Although in its early stages it didn't support HD (well, it wasn't a big deal those days anyway) but with recent versions the video codec Theora can even handle HD resolutions as well.
I also remember in those early days there wasn't much GUI front-ends (there wasn't any!) available ... all we had those days was the command-line tool that Theora developers gave you. I remember vividly trying that command-line tool for the first time to convert a .MPG file and, although the output wasn't the best of its kind, but I was already impressed by its performance.
Time has passed and these days Theora has become a very powerful video compression tool nonetheless. As said it can handle HD videos too, but it tends to give better results at lower video resolutions (it's optimized for that).
Anyhow, if you want to convert a lot of other (both proprietary and free) multimedia formats into Theora ... then Oggconvert is a pretty decent application. The reason for that "decent" is because, the application does lack few features that are essential if you're serious about getting the best possible results.
|Not recommended for professionals... but can be pretty handy for everyday usages...|
*. Oggconvert, GUI is written in GTK+ toolkit (Python is the programming language) and is very easy to use.
*. Comes with "sliders" by using them you can switch between audio and video quality (defined by numbers - see the above screenshot).
*. If you want to change the container format, then click on the "Advanced" button and it'll let you use Ogg, Matroska and WebM formats.
*. Drag n Drop support + it uses the Gstreamer multimedia framework. So if you've installed the proprietary Gstreamer codecs... then Oggconvert can convert almost all the popular multimedia files!.
Well, that's about it. But as mentioned earlier, it would've been better if we were given the ability to crop, resize and enter video (especially) and audio bitrates manually... since they are the most important factors which define the quality of the output file, apart from the video compression format (codec) itself.
Anyhow, if you use Ubuntu 11.04 Natty Narwhal (including 10.04 and 10.10) you can easily install OggConvert by entering the below command in your Terminal.
sudo apt-get install oggconvertDon't worry. If you haven't done already, this will automatically install the Gstreamer proprietary codecs dependencies too. Enjoy!.