Part of the hearing aspect is that our voices sound deeper to us when we're speaking than they do in recordings, because we hear it not only through the air but through our own skulls, and lower-frequency sounds travels through mediums better than higher-frequency ones, and also the sound resonates in certain cavities within the skull. I don't know about video, except that obviously when we look in mirrors we only see ourselves head-on. And we don't normally see our own mannerisms and such. Maybe we interpret our own mannerisms uncharitably due to poor self-image.