I really don’t know why but some of Mp4 format video songs are not playing on my Sony Ericson mobile and displaying the error message unsupported format. I had checked those songs format on my computer and they all are of Mp4 format and my Sony Ericson phone support Mp4 format video. I had also checked for the virus on my Sony Ericson mobile but there was no virus found and I am really confused what should I need to do? I don’t want to restore my phone to factory mode because my all data and installed software will be lost.