Video switching system
First Claim
1. A switching system for video signals comprising:
- A. a plurality of inputs for receiving a corresponding plurality of input video signals, including a current video signal;
B. a preview output and a program output, said preview output being adapted for connection to a preview video monitor;
C. preview selection means for selecting one of a plurality of inputs and for placing the input video signal associated with the selected input onto a preview bus, said preview bus carrying the selected signal to said preview output;
D. program connection means for connecting the input associated with the current video signal to a program bus;
E. a take switch;
F. take control means including a first input connected to said preview bus, a second input connected to said program bus, an output connected to said program output, said take control means generating an output video signal corresponding to the video signal on the program bus prior to activation of said take switch, and, after activation of the take switch, generating an output video signal corresponding to the video signal on the preview bus, the program connection means being responsive to said take control means to connect the input associated with the preview bus video signal to the program bus, the take control means thereafter generating an output signal corresponding to the program bus video signal.
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Abstract
A video switching system particularly adapted for use in a small studio environment includes a group of independent selection switches that enables a user to select any one of a plurality of different input video signals and route that signal to a preview output for display on a preview monitor. When it is desired to switch the previewed signal to a program output for actual broadcasting, the user activates a take switch. The system, however, does not abruptly switch the previewed signal to the program output, but rather automatically generates a mixture of the previewed signal and old program signal and automatically adjusts the mixture so that the old program signal is uniformly faded out and the previewed signal is uniformly faded into the program scene. The effect of the transition to the previewed signal is thereby automatically softened. The rate at which the transition takes place is broadly adjustable and may be selected so that it is accomplished in a period of time anywhere from that corresponding to a few video frames up to that corresponding to several hundred video frames. When the previewed signal is completely faded into the program scene, the system invisibly switches the previewed signal directly to the program output, thereby automatically enabling the user to select other video signals for previewing in preparation for future program changes. The system is such that a particular input signal can be switched to the program only if that signal is first selected for previewing by activation of one of the preview selection switches. The user is thereby forced to preview all scenes prior to presenting them to the program.
33 Citations
20 Claims
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1. A switching system for video signals comprising:
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A. a plurality of inputs for receiving a corresponding plurality of input video signals, including a current video signal; B. a preview output and a program output, said preview output being adapted for connection to a preview video monitor; C. preview selection means for selecting one of a plurality of inputs and for placing the input video signal associated with the selected input onto a preview bus, said preview bus carrying the selected signal to said preview output; D. program connection means for connecting the input associated with the current video signal to a program bus; E. a take switch; F. take control means including a first input connected to said preview bus, a second input connected to said program bus, an output connected to said program output, said take control means generating an output video signal corresponding to the video signal on the program bus prior to activation of said take switch, and, after activation of the take switch, generating an output video signal corresponding to the video signal on the preview bus, the program connection means being responsive to said take control means to connect the input associated with the preview bus video signal to the program bus, the take control means thereafter generating an output signal corresponding to the program bus video signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A switching system for video signals comprising:
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A. a plurality of inputs for receiving a corresponding plurality of input video signals, including a current video signal; B. a preview output and a program output, said preview output being adapted for connection to a preview video monitor; C. preview selection means for selecting one of a plurality of inputs and for placing the input video signal associated with the selected input onto a preview bus, said preview bus carrying the selected signal to said preview output; D. program connection means for connecting the input associated with the current video signal to a program bus; E. a take switch; F. take means including; i. first means including a first input connected to said preview bus, a second input connected to said program bus, and an output connected to said program output, and ii. second means responsive to actuation of said take switch for generating take signal; said first means including means for generating an output video signal that is the input video signal on the program bus prior to actuation of said take switch, and after actuation of the take switch, is responsive to said take signal for generating a mixture of the input signal on the preview bus and the input signal on the program bus and for varying the output signal such that the level of the preview bus input signal is increased while the level of the program bus input signal is decreased to effect a gradual transition of the preview bus input signal to the program output. - View Dependent Claims (18, 19, 20)
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Specification