Accept "" (nil or null arguments) for tags/annotations

[Former user]

Subtler crashed on me when opening an mp4 with this message:

NSInvalidArgumentException Reason: *** setObjectForKey: object cannot be nil (key: Genre)

I noticed that Subtler strips out all empty tags/annotations when writing out an mp4, but other tools do not. Therefore the assumption that tags/annotations should always have a non-empty string is not valid for all tools.

[Damiano Galassi]

Nil and empty string are not the same value. Do you have a sample file I can use to test?