Real Time Bit Rate Switching for Internet Protocol Television

Abstract

A method, apparatus and computer program product are provided for delivering television programming to a subscriber. In one aspect the method includes receiving one or more channels of program content, and encoding each channel a plurality of times, each time at a different rate producing multiple rate encoded signals for each channel. The method can further include transmitting the multiple rate encoded signals to a central office over a network, determining an available bandwidth of a downstream link to a subscriber and a current bit rate available for transmission to the subscriber. The method can further include selecting a best available bit rate from the multiple rate encoded signals for a requested channel and transmitting the selected rate encoded signal to the subscriber.

1 . A method comprising:
 receiving, at a centralized server, a plurality of encoded signals generated from one or more input signals;   determining, at the centralized server, one or more transmission characteristics associated with a subscriber;   identifying, at the centralized server, a channel with a highest available bit rate from the plurality of encoded signals based on the one or more transmission characteristics; and   transmitting the channel with the highest available bit rate to the subscriber.   
     
     
         2 . The method of  claim 1 , where determining the one or more transmission characteristics includes determining one or more transmission characteristics associated with a transmission link coupled between the centralized server and the subscriber. 
     
     
         3 . The method of  claim 1 , where receiving the plurality of encoded signals includes receiving the plurality of encoded signals generated from encoding the one or more input signals a plurality of times, each time at a different rate. 
     
     
         4 . The method of  claim 1 , further comprising receiving the plurality of encoded signals to the centralized server over an Internet Protocol (IP) network. 
     
     
         5 . The method of  claim 1 , further comprising:
 multiplexing the plurality of encoded signals to generate a single encoded output stream; and   transmitting the single encoded output stream to the centralized server.   
     
     
         6 . A system comprising:
 a plurality of encoder sets each having one or more encoders and configured to encode an input signal for generating a plurality of encoded signals for a corresponding channel; and   a centralized server configured to:   receive the plurality of encoded signals;   receive a channel request from a subscriber;   determine one or more transmission characteristics associated the subscriber;   identify a channel with a suitable bit rate from the plurality of encoded signals based on the one or more transmission characteristics; and   transmit the channel with the identified suitable bit rate to the subscriber in response to the channel request.   
     
     
         7 . The system of  claim 6 , where each encoder in each encoder set encodes the input signal for the corresponding channel using a different encoding bit rate to generate channels with different bit rates. 
     
     
         8 . The system of  claim 6 , where each encoder set includes a first encoder with a first bit rate, a second encoder with a second bit rate higher than the first bit rate, and a third encoder with a third bit rate higher than the second bit rate, the first encoder, the second encoder, and the third encoder configured to encode each corresponding channel using the first bit rate, the second bit rate, and the third bit rate. 
     
     
         9 . The system of  claim 8 , where the first bit rate is an aggressive bit rate, the second bit rate is an average bit rate, and the third bit rate is non-aggressive bit rate. 
     
     
         10 . The system of  claim 6 , where the centralized server includes one or more rate components configured to:
 identify an available bandwidth associated with the subscriber as one of the one or more transmission characteristics; and   identify, based on the identified available bandwidth, the channel with the identified suitable bit rate.   
     
     
         11 . The system of  claim 10 , where the one or more rate components are configured to:
 identify a channel with a highest bit rate as the channel with the suitable bit rate; and   transmit, in response to the channel request, the identified channel to the subscriber.   
     
     
         12 . The system of  claim 10 , where the one or more rate components are further configured to determine a current bandwidth in use by the subscriber, and identify the channel with the highest bit rate based on the available bandwidth and the current bandwidth in use by the subscriber. 
     
     
         13 . The system of  claim 10 , where the one or more rate components include a bit rate engine configured to determine a current available bandwidth per subscriber or bit rate usage per subscriber as the identified available bandwidth. 
     
     
         14 . The system of  claim 10 , where the one or more rate components include a bit rate engine configured to receive one or more rule sets associated with prioritizing the plurality of encoded signals, and determine an appropriate combination of the plurality of encoded signals for transmission to the subscriber based on the priority. 
     
     
         15 . The system of  claim 10 , where the one or more rate components are configured to:
 monitor the available bandwidth;   detect a change in the available bandwidth based on the monitoring; and   identify a second channel different from the channel with the identified suitable bit rate for transmission to the subscriber in response to the channel request.   
     
     
         16 . The system of  claim 15 , where, upon detecting a change in the available bandwidth, the one or more rate components are configured to:
 determine whether a new channel with a bit rate higher than the channel with the suitable bit rate is available; and   if so, identify the new channel as the second channel for transmission to the subscriber.   
     
     
         17 . The system of  claim 10 , where the one or more rate components include a multiplexer to:
 multiplex a selected encoded channel from each encoder set to generate a single output multiplexed stream; and   transmit the single output multiplexed stream to the subscriber to be de-multiplexed.   
     
     
         18 . The system of  claim 6 , further comprising:
 a distribution backbone of a telecommunication system to receive the plurality of encoded signals from the plurality of encoder sets, and to send the plurality of encoded signals to the centralized server.   
     
     
         19 . The system of  claim 18 , where the centralized server includes one or more digital subscriber line access multiplexers to receive subscriber signals from multiple customer digital subscriber lines, and to transfer the subscriber signals to the distribution backbone of the telecommunication system. 
     
     
         20 . The system of  claim 18 , further comprising:
 one or more redundant switches coupled between the plurality of encoded sets and the distribution backbone of the telecommunication system to provide fault tolerant delivery of the plurality of encoded signals.