I have experimented with this program in order to test the option of converting MP4 files to the AVI container for use with VirtualDUB. When I tried to convert an MP4 video to the AVI container using this program I found that after the conversion the sound was badly distorted using both the 'Source Audio' and the 'LAME MP3 Best Quality' settings. However, when performing the same operation using ffmpeg from the command line I had no problem with audio and the picture appeared to be undistorted. Here is the command that I used: ffmpeg -i "[input]" -flags +global_header -vcodec copy -acodec copy "[output]" The version of ffmpeg that I used was: ffmpeg-20160227-git-5156578-win32-static Considering that this program is just a frontend for ffmpeg it ought to be able to handle sound competently. I suggest that the author re-writes this program to use ffmpeg on the users system, but this is unlikely to happen because I am sure that he has long since lost interest in it.