Have you ever wondered why there is no title or description in your AVI files just like you expect it to be there in your MP3 files? Well AVI does not really support these things. However the Moving Pictures Expert Group has defined the MP4 container format for audiovisual information (which is very much like the MOV container) and did not forget about metadata: They defined a way to put it in there. However as it always comes with standards, where a whole lot of people talk and try to find common ground, there is not one simple way (like ID3), but several complicated ways to choose from. Therefore applications like VLC or Winamp do not support MP4 metadata out of the box. Due to the string relation to the MOV format however iTunes supports MP4 metadata.
Thanks to Markus Waltl I got some links for tools reading and manipulating MP4 metadata. They all have in common that they are rather slow: