Video transmission rate matching for multimedia communication systems

Claim 2

A bit stream rate matching apparatus as set forth in Claim 1 characterized in that each of the plurality of incoming video bit streams is from a corresponding endpoint device, and each of the plurality of outgoing video bit streams is directed to a corresponding endpoint device, specific ones of the incoming video bit streams being associated with specific ones of the outgoing video bit streams to form an associated incoming-outgoing video bit stream, each associated incoming-outgoing video bit stream corresponding to a particular endpoint device.

Claim 3

A bit stream rate matching apparatus as set forth in Claim 1 further comprising processor means 840, coupled to the first and second switching means, bit rate increasing means, and bit rate reduction means, for controlling the first and second switching means.

Claim 4

A bit stream rate matching apparatus as set forth in Claim 2 further characterized by processor means, coupled to the first and second switching means for controlling the first and second switching means.

Claim 5

A bit stream rate matching device characterized by (a) bit rate increasing means for converting a video bit stream having a first transmission rate to a video bit stream having a second transmission rate, wherein the first transmission rate is less than the second transmission rate, and; (b) bit rate reducing means for converting a video bit stream having the second transmission rate to a video bit stream having the first transmission rate.

Claim 6

A video bit stream rate matching device for use in a system characterized by: a first endpoint device characterized by video transceiver means for transmitting and receiving a video bit stream having a first transmission rate, and a second endpoint device characterized by video transceiver means for transmitting and receiving a video bit stream having a second transmission rate, wherein the second transmission rate differs from the first transmission rate; the video bit stream rate matching device being coupled to the first and second endpoint devices; CHARACTERIZED IN THAT the video bit stream rate matching device includes rate conversion means for converting a video bit stream having a first transmission rate to a video bit stream having a second transmission rate, and for converting a video bit stream having a second transmission rate to a video bit stream having a first transmission rate.

Claim 7

The video bit stream rate matching device of Claim 1, further characterized by: (a) video multiplex decoder means for decoding and demultiplexing an input video bit stream having a first transmission rate; the video multiplex decoder having a first output adapted to generate quantized information in the form of quantized discretet cosine transformation coefficients in response to the input video bit stream; the video multiplex decoder means having a second output adapted to generate motion vectors in response to the input video bit stream; (b) video multiplex encoder means for encoding and multiplexing quantized discrete cosine transformation coefficients with motion vectors to generate an output video bit stream; the video multiplex encoder means having a first input adapted to receive quantized direct cosine transformation coefficients, a second input adapted to receive motion vectors, and an output adapted to generate the output video bit stream; (c) discrete cosine transformation coefficients processor means for processing a plurality of quantized discrete cosine transformation coefficients generated from a decoded, demultiplexed video bit stream having N bits, the processor processing the quantized discrete cosine transformation coefficient such that, after processing, the quantized discrete cosine transformation coefficients provide an encoded. multiplexed video bit stream having M bits, wherein M≠N; the discrete cosine transformation coefficients processor means having a rate control input for specifying a desired bit rate for the encoded, multiplexed video bit stream; and (d) rate control means for controlling the bit rate of the encoded, multiplexed video bit stream, the rate control means having: (i) a first communications port for receiving a desired bit rate, and adapted for coupling to an endpoint device; (ii) a second communications port for receiving a video bit stream having a transmission rate R; and (iii) an output port for generating a video bit stream transmission rate S¹ in response to the receipt of transmission rates at the first and second communications ports; characterized in that the first output of the video multiplex decoder means is coupled to the direct cosine transformation coefficients processor means, the second output of the video multiplex decoder means is coupled to the second input of the video multiplex encoder means, the output of the video multiplex encoder means is coupled to the second communications port of the rate control means, and the output port of the rate control means is coupled to the rate control input of the direct cosine transformation coefficients processor.

Claim 8

A digital video transmission rate matching system characterized by: a first switching means having N input ports, first, second, and third output ports, and a control signal input port; the control signal port being adapted to receive a plurality of control signals, each control signal specifying a particular set of connections between the N input ports and any of the first, second and third output ports; the first switching means, in response to the receipt of any one of the plurality of control signals, connecting the N input ports to any of the first, second, and third output ports as specified by the any one of the plurality of control signals; a second switching means having first, second, and third input ports, N output ports and a control signal input port; the control signal input port being adapted to receive a plurality of control signals, each control signal specifying a particular set of connections between any of the first, second, and third input ports and the N output ports; the second switching means, in response to the receipt of any one of the plurality of control signals, connecting the N output ports to any of the first, second and third input ports as specified by the any one of the plurality of control signals; a transmission rate reduction means having an input adapted to receive a video bit stream of bit rate R bits per second, an output adapted to transmit a video bit stream of bit rate S¹ bits per second, wherein R is greater than S¹, and video bit stream compression means for transforming a video bit stream of bit rate R bits per second to a video bit stream of bit rate S bits per second; a transmission rate increasing means having an input adapted to receive a video bit stream of bit rate S bits per second, an output adapted to transmit a video bit stream of bit rate R bits per second, wherein R is greater than S, and video bit stream expansion means for transforming a video bit stream of bit rate S bits per second to a video bit stream of bit rate R bits per second; characterized in that the first output port of the first switching means is coupled to the input of the transmission rate reduction means, the second output port of the first switching means is coupled to the input of the transmission rate increasing means, the third output port of the first switching means is coupled to the third input port of the second switching means; the first input port of the second switching means is coupled to the output of the transmission rate reduction means; the second input port of the second switching means is coupled to the output of the transmission rate increasing means; the N input ports of the first switching means are each adapted to receive an incoming video bit stream and the N output ports of the second switching means are each adapted to transmit an outgoing video bit stream.

Claim 9

The digital video transmission rate matching system of Claim 4 characterized in that the transmission rate reduction means is the video bit stream rate matching device of Claim 1, 2 or 3.

Claim 10

The digital video transmission rate matching system of Claim 4, 5, 6 or 7 characterized in that the transmission rate increasing means is a bit stuffing device.

Claim 12

A method of providing video bit stream rate matching as set forth in Claim 11, characterized in that the DCT coefficients include a first subset of DCT coefficients corresponding to low-frequency video information and a second subset of DCT coefficients corresponding to high-frequency video information, the step of discarding being performed by discarding the second subset of DCT coefficients.

Claim 13

A method of providing video bit stream rate matching as set forth in Claim 12 characterized in that the high-frequency video information corresponds to video information above approximately 4.5 mHz.