Group-of-block based video signal combining for multipoint continuous presence video conferencing
First Claim
1. A method of combining a plurality of video signals in a continuous presence video conferencing system, comprising the steps of:
- receiving an input frame of a video signal from each of a plurality of system users, wherein each of the input frames includes a number of groups-of-blocks (GOBs); and
forming an output frame including at least one of the GOBs from the input frame of each of the plurality of users and less than all of the GOBs from the input frame of at least one of said users.
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Abstract
An apparatus and method for combining video signals from multiple users in a continuous presence video conferencing system. Video signals are received from each of a number of different system users. The signals include input frames each having a number of different groups-of-blocks (GOBs). The GOBs correspond to hierarchically organized video data and header information. The input frame GOBs are used to form a composite output video signal suitable for transmission to each of the system users. An output frame of the composite output signal incorporates at least one of the GOBs from the input frames of each of the users and less than all of the GOBs from the input frame of at least one of the users. The resulting output video signal provides flexible continuous presence video conferencing in which video signals from multiple users may be simultaneously displayed to all users in a selected divided-screen format. The input frames may be Quarter Common Intermediate Format (QCIF) frames and the output frames may be Common Intermediate Format (CIF) frames in accordance with the H.261 video coding standard.
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Citations
20 Claims
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1. A method of combining a plurality of video signals in a continuous presence video conferencing system, comprising the steps of:
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receiving an input frame of a video signal from each of a plurality of system users, wherein each of the input frames includes a number of groups-of-blocks (GOBs); and forming an output frame including at least one of the GOBs from the input frame of each of the plurality of users and less than all of the GOBs from the input frame of at least one of said users. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A coded-domain video signal combiner for use in a continuous presence video conferencing system, comprising:
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a plurality of input buffers adapted to receive an input frame of a video signal from each of a corresponding plurality of system users, wherein each of the input frames includes a number of groups-of-blocks (GOBs); and a multiplexer coupled to said plurality of input buffers and operative to form an output frame including at least one of the GOBs from the input frame of each of the plurality of users and less than all of the GOBs from the input frame of at least one of said users. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification