@Anna Johnson, I am using Nokia 2700c mobile phone. When I was using "Free Studio 5.1.5" then there was no problem in the conversion of videos into MP4 format. But in the latest version, when I convert any video file into MP4 format by "Free 3gp Video Converter" in "Free Studio 5.1.7" then the converted video doesn't play in my phone only sound comes. This problem was also occurring in the old version of "Free Studio 5.0.X something".
@Alice, Yes, I have tried High Quality MP4 but still this problem is occurring. I used to convert videos for my mobile by High Quality MP4 320x240 with the old version of Free Studio and it was very good, but from the time I have installed this new version i.e. Free Studio 5.1.7, only sound comes not the video in my mobile phone. Please resolve this problem.