| 摘要 |
A video mixing apparatus for mixing a first video signal and a second video signal in accordance with a first key signal and a second key signal. The video mixing apparatus includes a key signal mixer for receiving the first and second key signals and generating and outputting a third key signal and a fourth key signal, wherein a level K1 of the first key signal, a level K2 of the second key signal, a level Kp of the third key signal, and a level Km of the fourth key signal satisfy the relationships:Kp=K2-K1K2, andKm=K1+K2-K1K2;a key signal division section for receiving the third and fourth key signals and generating and outputting a fifth key signal, wherein a level Kg of the fifth key signal satisfies the relationship:Kg=Kp/Km; and a first video signal mixer for receiving the first and second video signals and the fifth key signal and generating and outputting a third video signal by mixing the first and second video signals at a mix ratio which is in accordance with the fifth key signal.
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