I'm trying to remember the name of this animated movie ( it may be full length or short)

The only thing I can remember is there is a princess who falls in love with a man and there's an evil emperor with this red ruby. With the ruby he turns the princess into a crane. Somehow the man she falls for also turns into a crane and the ruby breaks leaving them to be cranes forever and the fly off together at the end. Now when I describe this movie to people they tell me its the swan princess but I know it's NOT! It has been driving me crazy that I can't find it anywhere. Can you help me???

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