Apparatus and method for adaptive audio coding

Abstract

An audio encoder capable of implementing a plurality of encoding functions, wherein an adaptation controller adjusts the implementation of the encoding functions in response to feedback received by the adaptation controller during use. The adjustment may involve adapting encoding algorithms or selecting alternative encoding algorithms. The encoder may also include an operations scheduler to adjust the order in which the encoding functions are applied. The feedback may be received from internally of the encoder, for example from the currently implemented encoding functions, or from externally of the encoder. A corresponding decoder is also provided.

1 . An audio encoder comprising an input for receiving samples of audio data; an output for encoded audio data; means for implementing a plurality of encoding functions; means for causing at least one of said encoding functions to be applied in use to said audio data samples to produce said encoded audio data, wherein said means for causing at least one of said encoding functions to be applied to said audio data samples comprises an operation scheduler arranged to control the order in which at least some of the encoding functions are applied to said audio data samples. 
     
     
         2 . An audio encoder as claimed in  claim 1 , wherein said operation scheduler is arranged to implement an operation schedule indicating the order in which said at least some of the encoding functions are applied to said audio data samples, and to cause said at least some of the encoding functions to be applied to said audio data samples in accordance with said operation schedule. 
     
     
         3 . An audio encoder as claimed in  claim 1 , wherein said operation scheduler is responsive to at least one characteristic of at least one of said encoding functions to cause the order in which at least some of the encoding functions are applied to said audio data samples to be changed. 
     
     
         4 . An audio encoder as claimed in  claim 3 , wherein said at least one characteristic of at least one of said encoding functions includes the respective frequency of use of the respective encoding function. 
     
     
         5 . An audio encoder as claimed in  claim 1 , wherein said operation scheduler is responsive to at least one characteristic of the audio data samples to cause the order in which at least some of the encoding functions are applied to said audio data samples to be changed. 
     
     
         6 . An audio encoder as claimed in  claim 1 , wherein the encoder is responsive to at least one feedback input to provide said operation scheduler with a new operation schedule. 
     
     
         7 . An audio encoder as claimed in  claim 6 , wherein said at least one feedback input includes signals from said implementing means in respect of one or more of said encoding functions. 
     
     
         8 . An audio encoder as claimed in  claim 6 , wherein said at least one feedback input includes signals from said operation scheduler in respect of one or more aspects of the operation of the encoder. 
     
     
         9 . An audio encoder as claimed in  claim 6 , wherein said at least one feedback input includes signals from said operation scheduler in respect of one or more characteristics of the input samples received by the encoder in use. 
     
     
         10 . An audio encoder as claimed in  claim 6 , wherein said at least one feedback input includes signals received from externally of the encoder. 
     
     
         11 . An audio encoder as claimed in  claim 10 , wherein the encoder is arranged to receive data from a decoder, said data being indicative of the configuration of the decoder, and wherein said encoder is arranged to cause the order in which at least some of the encoding functions are applied to said audio data samples to be adjusted in accordance with the configuration data received from the decoder. 
     
     
         12 . An audio encoder as claimed in  claim 1 , further including an adaptation controller arranged to adjust at least one of said implementing means and said causing means in response to at least one feedback input received by said adaptation controller during operation of said audio encoder. 
     
     
         13 . An audio encoder as claimed in  claim 12 , wherein said adaptation controller is responsive to said at least one feedback input to cause said implementing means to implement, in respect of at least one of said encoding functions, a selected one or more of a plurality of respective encoding algorithms. 
     
     
         14 . An audio encoder as claimed in  claim 12 , wherein said adaptation controller is responsive to said at least one feedback input to cause said implementing means to adapt, in respect of at least one of said encoding functions, an implementation of a selected one or more of a plurality of respective encoding algorithms. 
     
     
         15 . An audio encoder as claimed in  claim 14 , wherein the adaptation controller is arranged to provide the implementing means with at least one parameter value for adapting the implementation of the, or each, respective encoding algorithm. 
     
     
         16 . An audio encoder as claimed in  claim 12 , wherein the implementation means is co-operable with means for storing a plurality of encoding algorithms that are selectable by said adaptation controller, said implementation means being arranged to use, in the implementation of said encoding functions, one or more stored encoding algorithms selected by said adaptation controller. 
     
     
         17 . An audio encoder as claimed in  claim 15 , wherein at least some of said encoding algorithms are associated with respective performance data being indicative of at least one aspect of the performance of said encoder when implementing the respective encoding algorithm. 
     
     
         18 . An audio encoder as claimed in  claim 12 , wherein said operation scheduler is arranged to select the order in which said at least some encoding functions are applied to said audio data in response to instructions received by said operation scheduler from said adaptation controller. 
     
     
         19 . An audio encoder as claimed in  claim 18 , wherein said adaptation controller is arranged to communicate an operation schedule to said operation scheduler, said operation scheduler causing said at least some encoding functions to be applied in accordance with said operation schedule. 
     
     
         20 . An audio encoder as claimed in  claim 12 , wherein said adaptation controller is responsive to said at least one feedback input to cause said operation scheduler to change the order in which said at least some encoding functions are applied to said audio data. 
     
     
         21 . An audio encoder as claimed in  claim 10 , wherein said data included in signals received from externally of the encoder are indicative of at least one aspect of the performance or status of an external system with which said audio encoder is associated. 
     
     
         22 . An audio encoder as claimed in  claim 1 , wherein at least one of said encoding functions is arranged to adapt its operation in response to one or more characteristics of said audio data. 
     
     
         23 . An audio decoder comprising an input for receiving samples of encoded audio data; an output for decoded audio data; means for implementing a plurality of decoding functions; means for causing at least one of said decoding functions to be applied in use to said encoded audio data samples to produce said decoded audio data, wherein said means for causing at least one of said decoding functions to be applied to said encoded audio data samples comprises an operation scheduler arranged to control the order in which at least some of the decoding functions are applied to said encoded audio data samples. 
     
     
         24 . An audio decoder as claimed in  claim 23 , wherein the decoder is arranged to receive data from an encoder, said data being indicative of the configuration of the encoder, and wherein said decoder is arranged to cause the order in which at least some of the decoding functions are applied to said encoded audio data samples to be adjusted in accordance with the configuration data received from the encoder. 
     
     
         25 . An audio decoder as claimed in  claim 23 , wherein the decoder is arranged to send data to an encoder, said data being indicative of the configuration of the decoder, and to receive an acknowledgement from the encoder, and wherein said decoder is arranged to delay said adjusting of the order in which at least some of the decoding functions are applied to said encoded audio data samples until said acknowledgement is received. 
     
     
         26 . A method of audio encoding, the method comprising receiving an input comprising samples of audio data, implementing one or more of a plurality of encoding functions, applying at least one of said encoding functions to said audio data to produce encoded audio data; and controlling the order in which at least some of said encoding functions are applied to said audio data. 
     
     
         27 . A method of audio decoding, the method comprising receiving an input comprising samples of encoded audio data, implementing one or more of a plurality of decoding functions, applying at least one of said decoding functions to said encoded audio data to produce decoded audio data; and controlling the order in which at least some of said decoding functions are applied to said encoded audio data.