I find a distinctive video converter software, share with everyone .DDVideo 3GP video converter gain,it can gain the vlolume of video file to the same volume without loss of sound quality.default is 89db(the sound too loud,our hearing will be hurt),with this software,watch video and listen to the sound never again worry about varying volume and manually adjust the Volume Level (VOL +/-).
I have using the software now,I feel well.

You might also try it.
we can discuss it together.

See More: enjoy video with mobile phone,we must care our hearing