I had taken a bunch of videos using my Nokia 800 and they were all great. Unfortunately, once I downloaded them to my computer, I realized I took them all while holding the phone upside down! And in my quest for free software that could rotate a MP4 video file, I downloaded quite a few tools and most of them turned up short and were filled with crap load of crapware!
Finally I came across “Freemake Video Convertor”. Now, even this software came with a bunch of software that it wanted to install on my computer. But they at least give you an option to opt out. Also, you can donate to their company if you end up using their software and like it.
You can download Freemake Video Convertor from: http://www.freemake.com/downloads/
Some other nice features of this software:
Convert videos from a variety of formats to a variety of formats (output: Avi, MP4, Wmv, Dvd, etc).
Also, the software makes it easy to replicate the quality settings of the input file.
You can also crop the video.