Video communication apparatus
First Claim
1. A video communication apparatus for video communication between multiple parties, comprising:
- a plurality of first demodulator and decoder units for demodulating and decoding a plurality of input video signals originating from said multiple parties, wherein each of said plurality of first demodulator and decoder units produces a first demodulated video signal including a sequence of fields;
a plurality of video field buffers, each of said plurality of video field buffers storing one of a plurality of first demodulated video signals produced by an associated one of said plurality of first demodulator and decoder units from one of said plurality of input video signals;
a video field selector that generates a single analog output video signal comprising a sequence of fields, wherein said video field selector selects each field within said single analog output video signal from among fields within said plurality of first demodulated video signals stored within said plurality of video field buffers; and
a code generator which adds field identification codes to each field within said single analog output video signal, wherein each field identification code identifies an input video signal from which an associated field was derived; and
a coder and modulator that codes and modulates said single analog output video signal for transmission to said multiple parties.
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Accused Products
Abstract
In a video conference between N parties, each video conferencing terminal produces a respective video signal comprising, in the case of the National Television Standard Committee (NTSC) standard, sixty fields per second. The input video signals are input to an analog multi-point control unit which selects every Nth field from each input video signal and derives therefrom a single output video signal also of sixty fields per second, in which consecutive fields are derived cyclically from each of the N input video signals in turn. The single output video signal is transmitted to each video conferencing terminal, which separates out the fields of the input video signals present in the single output video signal to provide N individual reduced field rate video signals each comprising 60/N fields per second and each having fields derived from a respective one of the input video signals.
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Citations
11 Claims
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1. A video communication apparatus for video communication between multiple parties, comprising:
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a plurality of first demodulator and decoder units for demodulating and decoding a plurality of input video signals originating from said multiple parties, wherein each of said plurality of first demodulator and decoder units produces a first demodulated video signal including a sequence of fields; a plurality of video field buffers, each of said plurality of video field buffers storing one of a plurality of first demodulated video signals produced by an associated one of said plurality of first demodulator and decoder units from one of said plurality of input video signals; a video field selector that generates a single analog output video signal comprising a sequence of fields, wherein said video field selector selects each field within said single analog output video signal from among fields within said plurality of first demodulated video signals stored within said plurality of video field buffers; and a code generator which adds field identification codes to each field within said single analog output video signal, wherein each field identification code identifies an input video signal from which an associated field was derived; and a coder and modulator that codes and modulates said single analog output video signal for transmission to said multiple parties. - View Dependent Claims (3, 4, 5, 6, 7)
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2. A method of video communication between multiple parties, said method comprising:
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demodulating and decoding a plurality of input video signals originating from said multiple parties to produce a plurality of first demodulated video signals that each include a sequence of fields; storing said plurality of first demodulated video signals; producing a single analog output video signal comprising a sequence of fields, said sequence of fields being selected from among fields within said plurality of first demodulated video signals in a selectively determined order; adding field identification codes to each field within said single analog output video signal, wherein each field identification code identifies an input video signal from which an associated field was derived; coding and modulating said single analog output video signal; and transmitting said single analog output video signal to said multiple parties. - View Dependent Claims (8, 9, 10, 11)
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Specification