March 29, 2006

Get Thoggen, and leave your DVDs at home

Author: Nathan Willis

Thoggen is a new DVD ripper/backup-tool for Linux that encodes video into the free Ogg Theora format. Unlike its rivals, Thoggen is easy to use, and its built-in support for the Theora codec instead of the patent-restricted MPEG-4 and derivatives makes it worth looking at.

On its surface, Thoggen is a DVD backup and extraction tool (i.e., "ripper"). You use it to make a copy of the video titles on your DVD, either because you worry about damaging frequently played discs, because watching compressed video from the hard disk is faster and less power-hungry than watching it from a DVD drive, or perhaps because you simply need portability. The thought of carrying every episode of "Arrested Development" wherever you go is certainly appealing, but even slimline DVD boxed sets get cumbersome on a daily commute.

Some DVD extractors are limited to pulling content off of a disc as-is, leaving you with a set of gargantuan .VOB files. Others that take the next step, encoding the video in a space-saving compressed format. Most of these utilize a variant of the MPEG-4 Part 2 codec: XviD, DivX, 3ivx, et cetera.

The trouble is that MPEG-4 is patented, and in order to use it legally you need a license, even if you've jumped every other legal hurdle Hollywood throws at the public these days -- I mean content like public domain, unencrypted DVDs. Certainly there are people out there with nefarious ends in mind, for whom such issues make zero difference, but what about the rest of us? Well, thanks to Thoggen, we have a tool to extract and repackage DVD video in a royalty-free, patent-free format.

Ogg fans will remember Theora as the free (BSD-licensed) derivative of the On2's VP3 codec, donated by On2 to the foundation in 2002. Theora is actually a superset of the old VP3, rewritten to take better advantage of the Ogg container format and as a result be more flexible., home to development of the Vorbis audio codec, releases "reference implementations" of Theora as the libtheora library. It currently stands at 1.0 alpha5.

Many free software players support the codec, including mainstays VLC, MPlayer and Xine. Support in commercially available players is less common, although the RealNetworks-sponsored Helix Player does support Theora, and a package of DirectShow filters is available for Windows.

Let there be oggs

To use Thoggen, grab a package from the project's site. The current release is 0.4, and it's available as source code, but the download page has links to binaries for some older releases, so it is worth checking to see if new binaries appear there as well. I had no trouble compiling the source. The program relies on GStreamer and libdvdread3; be sure to check the dependencies.

Once installed, Thoggen is simple to use. Thoggen detects DVD drives on your computer and, if you have more than one, lets you select which one to extract. From the selected disc, it presents you with a checklist of the available title tracks.

Here there is a shortcoming, in that you must decide which titles to rip without benefit of their names. Most CD rippers handle the analogous situation by connecting to an online database like, but there is no such site for DVD content.

After you choose which tracks to rip, Thoggen will bring up a simple options page where you can select language tracks (if available) and set your output video options. You have your choice between multiple picture sizes, the ability to crop the picture, and the option to set either a video quality parameter or to restrict the output size. Last but not least, you can choose to add a title tag and specify the name of the output file.

Once you are ready, click OK. Thoggen handles the rest of the configuration details, and brings up a preview window so you can keep an eye on the ripping progress.

Do one thing and do it well

Thoggen is not perfect, of course. Several times when testing it, the ripping process kept churning long after the encoding was finished -- a known bug in this release. And that encoding process is CPU-intensive and very long. The Theora implementation used is far from optimized, and at full DVD resolution, encoding can slow down to the single-digit frames-per-second count, meaning several hours are required.

That said, I still recommend Thoggen. For one thing, I can't heap enough praise on the interface. Simplicity is the watchword, and Thoggen gets it just right, presenting the user with the appropriate choices and working out the necessary details itself. Transcoding video is complicated, but Thoggen manages to make it simple. A lot of other apps could learn a lot from its design decisions.

I also like the fact that Thoggen uses Theora; this is good for users because Linux distributions can ship it, and good for the ongoing development of the codec as well. Detractors may say that free codecs like Vorbis and Theora are bound up in a "chicken and egg" dilemma: the older codecs are better performers because everyone uses them, and everyone uses them because they are better performers.

Maybe so. But Thoggen is the best and easiest to use DVD video extractor out there, and that alone is reason enough to use it; the fact that it uses a free, patent-unencumbered codec is immaterial to users. But by virtue of being an excellent application, it will accelerate both adoption and development of the codec. And then everybody wins.