| 摘要 |
Method and apparatus for combining a first video signal and a second video signal. The method comprising the act of replacing data in the second video signal with corresponding, in respect of a position within an image, data from the first video signal when said data in the second video signal represent a predefined repetitive pattern. The apparatus comprising a first input for input of the first video signal; a second input for input of the second video signal; an output for output of a third video signal; a keying-pattern detector connected to said second input for detecting a predefined repetitive pattern, wherein said keying-pattern detector comprises a means for receiving and/or storing a representation of the predefined repetitive pattern, and an output that is arranged to provide a signal indicating whether said predefined repetitive pattern is detected or not; and a video switch connected to said first input, said second input, said output and said output of the keying-pattern detector for continuously selecting a video signal from one of the first and second input to be represented in a third video signal, said selection being controlled by a signal from the output of the keying-pattern detector. |
