How is a NFT Token ID assigned to an object (e.g., picture, tweet, video, etc.)

Question

Background: Suppose I want to verify the ownership of some tweet or some picture by looking up the data in the blockchain. If my understanding is correct, I need to be able to assign a unique tokenId that represents that tweet/picture.

Question 1: Is there some standardization on how this ID is assigned? Do different platform perform this mapping in a unique way? I feel like without such a standardization, the non-fungibility becomes questionable (e.g., do you really own this tweet, or do you only own it if you apply the tweet->token ID mapping you crafted yourself?).

Question 2: Could you provide a few examples of how exactly is the token ID assigned to some (well-known) NFTs?

Answer 1

When an NFT is minted with a smart contract, associated with the NFT TokenID, the block chain also typically records a URI (universal resource identifier) that points to the NFT metadata (usually a json file). This URI can be obtained by querying the blockchain via the smart contract address and TokenID. The json file itself includes, among other things, another URI that points to the digital asset linked with the NFT. If immutable URIs are used (e.g. IPFS URIs), the URI recorded in the block chain for the NFT TokenID is unambiguously linked to the unchangeable json file which unambiguously links to the unchangeable digital asset. As Petr correctly points out, technologically, nothing prevents anyone else from minting another NFT that also records the same URI and therefore points to the same json file (and by transitivity to the same digital asset). I've tried to be precise in the preceding statements to avoid incorrect extrapolatory claims that would actually depend on the smart contract implementation details.