Cool solutions

When you need to distribute documents in PDF format, you’ll probably want to protect them. If you are working on Mac OS X (or Windows) and you have Adobe Acrobat, that can be done quite easily.

But if you’re running Linux on your desktop —or even if you’re using Windows or a Mac and don’t want to use proprietary programs—, there are free tools that will let you protect your files by adding encryption, passwords and restrictions.

One of those tools is pdftk (the pdf toolkit). On Debian and Ubuntu, pdftk is already present in the official repositories, so all you have to do to install it is:

apt-get install pdftk

In the product’s website you’ll also find binary packages for FreeBSD, Mac OS X and Windows.

Here are some examples that show you how to use the program:

• Encrypt a PDF using 128-Bit Strength (the default) and withhold all permissions:

  pdftk mydoc.pdf output mydoc.128.pdf owner_pw foopass

• Same as above, except that a password is required to open the PDF:

  pdftk mydoc.pdf output mydoc.128.pdf owner_pw foo user_pw baz

• Same as above, except that printing is allowed (after the PDF has been opened):

  pdftk mydoc.pdf output mydoc.128.pdf owner_pw foo user_pw baz allow printing

Besides the security functions, pdftk has many more features that you might find useful too, including the ability to merge, split and rotate PDF documents, or applying watermarks.

Defined tags for this entry: cool solutions, floss, foss, pdf

Posted by Marcus Friedman

Broadcatching can be defined as the downloading of digital content that has been made available over the Internet through RSS feeds. Instead of having to spend time visiting multiple websites to find the contents that you want to download, you just need to find a relevant RSS feed and add it to your broadcatching client. The program will monitor the feed, and when it finds new contents it will let you know, allowing you to start new downloads with a single click. You can even tell the broadcatching client to download new contents for you as they become available, so the whole process becomes fully automated.

If you want to know how to take advantage of broadcatching by using open source programs (on Linux, Mac OS X or Windows), please read on.

Continue reading "Broadcatching with open source tools"

Posted by Marcus Friedman

Are you tired of searching endlessly for the files you want to download? Are you sick of waiting at the direct download sites for the files to start downloading? Have you ever spent hours downloading a video, only to find that its quality was rather poor, or that it was a fake? Have you ever wanted to be able to download videos from sites like YouTube, Megavideo or similar ones, instead of having to watch them with their embedded Flash players? If you answered “yes” to any of those questions, then read on.

Today we’ll talk about some pretty cool programs designed for making the find-and-download process as quick and painless as possible. Most of the programs we’ll mention are multiplatform, meaning that you’ll be able to use them not only on Linux but also on Mac OS X, Windows and may be other platforms too.

This article is organized in four sections:

• Direct downloads from one-click hosting servers
• Peer-to-peer file sharing using BitTorrent
• Downloading streaming contents
• Broadcatching (a brief introduction, with a full article on the subject coming soon)

Continue reading "How to download anything you need using open source tools"

Posted by Marcus Friedman

When it comes to vector graphics, there are many good choices available for the GNU / Linux platform. Xara Xtreme and Inkscape are two of the most popular programs in that category, and both are open source.

However, most vector drawing programs on Linux don’t allow you to import CorelDRAW files. If you’re into graphics design and if you’ve been working on Windows until now, that may be an important limitation.

Fortunately, there are several options to consider:

• sK1 : sK1 is a project that forked from Skencil around 2003. The sK1 developers began researching the CDR file format on December 2006, and released an import filter together with sK1 at the LGM (Libre Graphics Meeting) in 2007. By using sK1, you’ll be able to import your Corel drawings.
  
  

Continue reading "How to convert CorelDRAW files to open formats"

Posted by Marcus Friedman

Introduction

In this article we’ll take a look at how to convert videos for viewing them on different kinds of portable media players, including:

• iPod and iPhone
• Rockchip based players
• Players using the SigmaTel Motion Video format (SMV)
• Players using the AMV format

We’ll be using tools available for the GNU/Linux platform.

iPod and iPhone

If you need to convert video files for viewing them on your iPod or iPhone, there’s a program called mp4ize which automates the whole process. It’s a ruby script developed by Thomer Gil.

You can download the script from here. Using the script is really simple. Here’s an example:

mp4ize movie1.avi movie2.asf movie3.mpg ...

If you need to convert videos for the iPhone, then you must add the —iphone option to the command line, like this:

mp4ize --iphone movie1.avi movie2.asf movie3.mpg ...

Rockchip based players

There are many mp4 players that use a chip manufactured by Fuzhou Rockchip Electronics, generally known as the Rockchip.

These players support the ubiquitous AVI file format. Or at least, that’s what most manufacturers using this chip want you to believe. The truth is that you can’t just play any avi file. The videos must be encoded at a specific resolution and frame rate, using h263 as the quantizer type. If they aren’t encoded that way, it’s quite likely that the device will tell you that you are attempting to play a file with an invalid format.

Fortunately, video files for Rockchip-based mp4 players can be converted quite easily with a powerful command line tool that we covered before : mencoder.

Here’s an example that you could use in order to convert a standard avi file into one that’s supported by the mp4 player:

mencoder -noodml INPUT_VID.avi -of avi -o OUTPUT.avi -ofps 15 -vf-add scale=160:-2,expand=160:128 -srate 44100 -ovc xvid -xvidencopts bitrate=400:max_bframes=0:quant_type=h263 -oac lavc -lavcopts acodec=mp2:abitrate=96

You could also add some options for including subtitles (please see the article on DVD authoring for some examples handling subtitle files).

After the conversion is done, you’ll find that an hour of video takes around 112 MB of space. So in theory you’d be able to store more than 15 hours of video on a 2 GB device.

Continue reading "How to convert videos for your iPod, iPhone and other MP4 players"

Posted by Marcus Friedman