I think there's always a time when you sit and say yourself: "Oh, I need this video but not in this type", well... fortunately I found a software that could be the solution to this problem. I refer to Any Video Converter, the free version of course because the idea is not to spend money on this, but if you are willing to do so then you can adquire the professional version which price is out of my knowledge.
First at all, you have to installing (ha ha I know, but just in case), once you have the application running (by the way there's an administrator privilege requirement) click on "Add Video" and select the file you want to convert.
After loading the source video, select in "Output Profile" the type of the output video. For this, you can choice the following extensions: mp4, flv, swf, mpg, avi, wmv, asf, mkv, m2ts, mp3, ogg, wav, aac, m4a and wma.
Once you did the selection, there will be a settings panel on the right-bottom corner where you can modify specific parameters that your output file will have. If everythins is ready, go ahead and select "Convert" to start the process.
Perhaps the convert process lasts a no short time (depending on your settings) but once it finishes, the software will display the output file ready to use it.