Most likely it's just the emulator being slow. I've found that the Wii tends to use *much* more high quality in-game movies, and that even a good box has trouble keeping up. I'm not sure how Dolphin handles this, I don't know if they play the movie using the game's functions or if they play it using a high level function. If it's the latter case, then the movie decoder in Dolphin needs to be optimized. More likely, you'll just need to wait for the overall speed of the emulator to increase.
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