Device, method and system for variable bit-rate packet video communications

A transcoding device at an entry node in a packet-based communication system for utilizing conversion of a constant bit-rate (CBR) multimedia bitstream to a corresponding variable bit-rate multimedia bitstream for efficient transmission of the bitstream, comprising:

• A) a demultiplexer, operably coupled to receive a CBR multimedia bitstream, for demultiplexing said bitstream to provide constant bit-rate bitstreams that correspond to component media in the multimedia bitstream,
• B) a plurality of transmitting processors, operably coupled to the demultiplexer, each for processing a component constant bit-rate bitstream to provide a corresponding variable bit-rate component bitstream, packetizing said bitstream and transmitting said packetized bitstream over a packet network, wherein said entry node is an element of a communication system that further includes a transmitting terminal for generating the constant bit-rate (CBR) multimedia bitstream, an exit node for receiving the packetized bitstreams, and a receiving terminal operably coupled to the exit node, wherein the exit node comprises:
• C) a plurality of receiving processors, each for receiving and processing a component variable bit-rate packetized bitstream to provide a corresponding constant bit-rate component bitstream, and
• D) a multiplexer, operably coupled to the plurality of receiving processors, for multiplexing the constant bit-rate component bitstreams and providing the multiplexed bitstream to the receiving terminal,
• wherein the component variable bit-rate packetized bitstreams include a variable bitrate video packetized bitstream, a variable bit-rate audio packetized bitstream, and, where selected, a variable bit-rate data packetized bitstream.

A transcoding device at an entry node in a packet-based communication system for utilizing conversion of a constant bit-rate (CBR) multimedia bitstream to a corresponding variable bit-rate multimedia bitstream for efficient transmission of the bitstream, comprising:

• A) a demultiplexer, operably coupled to receive a CBR multimedia bitstream, for demultiplexing said bitstream to provide constant bit-rate bitstreams that correspond to component media in the multimedia bitstream,
• B) a plurality of transmitting processors, operably coupled to the demultiplexer, each for processing a component constant bit-rate bitstream to provide a corresponding variable bit-rate component bitstream, packetizing said bitstream and transmitting said packetized bitstream over a packet network, wherein said entry node is an element of a communication system that further includes a transmitting terminal for generating the constant bit-rate (CBR) multimedia bitstream, an exit node for receiving the packetized bitstreams, and a receiving terminal operably coupled to the exit node, wherein the exit node comprises:
• C) a plurality of receiving processors, each for receiving and processing a component variable bit-rate packetized bitstream to provide a corresponding constant bit-rate component bitstream, and
• D) a multiplexer, operably coupled to the plurality of receiving processors, for multiplexing the constant bit-rate component bitstreams and providing the multiplexed bitstream to the receiving terminal,
• wherein the transmitting video processor comprises:
• E) a transcoder, operably coupled to receive a constant bit rate H.261 video bitstream, for converting said bitstream to a variable bit-rate H.261 bitstream with a reduced average bit-rate,
• F) a video packetizer, operably coupled to the transcoder, for packetizing the variable bit-rate H.261 bitstream, assigning a priority in accordance with a predetermined prioritization scheme and then transmitting the packetized bitstream to a packet network, and
• G) a traffic shaper, operably coupled to the video packetizer and coupled to transmit a quantization parameter to the transcoder, for providing a quantization parameter to the transcoder,
• wherein the traffic shaper determines the quantization parameter for the transcoder utilizing one of:
• 1) statistical information about a packet sequence from the video packet output from the video packetizer, and
• 2) packet network feedback congestion information, and wherein the transcoder adjusts a transcoder output bit-rate according to a predetermined transcoding scheme.

A method in a packet network-based transcoding entry node for a communication system for utilizing conversion of a constant bit-rate multimedia bitstream to a corresponding variable bit-rate multimedia bitstream for efficient transmission of bitstream, comprising the steps of:

• A) demultiplexing, by a demultiplexer, the CBR multimedia bitstream to provide constant bit-rate component bitstreams that correspond component media in the multimedia bitstream,
• B) processing, by a plurality of transmitting processors, each component constant bit-rate bitstream to provide a corresponding variable bit-rate component bitstream, packetizing said bitstream, and transmitting said packetized bitstreams over a channel of at least a first packet network, wherein said entry node is an element of a communication system that further includes a transmitting terminal for generating the constant bit-rate multimedia bitstream, an exit node for receiving the packetized bitstreams, and a receiving terminal operably coupled to the exit node, further including the steps, at the exit node, of:
• C) receiving and processing, by a plurality of receiving processors, each component variable bit-rate packetized bitstream to provide a corresponding constant bit-rate component bitstream, and
• D) multiplexing, by a multiplexer, the constant bit-rate component bitstreams and providing the multiplexed bitstreams to the receiving terminal,
• wherein the component variable bit-rate packetized bitstreams include a variable bit-rate video packetized bitstream, a variable bit-rate audio packetized bitstream, and, where selected, a variable bit-rate data packetized bitstream.

A method in a packet network-based transcoding entry node for a communication system for utilizing conversion of a constant bit-rate multimedia bitstream to a corresponding variable bit-rate multimedia bitstream for efficient transmission of bitstream, comprising the steps of:

• A) demultiplexing, by a demultiplexer, the CBR multimedia bitstream to provide constant bit-rate component bitstreams that correspond component media in the multimedia bitstream,
• B) processing, by a plurality of transmitting processors, each component constant bit-rate bitstream to provide a corresponding variable bit-rate component bitstream, packetizing said bitstreams and transmitting said packetized bitstreams over a channel of at least a first packet network, wherein the constant bit-rate multimedia bitstream includes constant bit-rate video and audio bitstreams and, where selected, a constant bit-rate data bitstream, further including the steps of:
• C) transcoding, by a transmitting (Tx) video processor, the constant bit-rate video bitstream into a modified variable bit-rate video bitstream in accordance with a predetermined bit syntax, packetizing the modified variable bit-rate video bitstream into variable bit-rate video packets and sending the variable bit-rate video packets over a channel of at least a first packet network,
• D) transcoding, by a transmitting (Tx) audio processor, the constant bit-rate audio bitstream into a variable bit-rate audio bitstream in accordance with a predetermined audio coding technique, packetizing the processed audio bitstream, and sending the packetized processed audio bitstream over a second channel of at least a first packet network, and
• E) where selected, processing, by a transmitting data processor, the constant bit-rate data bitstream into a variable bit-rate data bitstream in accordance with a predetermined data coding technique, packetizing the processed data bitstream, and sending the packetized data bitstream over a third channel of at least a first packet network,
• wherein the steps implemented by the transmitting video processor include the steps of:
• F) converting, by a transcoder, a constant bit rate H.261 bitstream to a variable bit-rate H.261 bitstream with a reduced average bit-rate,
• G) packetizing, by a video packetizer, the variable bit-rate H.261 bitstream, assigning a priority in accordance with a predetermined priority scheme and then transmitting the packetized bitstream to a packet network, and
• H) utilizing a traffic shaper, operably coupled to the video packetizer and coupled to transmit a quantization parameter to the transcoder, for providing a quantization parameter to the transcoder,
• wherein the traffic shaper determines the quantization parameter for transmission to the transcoder utilizing one of:
• 1) statistical information about a packet sequence from the video packet output from the video packetizer, and
• 2) packet network feedback congestion information, and wherein the transcoder adjusts a transcoder output bit-rate according to a predetermined transcoding scheme.