I needed to convert some video clips from format A to format B. (The video clip started as an OGG format)

I tried to upload the whole clip unedited but YouTube could not handle the OGG format and conversion.
I ended up using some video editing software (and trimmed it down a bit.) When I tried exporting the final product so that I could upload it to YouTube I was not happy with the file size to quality trade-offs. (Yeah, I am bandwidth limited here in the middle of now where.) I ended up exporting to a couple of different formats and uploaded one of large files (H264, MOV, MPEG4)

I was not completely happy with the experience and decided to do some more research. I discovered (no surprise) that the current flavors of Linux have some powerful utilities assuming that you are willing to work from the command line.

I have a many of the audio and video codecs loaded so I did not actually need to install anything new... your mileage may very.

Here are a couple of examples:
ffmpeg -i fileA.ogg fileA.avi
ffmpeg -i fileA.ogg fileA.mov

The file size and quality were very good. I am sure that with some additional tweaking I could improve upon the results of tonight's exercise.

Take a look at: man ffmpeg for more details