1. For each decoder, there is a code stream that makes it unable to work.
2. The code stream is equivalent to an optical disc, and the video codec is equivalent to a player. From a mathematical point of view, they are homogeneous devices. This is a new interpretation.
3. The meaning of coding and implication. There is a view that the difference between a coded message and an uncoded message is that the former cannot represent anything by itself, and knowledge about coding is required. Gödel’s number can refute this view. In fact, there are no uncoded messages in reality. There are only messages compiled with more familiar codes and messages compiled with less familiar codes. If you want to reveal The meaning of a message must be extracted from the compiled code by some mechanism or isomorphic method. It may be difficult to find the way to decode it, but once it is discovered, the information will be as clear as water. When encoding and decoding are familiar enough, it doesn't look like encoding, so people forget that there is a decoding mechanism, so that the message is completely equivalent to its meaning.