In that case, video editing softwares and materials should also conceal a private key, in order to trace the origin of manipulation.
The whole chain of video production should be signed in order to trace filming and edition altogether and, all intermediary signatures from each stage of production process contained in a final signature.
That may be a business opportunity or at least (may be preferably) an interresting open source project.
You would need to sign a video with at least four keys: a public key from you, a private key from editor software, a public key from editor software, a public key from editor software generating the previous version of the video. And you would generate signatures for all public-private and private-private pairs and a seal value from a signed hash of those signatures, which is signed by a combination of two public keys in the scheme.
The whole chain of video production should be signed in order to trace filming and edition altogether and, all intermediary signatures from each stage of production process contained in a final signature.
That may be a business opportunity or at least (may be preferably) an interresting open source project.