Method and apparatus for displaying two video pictures simultaneously
First Claim
1. A method for displaying video pictures of a first and a second received video signal comprising the steps of:
- storing the first received video signal in a first memory at a first predetermined frequency in synchronism with a synchronizing signal of the first received video signal;
storing the second received video signal in a second memory at said first predetermined frequency in synchronism with a synchronizing signal of the second received video signal;
reading out the first and second received video signals alternately linewise from the first and second memories at a second predetermined frequency in synchronism with the synchronizing signal of either the first received video signal or the second received video signal; and
displaying the video pictures corresponding to the first and second received video signals on a video screen.
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Abstract
A method and an apparatus for simultaneously displaying two independent video signals are described. The apparatus comprises video signal input terminals (2, 6) for receiving first and second video signals in PAL system having the field frequency of 50 Hz, Y/C processors (7, 8) connected to the video signal input terminals (2, 6), A/D converters 16, 24) connected to the Y/C processors two port field memories 17, 22) having a random block addressing mode for storing the digital Y/U/V signals from the A/D converters, a D/A converter (19) connected to an output of the field memories 17, 22) and deriving analog Y/U/V signals which are converted to R/G/B signals and supplied to a display (10), a write and read control signal generator (14; 20, 21) for generating first and second write control signals so that the first and second digital Y/U/Y signals are written into the first and second field memories (17, 22) at a first predetermined frequency in synchronisms with the synchronizing signals of the first and second video signals, respectively, and for generating first and second read control signals so that the first and second digital Y/U/V signals are alternately linewise read-out from the first and second field memories 17, 22) at four times the first predetermined frequency in synchronism with a master synchronizing signal of either the first or second video signals and which are displayed each in an aspect ratio of 4:3 or 3:3 on the screen having a wide aspect ratio of 16:9 in a 100 Hz flickerless mode.
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Citations
11 Claims
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1. A method for displaying video pictures of a first and a second received video signal comprising the steps of:
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storing the first received video signal in a first memory at a first predetermined frequency in synchronism with a synchronizing signal of the first received video signal; storing the second received video signal in a second memory at said first predetermined frequency in synchronism with a synchronizing signal of the second received video signal; reading out the first and second received video signals alternately linewise from the first and second memories at a second predetermined frequency in synchronism with the synchronizing signal of either the first received video signal or the second received video signal; and displaying the video pictures corresponding to the first and second received video signals on a video screen.
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2. A video display apparatus comprising:
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video signal input terminal means for receiving first and second video signals; first memory means for storing the first video signal; second memory means for storing the second video signal; write and read control signal generating means for generating; a first write control signal controlling the first memory means so that the first video signal is written into said first memory means at a first predetermined frequency in synchronism with a synchronizing signal of the first video signal; a second write control signal controlling the second memory means so that the second video signal is written into said second memory means at the first predetermined frequency in synchronism with a synchronizing signal of the second video signal; and read clock signals controlling said first and second memory means so that the first and second video signals are alternatively linewise read out from said first and second memory means at a second predetermined frequency in synchronism with the synchronizing signal of either the first video signal or the second video signal; and display means provided with the first and second video signals read out from said first and second memory means for displaying two pictures corresponding to the first and second video signals on a screen thereof. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification