As I wanted to (for the first time) convert an MP4 video to a patent free version with OGG Theora I found that the solutions is simple. There is a command line tool “ffmpeg2theora” for Unix systems. This is part of “OggConvert” and sure is available for many Unix based operating systems.
I started “GNU Screen” from command line which enables me to close the terminal at every point without ending the conversion process. This is often smarter than using some GUI tools which might break more easily. With this process you can even reset your session without stopping the conversion. I then just typed “ffmpeg2theora filename.mp4” and it will produce a file named “filename.ogv”.
What I just describes is no magic at all, but plain and simple.
Again Why Theora?
Because Theora is patent free. So nobody who is watching the file will ever need a license to play it. You should consider using Theora. Firefox 3.5 will support playing it without any plugins! Its the new free video standard of the internet.