My many friends asked me about how to change the video formats ? and i used to recommend format factory and the best thing about the format factory is its free !! you don't have to buy the video converter to convert the videos !!
You can convert the videos in the many formats using the format factory like mp4, avi, 3gp, GIF, WMV, MKV and many more formats and all you have to do is just download the format factory and install it and open it and from the left side bar just choose the format you want to convert your video like all to mobile device etc. and then add the videos and the format factory allows us to add more videos to convert simultaneously so it will save the time too !!
Get the format factory from here ;)
The another best thing about the format factory is that you can customize the sizes of the video too !! (i.e. width and height) so you can also convert the video for any device by changing the sizes of the video.
Not just videos using the format factory we can change the formats of audio, picture and cd/dvd. all you have to do is to just select the format in which you want to convert the video and one windows will popup and browse your video file and hit ok and then click on start ;) it will take time and when the video is converted in the selected format then it will notify you. and for the other files you can convert it using the same method as we have discussed about converting the videos in the other formats !! and you can easily access the converted files by just opening the output folder.
If you have any question then feel free to ask ;)