SUPER video encoder is a pretty handy UI for ffmpeg and mencoder processing, however, keep in mind this tool will create temp files on your hard disk during the encoding process.
Normally this is not an issue, as the temp files are deleted after processing is complete, however, if there are failures during processing or if you cancel the process, temp files may be leftover on your hard disk even if you were encoding to an external drive.
In the screenshot below, I encountered a 30gb video file during my travels which I had a tough time finding the right encoding method for that didn’t take too long. Cancelling the process twice caused a situation illustrated by the screenshot below:
Deleting the temp files is no problem of course, and to navigate to the appropriate directory simply open an explorer window and type %TEMP% in the Window path.