Hacking

Hacking

Lib-Ray Video Standard: Assembling the Matroska MKV container file with mkvtoolnix-gtk

In my previous installments, I described the success I've been having with compressing "Sita Sings the Blues" with the VP8 video codec, and at the end I had a video file. Then I converted the audio to get a FLAC copy of the soundtrack (opting to retain this rather than compress into Vorbis format). Now in this installment, I'll show how I used mkvtoolnix-gtk to build a complete MKV file with VP8 video, FLAC audio, and named chapters. The result is the complete "main feature" multimedia file that will form the core of the Lib-Ray prototype.

Lib-Ray Video Standard: FLAC and Vorbis codecs for Sound

In my previous column, I described the success I've had with using VP8 for compressing the video for the Lib-Ray main feature multimedia file. At the end of that process, though, I still have a silent film. We also need to get the audio, and make a decision about the format. WebM calls for Vorbis sound, which probably makes sense for internet downloads, but this is where we part ways -- for my application, bit-perfect audio with FLAC seems to make more sense, at least for the main audio tracks (Vorbis is still in the picture for things like commentaries).

Programming effective reminders in GNU/Linux

There are some nice sticky-note applications for Linux, and they're good places to write down reminders, like Ring Fred or Pick up a litre of milk.

Unfortunately, sticky-notes are no help to me at all. I'm often forgetful, and I'm more than likely to shut down my computer without checking to see if I've written a note to myself. To get around this problem, I wrote a couple of very simple scripts, each launched by an icon on my Xfce panel.

Lib-Ray Video Standard: Using Google/On2's VP8 Video Codec

When I started working on a no-DRM, open-standards-based solution for distributing high-definition video on fixed media ("Lib-Ray"), I naturally thought of Theora, because it was developed as a free software project. Several people have suggested, though, that the VP8 codec would be a better fit for my application. This month, I've finally gotten the necessary vpxtools and mkvtoolnix packages installed on my Debian system, and so I'm having a first-look at VP8. The results are very promising, though the tools are somewhat finicky.

Find duplicates and originals in a spreadsheet using the Unix command line

Sometimes, you need to find and group together the replicated records in a spreadsheet. There are several different ways to identify duplicated records (see this tutorial for a good one), but what I wanted was something a bit more fancy. I wanted not just the duplicates, but each original record as well. Furthermore, I wanted any replicates (original + duplicates) grouped together in neat little sets in the spreadsheet.

Here is how I did it using the Unix command line.

Debian/Ubuntu: Making a Package Repository on Your LAN

This is one of those things that doesn't get explained much, because it's almost too simple to document: it's often useful to keep a few Debian package files (.deb files, used in Debian, Ubuntu, and Linux distributions derived from them) available for installation, either on your local host or on other computers on the same local-area network (LAN). You can make these available as an extra "repository" for your APT system, so that APT-based package tools (apt-get, Aptitude, Synaptic, etc) can access them. This makes managing these special packages just like your other packages, which can solve a lot of problems.

Lib-Ray Video Standard: Moving to SDHC Flash Media

In Spring 2011, I started a project to attempt to create a free-culture compatible / non-DRM alternative to Blu-Ray for high-definition video releases on fixed-media, and after about a year hiatus, I'm getting back to it with some new ideas. The first is that I've concluded that optical discs are a bust for this kind of application, and that the time has come to move on to Flash media, specifically SDHC/SDXC as the hardware medium. This is a more expensive choice of medium, and still not perfect, but it has enough advantages to make it a clear choice now.

Generation of one-page, domain-oriented sites using PHP

A web site is a set of pages on a specific subject. It normally has sub-pages, and normally valuable information about the topic it covers. What if a web site is dedicated to a property? Could you create a web site focused on a specific property, and also named after the property? (something like 22birtonsthamiltonhill.com)? How would you create such a think based on free software? (At the end of this article, you should be able to create a complete template system and a site containing the full list of sites, for property sites.

Build your own special characters chooser

I often need to insert a special character in my writing, like the degree symbol or the Greek letter mu. Although LibreOffice Writer, my favourite writing application, helps me do this with an Insert special character function, it offers too many choices. There are only a few special characters I use regularly, and they're scattered across several font subsets.

The Completely Blank Xfce Desktop

The Xfce desktop environment comes with Xubuntu and is also available in the Xfce versions of Linux Mint, Fedora and other Linux distributions. Using Xfce, you can easily set up a highly functional but completely blank desktop - no icons, no menus, nothing. Just a blank screen or a favourite wallpaper, ideal for the user who hates distractions or loves simplicity. Here's how to do it.

Practical guide to TCP Syn Port scanner from SecPoint

Do you know if your server or your home computer has unnecessary ports open to the internet? These days most of the people have multiple devices which are constantly connected to the internet; each and every device comes with many services with open ports running quietly in the background. The user might not even have an idea of those services running, but the open ports often open new possibilities of threats from the outside world.

The tool portscanner created by Secpoint comes to the rescue: see how.

Python Scripting in Blender: A Piece of Pie - Part 1

Since script extensions are going to be a part of our toolchain on creating Lunatics, I thought it would be a good idea to familiarize myself with how scripts are created and run in Blender. As a learning project, I decided to create a script for creating 3D pie charts from CSV data files. My first task is to write this for Blender 2.49 using the API for Python 2.6. This is the version documented in the Python Scripting book from Packt that I recently reviewed, so it's a good place for me to start.

Archiving emails as text files, with command line help

Call me old-fashioned, but I like to store emails in text files, one per correspondent. For example, 'Bloggs_Fred.txt' contains all my emails to and from Fred Bloggs, in chronological order with the newest message last. Other people might have the need to periodically store parts of emails in predefined files (for example, when collecting information).

I wrote a very simple script to make this kind of archiving easier. Before I explain the script, I'll show you how it works.

What to do if your mail server is blacklisted

This article is not strictly about free software. In fact, it's not about free software at all: it's about what to do to find out if your server's IP is blacklisted for sending mail. I just discovered Valli.org as one of the things I had to do to sort the Free Software Magazine mailing list, and wanted to check why some of our emails were rejected. (Note: We are not affiliated in any way with Valli.org.) If you manage a Postfix mail server, this is a resource you cannot miss.

Mounting Google Documents in GNU/Linux is just not a (real) option

If you use Google Documents, you might want to be able to access your files without using a browser. So, I was all set, happy to write a good blog entry about how to mount your Google Documents folder on your Ubuntu. (This is not a very free-software thing to do, granted. But then again, if you are an Ubuntu One user, well, Ubuntu One server isn't free software either. But, it's a service, and interfacing to things is crucial.)

So, is it actually possible?

Encouraging the next generation of hackers part 2 - Software implementation

In the first part of this series I looked at the Raspberry Pi -- a $25 computer which is being developed to remove one barrier to encouraging the next generation of programmers. It's ambitious and commendable but on its own it may not be enough. The choice of software for such a project is important and as important is the implementation of that software.

Creating a Project Website for "Lunatics" with Apache, Zope, Plone, MediaWiki, Trac, Subversion, and the Cloud Too

Film is a very comprehensive art form, probably the most that we have available to us at the moment, so it should be no surprise that a free film project severely tests the limits of available free software, not only for authoring the film, but also for collaborating on its creation. In the case of "Lunatics", we need to combine some of the community development software that is frequently used for free software development with tools allowing a lighter-weight interaction more comfortable for creative contributors, and finally, a fan-friendly public face. It's tricky, and I don't think we're really all the way there yet, but over this Summer, I've managed to find and assemble the necessary parts for our online presence. My solution combines several different platforms, and uses a few remote or "cloud" services as well.

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