Adventures in Vector Quantization

Ever since seeing Radio Dada by Rosa Menkman I’ve been forever trying to reproduce the style of compression/glitches it uses.

In my limited knowledge about the production of the video I do know what it uses compression artifacts found in the Cinepak codec. So, I set out to try and find a way of converting a video to a video that uses the Cinepak codec. If you’ve been following me you’ll that I’ve asked for help on many fora and mailing lists for help with initially little success.

Hidden somewhere in the documentation for MEncoder is a page detailing how to use Windows codecs on Linux for encoding. The copy of the Cinepak codec (iccvid.dll) that came with MEncoder/medibuntu was a bit broken so I had to use Google to download a new version.

Once I had that I used MEncoder to convert a video to an avi with the Cinepak codec. (I’m using mencoder version 2:1.0~svn33951~natty):

[sourcecode language=”bash”]mencoder infile.avi -ovc vfw -xvfwopts codec=iccvid.dll -oac mp3lame -o outfile.avi[/sourcecode]

Unfortunately for me this did not produce the compression artifacts that I was after. I tried reencoding the video using the Cinepak codec several times but this only just made the video darker:


(Original video)

Also, my attempt to encode the video using the Cinepak codec but with a low bitrate didn’t work as, at least when using MEncoder, the codec doesn’t have any encoding options. Drats! With that said, if anyone knows of a way of encoding using Cinepak with low/different bitrates on Linux using only freely available/open source software please do let me/the world know.

After this I felt very disheartened until I did a little bit of digging into the actual codec. I discovered that this codec is one of a few is based on Vector Quantization. I don’t know much about this but I felt that this must be the key. The video codecs that are based on Vector Quantization are Sorenson, Indeo and VQA.

I had no luck finding a way of converting to Sorenson and Indeo. However, I’ve had more luck with VQA. Wikipedia has a bit of information on the codec:

Vector Quantized Animation, known by its acronym VQA is a file format originally developed by Westwood Studios for video encoding in their game The Legend of Kyrandia and monopoly.

If you ever came across a Sega Saturn you probably will have come across videos encoded using VQA. As that Wikipedia article states, apart from the one used by Westwood Studios, only one VQA encoder exists. VQA Encoder v0.5 beta 2 by ugordan is the only known VQA encoder and luckily it works perfectly using Wine (I’m using version 1.2.3-0ubuntu1~ppa1) on Ubuntu 11.04. You’ll have to download some additional DLLs. Just do some research to find out which ones.

In order to use the software you need to convert your video to image files. I’ve had luck with converting the video to PCX files using FFMPEG:

[sourcecode language=”bash”]ffmpeg -i infile.avi -sameq outfile_%03d.pcx[/sourcecode]

Then, in the VQA Encoder v0.5 beta 2 copy these options:

VQA encoder options

The program will automatically recognise that there are many images in the folder. After encoding has finished you should have a file called out_.vqa. In FFMPEG execute:

[sourcecode language=”bash”]ffmpeg -i out_.vqa -sameq outfile.avi[/sourcecode]

You should now have a video that has similar compression to the Cinepak codec used with low bitrates:


(Original video)

Brilliant! Well, not so brilliant. The problems with using this software are the following:

  • The software is no long being updated
  • Because of this it could stop working at any time and no support would be offered
  • It can only output video at 640×400, which you can see by the way it crops the video
  • It isn’t open source, though that only matters if you exclusively use open source software

So, is there any other way to achieve these compression artifacts, preferably using open source software?

What Glitch? scripts

For the What is Your Glitch? videos I wanted to build up on some of the extensive work that has already gone into the documentation, deconstruction and glitching of file formats. Rosa Menkman has already done a great job of documenting some of the more well-known file format glitches in the Vernacular of File Formats, which I recommend you all read. For this exercise I wanted to explore some of the more obscure file formats. Using open source software and Ubuntu has given me access to a wealth of programs that can still generate obscure file formats, such as pcx, pix and sgi. Through these experiments I also found inconsistencies in the way that different programs generate files, which is evident through my decision to use GIMP to convert files rather than Imagemagick in some of the scripts. Enough chit-chat, download the scripts!

Code hosted on GitHub

The method of glitching used in most of the scripts is the much-documented find and replace method. If you take a look in the scripts – and I encourage you to do so – you can change the characters that are being searched for and replaced. I’ve simply chosen characters that are sure to get results and are less likely to completely destroy the file.

Required Dependencies

Each script has its own set of dependencies, but to ensure you can run each one you’ll need the following:

  • Sed
  • GIMP – I use 2.71 beta available for Ubuntu from this ppa. Other versions remain untested
  • Imagemagick
  • GlitchSVG
  • FFMPEG
  • Mplayer
  • WebP

Basic Usage

1. Make the file executable: In a terminal type chmod+x [name of script] (e.g. what_glitch_webp.sh)
2. Run ./what_glitch_webp.sh in a terminal window
3. Drop a video file into terminal window and press Enter
4. Get a cup of tea

Notes

  • The scripts have only been tested on Ubuntu 10.10. If you are able to get them working with other operating systems please feel free to share your techniques
  • These scripts seem to work best with avi video files that are 24 or 25 frames per second. Files that are 30 frames per second get out of sync with the audio
  • Make sure the name of the directory containing the video to glitch doesn’t contain spaces e.g. “untitled_folder” instead of “untitled folder”
  • The video needs audio order for this script to work. If you know what you’re doing you can edit parts of this script for it to work on files that have no audio
  • As these scripts processes each frame of a video file it will take a very long time to complete. It is recommended for use only on small video clips!

These scripts by no means even begin to cover all of the image file formats available. There were a few formats that were not as easy to batch-process or were simply too large to process, such as xpm and xbm. For these you’ll have to do it manually or explore other ways of batch processing. They’re also not the most efficient of scripts. Some way into processing 400 video frames the script would slow down a lot. I welcome any bug fixes or suggestions on fixing this 😉

There’s still plenty of undiscovered glitches out there in the wild just waiting to be hunted down and exploited. I encourage anyone, everyone and their mother to pick from this long, but by no means complete list of image file formats and to find a way to glitch them!

Echobender

Myself and Mez recently finished a script called Echobender that automatically databends images.

Click to view on GitHub

To use it you’ll need:

  • A computer with Linux installed. I don’t have a Windows or Mac PC so I can’t test it on those
  • Sox. On Ubuntu you can install it via sudo apt-get install sox
  • Convert, which is part of ImageMagick. On Ubuntu you can install it via sudo apt-get install imagemagick

Once you have those installed just execute ./echobender.sh from the terminal and then drop a .jpg or .bmp file into it. The output will be in a folder called “echo”.

If you look closely at the script you can see a way to convert any data into an image! I’ll leave that one up to you… Here’s the source code for all those interested:

Thanks to Imbecil‘s MPegFucker script for much of the inspiration.

Databending using Audacity

Thanks to some help on the Audacity forum I finally know out how to use Audacity to databend. Previously I’d been using mhWavEdit, which has its limitations and just doesn’t feel as familiar as Audacity. From talk on the various databending discussion boards I found that people would often use tools like Cool Edit/Adobe Audition for their bends. Being on Linux and restricting myself to things that run natively (i.e. not under Wine) presented a new challenge. Part of my task was to replicate the methods others have found but under Linux. My ongoing quest is to find things that only Linux can do, which I’m sure I’ll find when I eventually figure out how to pipe data through one program into another!

Here’s some of my current results using Audacity:

Gabe, Abbey, L and me (by hellocatfood)

Liverpool (by hellocatfood)

Just so you don’t have to go trawling through the posts on the Audacity forum here’s how it’s done. It’s worth noting that this was on using Audacity 1.3.12-2 on Linux. Versions on other operating systems may be different. Before I show you this it’s probably better if you work with an uncompressed image format, such as .bmp or .tif. As jpgs are compressed data there’s always more chance of completely breaking a picture, rather than bending it. So, open up GIMP/your faviourite image editor and convert it to an uncompressed format. I’ll be using this picture I took at a Telepaphe gig awhile back.

Next, download Audacity. You don’t need the lame plugin as we wont be exporting to mp3, though grab it if you plan to use it for that feature in the future. Once you have it open go to File > Import > Raw Data and choose your file. What you’ll now be presented is with options on how to import this raw data, which is where I would usually fall flat.

Import Raw Data

Import Raw Data

Under Encoding you’ll need to select either U-Law or A-Law (remember which one you choose). When you choose any other format you’ll be converting the data into that format. Whilst you want to achieve data modification this is bad because it’ll convert the header of the image file, thereby breaking the image. U/A-Law just imports the data. The other settings do have significance but I wont go into that here. When you’re ready press Import and you’ll see your image as data!

Image as sound

Image as sound

Press play if you dare, but I’d place money on the fact that it’ll probably sound like either white noise or Aphex Twin glitchy goodness. This is where the fun can begin. For this tutorial select everything from about five seconds into the audio. The reason for this is because, just like editing an image in a text editor, the header is at the beginning of the file. Unless you know the size of the header and exactly where it ends (which you can find out with a bit of research), you can usually guess that it’s about a few seconds into the audio. The best way to find it out is to try it out!

Anyway, highlight that section and then go to Effect > Echo

Apply the echo

Leave the default settings as they are and press OK

You’ll see that your audio has changed visually. It still wont sound any better but the magic happens when you export it back to an image file, which is the next step.

Once you’re happy with your modifications go to File > Export. Choose a new location for your image and type in the proposed new file name but don’t press save just yet. You’ll need to change the export settings to match the import settings.

screenshot_11_16_110037

Change the file format to Other Uncompressed Files and then click on the Options button.

Export settings

Export settings

Change the settings to match the ones above (or to A-Law if you imported as A-Law). With that now all set you can now press Save! If you entered a file extension when you were choosing a file name you’ll get a warning about the file extension being incorrect, but you can ignore it and press Yes. If you didn’t choose a file extension, when the file is finished exporting, add the appropriate extension to the file. In my case I’d be adding .bmp to the end.

Here’s the finished image:

Freaky!

Freaky!

There’s of course so many different filters available in Audacity, so try each of them out! If you’re feeling really adventurous try importing two or more different images and then exporting them as a single image.

Comments on this post are now closed. If you need help on this try the Audacity forum

Ubuntu Bug Jam

Ubuntu Bug Jam

From Friday 2nd to Sunday many Ubuntu, Linux and Open Source enthusiasts descended upon the Linux Emporium to take part in the Ubuntu Bug Jam. In the words of an Ubuntu blogger, the Ubuntu Bug Jam is:

…a world-wide online and face-to-face event to get people together to fix Ubuntu bugs – we want to get as many people online fixing bugs, having a great time doing so, and putting their brick in the wall for free software. This is not only a great opportunity to really help Ubuntu, but to also get together with other Ubuntu fans to make a difference together, either via your LoCo team, your LUG, other free software group, or just getting people together in your house/apartment to fix bugs and have a great time.

This is the second time I’ve been to a bug jam. The first time I went I hadn’t even used Ubuntu, so only managed to report one bug and otherwise mostly focused on reporting stuff in Inkscape as I use it more often.

This time was a similar affair. Apart from testing out the beta of the next release of Ubuntu (the Karmic Koala) and asking for help in fixing bugs in my own system I mostly spent time testing bugs in Inkscape and suggesting features for future releases of Ubuntu.

Overall, I think reporting any bug in any package or program helps everyone and one thing I really like about open source is its transparency and honesty in its errors. That is, it’s not ashamed to admit that there are a few bugs here and there.

Making a Disco Ball using Blender and Inkscape

Awhile back I started doing a few experiments using Blender and Inkscape together. One of my creations from this was a ball.

Blender/Inkscape Sphere (by hellocatfood)

Recently one Inkscape user created a tutorial describing how to make a disco ball directly in Inkscape. Looking back at that ball that I made it kinda resembles a disco ball, so I decided to write a tutorial on how I did it.

This tutorial assumes that you know at least something about Blender and Inkscape. If not, go look at these tutorials for Inkscape and these tutorials for Blender. As with any program, the more you use it, the better you get at it.

We’re going to need three things before we begin. First install Blender. It’s available for Mac, Windows, Linux and probably any other system you can think of. Did I mention that it’s completely free? Next, install the VRM plugin for Blender. This is a free Blender plugin that allows you to export your Blender objects as an SVG (the file format that Inkscape uses by default). I’ve discussed the usefulness of this plugin before. Lastly, install Inkscape, if you don’t have it already. I’ll be using a beta build of 0.47, which should be officially coming out within the next two weeks. If not, just grab a beta build as it’s pretty stable.

Once you’ve installed these programs open up Blender and you’ll see the cube on screen.

The cube is usually the first thing you see.

The cube is usually the first thing you see.

Depending on how best you work you may want to switch to Camera view. You can do this by either clicking on View > Camera or pressing Num0 (the 0 key on the keypad). What we now see is what the camera sees. If you were to export this as a jpg or SVG this is the angle that you’d see it from.

oooh, shiny 3D!

oooh, shiny 3D!

We need remove this cube and add a UVsphere to the screen. Right-click on the cube and press X or Del to delete it.

Bye bye cube!

Bye bye cube!

To add a UVSphere, in the main window press the Spacebar and then go to Add > Mesh > UVSphere.

Add a UVsphere

Add a UVsphere

You’ll now see another dialogue box asking you to specify the rings and segments. This is important as it’ll define how many tiles there are in your disco ball. Think of these options in this way. The segments option is like the segments of an orange and cuts through the sphere vertically. The rings option cuts through it horizontally. These diagrams might explain it better:

Segments go vertically

Segments go vertically

Rings go horizontally

Rings go horizontally

Put the two together...

Put the two together...

The default is for both to be 32, but, if you want more tiles increase the value and if you want less decrease it. Once you’ve chosen press ok and your sphere should be on screen.

UVsphere

UVsphere

You can reposition, rotate or scale your sphere if needed. To reposition it, with the sphere selected (right-click it if it isn’t selected) press the G key. This grabs the object that’s selected and allows you to move it freely. Try moving your mouse about. This can be useful, but we’re working in a 3D environment which…er.. has three dimensions that you can move along. To move it along a set axis you can either left-click the arrows coming out from the sphere or, after pressing the G key, press the key that corresponds to the axis that you want to move it along. For example, if I wanted to move the sphere along the X axis (the red line) I’d press the G key, the the X key. Now, no matter how I move the mouse the movements of the sphere are constrained to the X axis.

Similarly, to rotate the sphere press the R key and to scale it press the S key. The same rules about constraining it to a certain axis can still apply.

You can do things such as repositioning the camera other such trickery but for that you’ll need to learn more about Blender for that.

With your sphere now ready go to Render (at the top of the screen) and then press VRM.

The VRM options window

The VRM options window

I left the options as they are, but if you feel adventurous have a mess around. When you’re ready press the Render button and then choose the place on your computer to save it and what name to give it and finally press Save SVG. You’ll notice the egg timer appears in place of your mouse cursor to let you know that something’s happening but otherwise there’s a handy progress bar at the top of the screen.

Blender Screenshot

Open up the saved object in Inkscape and voila!

It's an SVG Sphere!

It's an SVG Sphere!

That’s the first part of this tutorial done! The next part draws upon some of my own experiments but is also taken from the original tutorial.

When you’ve opened up the sphere you’ll notice that it’s all one object. This is because all of the paths (the tiles) are grouped into one. You can ungroup it if you want but for this tutorial you don’t need to. Give your object a base a fill and stroke colour. You can do this using either the colour palette at the bottom of the screen or the Fill and Stroke dialogue (Object > Fill and Stroke or Ctrl + Shift + F).

Applying fill and stroke colour

Applying fill and stroke colour

The final step of this tutorial from me is the following. With the base colour selected we’re now going to randomise the colours but within that hue. To do this we’re going to use the randomise filter which is located in (in Inkscape 0.47) Extensions > Color > Randomise.

Leave the Hue option unchecked (unless you want a multicoloured sphere) and then press Apply.

Your finished disco ball!

Your finished disco ball!

There is of course more that you can do to make this disco ball look more realistic but take a look at the tutorial that inspired this one and come up with something of your own 😉

Click to download the SVG

Click to download the SVG

Portrait for Nick Duxbury

I got a pleasant surprise today. Not even two days after publishing my post on basic portraits do I get asked to do a portrait.

Nick Duxbury

This is a portrait of Nick Duxbury an artist who used to be based in Birmingham but now resides in Scotland.

I used the same methods explained in my previous post except that I took the finished sketch into Inkscape to clean it up a bit. A good move considering the original picture had quite an elongated face!

Anything you can do I can also do

Recently at my job at any one time there’d be up to four different operating systems in just one room. There’d be Windows XP, which was on most of the computers, Windows Vista, which I used to dual boot, Ubuntu, my OS of choice and Mac OS X. I’d often have chats with one of my collegues about the differences between each operating system, and they’d always proclaim that Mac’s are superior to everything else. When asked why they’re so much better he could never give me an answer.

He’d show me his shiny interface, dock full of cracked Adobe software and impressively pointless window transitions. Then, I’d load up Compiz and do exactly the same. “That’s just copying Mac”, he’d say. So what? Mac weren’t the inventors of modern interface design y’know. I’d then show him the rotating desktop cube and one of the many other Compiz settings available. He was quite impressed and asked me how he could get those effects for his Mac. Wait, your precious Mac doesn’t have these features? What a shame. I paid only £500 for my laptop and can have more ponies amazingly kewl effects.

A few days later we had some visitors and he kept saying that Mac’s are better because they don’t get viruses. What a load of bull. As the popularity of Mac grows so too will the desire for crackers to write malicious code. Also, are Mac’s in a worse position than Windows when it comes to viruses? Mac users have rarely had to worry about viruses, so maybe its users are more inclined to just click on anything. At least Windows users are constantly being reminded of virus threats. This, of course, doesn’t equate to a more secure system but at least it educates users that the moment you put any personal or precious data onto a computer you are at its mercy and should take caution.

Linux will soon be in a similar position. As it yet isn’t big or attractive enough to crackers we’ve yet to see if the collective efforts of 1000s of coders is more effective than Norton, AVG et al.

This post isn’t a jab at Apple either. In fact, if I could afford to I’d probably buy a Mac laptop and just load Ubuntu on to it, not because it’s a better operating system but because, after using all three for awhile I’ve found Linux systems to do what I need it to and offer me a level of customisation to satisfy my needs. Oh, and it’s free. The Mac laptop is just a well designed piece of hardware and I could see why anyone would want that.

I’ve discussed my disliking for Operating System superiority complex on Twitter before. My argument was that all three major operating systems can do what the other can. After some great feedback regarding this I’d like to change that and say that all operating systems can do what the other can, the difference is just how you do it and how much effort is involved.