Particular viewers might find war violence or medieval violence more acceptable than sexual violence. Others might feel the opposite way. Some will want to avoid any severe violence. Such a system could respond to viewer's in several ways. You see and hear what you want, I see and hear what I want.
Audio substitution is quite easy to do with technology now available.
Substituting video is more complex for TV broadcast transmissions because of their limited bandwidth. In the future, when digital TV is widely distributed, substituting video will become relatively easy. The standards and technologies developed for television are likely to affect other media as well. Both audio and video substitution are within the capability of video disks, CDs, and ROM memory. They can store original and substitute video and audio, and present the appropriate version based on the user's setting of a control on the playback device.