing glitches !!

Many obsolete codec are a bit hard to find in fact so a good way to get them is to download an early version of FFDshow with obsolete or buggy codecs (they were removed from it now) :

as an example of buggy codec, here is what I get (without doing anything more than exporting it !) from my source by encoding it using this early FFDShow MPEG-1 codec :

buggy mpeg-1

Don't be afraid to play with the codec configuration also, while encoding your source file ; for example some codecs allow you to choose Keyframes interval, colorspace type, global image quality (bitrate) etc... which has definitely an influence on the glitch you'll get !


Here the small step-by-step method :

1_ open Audacity
2_ file/import/Raw Data -> then choose your video file
3_ (in the pop-up window) Encoding -> slide down to U-LAW
4_ (still in the pop-up) Channels -> put just one ( 2 aren't needed, and don't make big difference)
5_ then wait a bit (depending on the file size, i've tried on 7GB files and got to wait around 8 minutes...)
6_ then you should see a wave form of your files, don't change anything on it
(we'll see how to play with it on the next tuto)
7_ file/export
8_ type -> choose "other uncompressed..."
9_ click "options" : choose RAW(Headerless) and for encoding, be sure to stay in U-LAW mode
10_ change your file name (to not overwrite your source file) and replace the ".raw" at the end by ".avi" if the source was an avi file, mp4 if it was an mp4 etc....
11_ then export it ! (click ok on pop-up windows that warn you about raw compatibilty stuffs)

so you got your glitched video ! (that's why I call it "one shot" cause there is nearly no manipulation or control over it, just launch process, wait and get it).

Now open it in VLC or MPC (or whatever you want, but choose a solid player) and enjoy it ! to convert it in a solid file, just put it back in your encoding program and export it again ( in my case I use AviDemux to put it back into x264 *.mp4 to upload it, or even you can import it into your compositing program like after effects or Finalcut to use it in a project...)

For some reasons (cause players work in different ways) you'll get sometimes differents results while opening your glitched file into VLC or MPC etc... so If you like what you get into VLC and not what you see in MPC, then export it again directly from VLC for example, which will give a solid video file of what you saw in it, and if VLC can open it but crash while re-exporting it in a solid file, don't hesitate to use video capture program like FRAPS to record what VLC is showing, because sometimes, capturing a glitch in clean file can be seen as the main part of the job cause glitches are like wild animals in a certain way, you can see them, but putting them into a clean video file structure is a mess.


So here is the biggest part ! gallery of glitch i've done with this method, Each Codec used are mentionned on the "button". All those codecs comes on most of the encoding program, some are obsolete, but can still be found around the net (if you see a codec here that you don't have, just google it and you'll find it easily). It's also kind of interesting to see here that codecs works in a really different way from each others, cause you can imagine in glitches the compression structure of each one...

I used as base video, one of the most colorful and annoying video I found : the Lucky Star opening (japanese animation).

The first set is made from a 720p source file, and the second one from a low def version of this file and are a bit runny (I did it cause some codecs doesn't like to be glitched in HD),


microsoft Video1
microsoft RLE

720p snapshots

ms Video1
qt mpeg4
qt unc
ms RLE
qt animation


divx 6.8
mp4 (from youtube)
mpeg2 indexed
mpeg2 not indexed
microsoft RLE
microsoft Video1

there are a lot more codec to try ! i've tried some other ones but if they don't appear here mean that it leaded to unreadable files (like quicktime JPEG2000, HD FFV1...). Anyway, feel free to try them cause glitching video using this method is really random, and sometimes it works, some times not (with same file, same codec) for example, my HD flv version worked after several tries, and the result has a broken index not far from the video start, but can still be opened, and the result is quite nice. I'll also add more test with other codec soon.

Conclusion is, making glitch is finally (in this way) no big deal, so the point is to find what to do with those animated creatures ! _________________________________________________________________________

So now, here is preview of the next chapter i'm working on about controlling video files destructuration (still in audacity) ! preview is a bit runny but source file is really sharper, see the snapshot


and the third chapter to come is about mixing different video together while making them glitching, still in audacity (powerful sandwishes !)

_A-LAW amplification play

_...more to come

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