Reducing loss in transmission quality under changing network conditions

Abstract

An apparatus for dynamically controlling the delivery of data over a network is provided. The apparatus includes a network interface circuit with at least one communication port adapted to be coupled to a network. The apparatus further includes an encoder that is communicatively coupled to the network interface circuit. The encoder is adapted to receive data from a source and to encode the data with a selectable level of compression. The network interface circuit includes a control mechanism that provides a signal to select the level of compression for the encoder based on at least one parameter.

1 . A method for controlling delivery of video over an asynchronous transfer mode (ATM) network, the method comprising: 
 establishing a first encoding level for a video encoder;    receiving video data from at least one video source;    encoding the video data with the first encoding level;    transmitting the encoded video data over a plurality of communication lines to the ATM network via an inverse multiplexer; and    when at least one of the plurality of communication lines becomes unusable, modifying the encoding level to encode with a second, different rate.    
   
   
       2 . The method of  claim 1 , wherein establishing a first encoding level comprises establishing a data rate for an MPEG encoder.  
   
   
       3 . The method of  claim 1 , wherein receiving video data comprises receiving video data from a plurality of video sources.  
   
   
       4 . The method of  claim 1 , wherein transmitting the encoded video data over a plurality of communication lines comprises transmitting the encoded video data over a plurality of T1 or E1 lines.  
   
   
       5 . The method of  claim 1 , wherein modifying the encoding level comprises reducing the data rate.  
   
   
       6 . The method of  claim 5 , and further comprising: 
 when at least one of the plurality of connections becomes unusable: 
 calculating an available bandwidth for delivering the video data; and  
 establishing a second, different data rate for a video encoder used to deliver the video data based on the currently available bandwidth.  
   
   
   
       7 . An access device, comprising: 
 an inverse multiplexer having a plurality of network ports adapted to couple to a plurality of communication lines for an asynchronous transfer mode (ATM) network;    an encoder, communicatively coupled to the inverse multiplexer, that is adapted to receive data from at least one audio/video source;    a control mechanism, communicatively coupled with the inverse multiplexer and the encoder, the control mechanism producing at least one control signal to control the rate of the encoder based on a condition of the ATM network; and    wherein the encoder, the control mechanism, and the inverse multiplexer are located in a common housing.    
   
   
       8 . The access device of  claim 7 , wherein the inverse multiplexer includes a data port adapted to couple to at least one data source, and at least one telephony port adapted to couple to at least one telephony line.  
   
   
       9 . The access device of  claim 7 , wherein the encoder and the control mechanism are communicatively coupled over a bus.  
   
   
       10 . The access device of  claim 7 , wherein the encoder comprises an MPEG encoder.  
   
   
       11 . The access device of  claim 7 , wherein the control mechanism reduces the rate of the encoder when one of the plurality of connections to the ATM network is unusable.  
   
   
       12 . An apparatus for dynamically controlling the delivery of data over a network, the apparatus comprising: 
 a network interface circuit with at least one communication port adapted to be coupled to a network;    an encoder, communicatively coupled to the network interface circuit, the encoder adapted to receive data from a source and to encode the data with a selectable level of compression; and    wherein the network interface circuit includes a control mechanism that provides a signal to select the level of compression for the encoder based on one parameter;    wherein the network interface circuit comprises an inverse multiplexer (IMUX) with a plurality of network ports, each network port adapted to be coupled to a selected communication link of the network.    
   
   
       13 . The apparatus of  claim 12 , wherein the encoder is adapted to receive data from at least one of a video source, and an audio source.  
   
   
       14 . The apparatus of  claim 12 , wherein the network interface circuit further is adapted to receive at least one of high-speed data and telephony data.  
   
   
       15 . The apparatus of  claim 12 , wherein the encoder comprises an encoder that is adapted to receive input from a plurality of data sources.  
   
   
       16 . The apparatus of  claim 12 , wherein each port is adapted to be coupled to at least one of a T1 and an E1 communication link.  
   
   
       17 . The apparatus of  claim 12 , and further comprising a bus, communicatively coupling the network interface circuit and the encoder, the bus being adapted to carry commands from the control mechanism of the network interface circuit to the encoder.  
   
   
       18 . The apparatus of  claim 12 , wherein the control mechanism generates signals to control the rate of the encoder based on at least one of available bandwidth, buffer levels and signals over an end-to-end channel of the network.