Adaptive transform coding system, adaptive transform decoding system and adaptive transform coding/decoding system

Abstract

In an adaptive transform coding system and/or and adaptive transform decoding system, coding efficiency in the case where a small number of quantized values having large absolute value are present, is improved. The adaptive transform coding system codes the small number of quantized values having large absolute values and other quantized values are coded separately. More particularly, the adaptive transform coding system includes a selector ( 6 ) discriminating the small number of quantized value having large absolute value from other quantized value, a pulse coding means for coding the small number of quantized values having large absolute values ( 8 ) and the pulse decoding means ( 16 ) for decoding the same, a coding means ( 7 ) for coding the quantized value other than those having large absolute values and a decoding means ( 15 ) decoding the same, and a synthesis means ( 18 ) for synthesizing the small number of quantized values having large absolute value and other quantized values.

1. An adaptive transform coding system comprising:
 a transform means for transforming an input signal into a frequency domain signal;    an analysis means for analyzing said input signal and said frequency domain signal to derive an allowable quantization error;    a quantizing means for quantizing the amplitude value of said frequency domain signal on the basis of a quantization step size to derive a quantized value and a quantization error,    a quantization parameter determining means for determining said quantization step size with reference to said allowable quantization error and said quantization error and a total code amount;    a selector for analyzing the quantized value of said frequency domain signal to derive a first signal and a second signal;    a first coding means for coding said quantized value of said first signal with reference to said second signal to derive a first code and a first code amount;    a second coding means for coding said quantized value of said second signal to derive a second code and a second code amount;    a parameter coding means for coding said quantization step size to derive a third code and a third code amount;    an adder for deriving said total code amount of said first code amount, said second code amount and said third code amount; and    a multiplexer for multiplexing said first code, said second code and said third code to generate a bit stream.    
     
     
       2. An adaptive transform coding system as set forth in  claim 1 , wherein said selector divides the quantized value of said frequency domain signal into a first signal and a third signal to generate a fourth signal, in which the absolute value of said quantized value of said first signal is replaced with smaller quantized value, and said second signal is generated by combining said third signal and said fourth signal. 
     
     
       3. An adaptive transform coding system as set forth in  claim 1 , wherein said selector derives said first signal and said second signal so that said total code amount becomes minimum. 
     
     
       4. An adaptive transform coding system as set forth in  claim 1 , wherein said first coding means generates said first code by coding the absolute value of said quantized value of said first signal, the polarity of the quantized value of said first signal and a frequency of said first signal. 
     
     
       5. An adaptive transform coding system as set forth in  claim 4 , wherein said first coding means derives a threshold value for said quantized value of said first signal to code a value derived by subtracting said threshold value from said quantized value of said first signal in place of said absolute value of said quantized value of said first signal. 
     
     
       6. An adaptive transform coding system as set forth in  claim 5 , wherein, in each sample of said first signal, the threshold value is value derived by adding one for the absolute value of the quantized value of a sample of said second signal at the same frequency to the sample of said first signal. 
     
     
       7. An adaptive transform coding system as set forth in  claim 5 , wherein a region of quantized value to be coded in said second coding means is limited, and in each sample of said first signal, said threshold value is a value derived by adding one to a maximum absolute value of an input region of said second coding means upon coding the signal having the same frequency as that of said sample by said second coding means. 
     
     
       8. An adaptive transform coding system as set forth in  claim 4 , wherein said first coding means codes the frequency of each sample of said first signal in sequential ascending order of the frequency, and for the sample other than said sample having the lowest frequency, a difference between the frequency of the sample and the frequency of the sample of the one preceding order are coded. 
     
     
       9. An adaptive transform coding system as set forth in  claim 8 , wherein said frequency signal is divided into a plurality of regions, and in said first coding means, in place of the frequency of the sample having the lowest frequency, the number of boundaries lower than said frequency of the sample having the lowest frequency, and the difference between said frequency of the sample having the lowest frequency and the maximum value in the region boundary frequencies lower than said frequency of the sample having the lowest frequency, are encoded. 
     
     
       10. An adaptive transform decoding system comprising:
 a demultiplexer for separating an input signal into a first code, a second code and a third code;    a first decoding means for decoding said first code with reference to said second code to derive a first signal;    a second decoding means for decoding said second code to derive a second signal;    a parameter decoding means for decoding said third signal to derive a quantization step size;    a synthesis means for synthesizing said first signal and said second signal for deriving a synthesized signal;    an inverse quantizing means for inverse quantizing said quantized value of said synthesized signal to derive an inverse quantized signal; and    an inverse transform means for transforming said inverse quantized signal into a time domain to derive a time domain signal.    
     
     
       11. An adaptive transform decoding system as set forth in  claim 10 , wherein said first decoding means derives a frequency of the quantized value, an absolute value of the quantized value and a sign of the quantized value by decoding said first code to set a frequency of the quantized value, an absolute value of the quantized value and a sign of the quantized value of said first signal, respectively. 
     
     
       12. An adaptive transform decoding system as set forth in  claim 11 , wherein said first decoding means derives a threshold value and takes a value derived by adding said threshold value to the absolute value of the quantized value derived by decoding said first code as an absolute value of the quantized value of said first signal, in place of the absolute value of the quantized value derived by decoding said first code. 
     
     
       13. An adaptive transform decoding system as set forth in  claim 12 , wherein, in each sample of said first signal, the threshold value is an absolute value of the quantized value of the sample of said second signal of the same frequency to said sample. 
     
     
       14. An adaptive transform decoding system as set forth in  claim 12 , wherein said second decoding means has restriction in an inverse quantized value, and in each sample of said first signal, the threshold value is a value derived by adding one to the maximum absolute value of said restriction when said second decoding means decodes the signal having the same frequency as said sample. 
     
     
       15. An adaptive transform decoding system as set forth in  claim 11 , wherein said first decoding means derives a difference between the frequency and the frequency of the sample of the lowest frequency by decoding, and derives the frequency of the sample other than said sample having the lowest frequency by cumulatively adding the difference of said frequency to the frequency of the sample having the lowest low frequency. 
     
     
       16. An adaptive transform decoding system as set forth in  claim 15 , wherein the frequency signal is divided into a plurality of region, in said first decoding means, the number of region boundaries and the difference between said frequencies are derived by decoding, and a value derived by adding a difference of said frequencies to a frequency of region boundary indicated by said number of region boundary is taken as the frequency of the sample having the lowest frequency. 
     
     
       17. An adaptive transform decoding system as set forth in  claim 10 , wherein said synthesis means generates a signal replacing the quantized value of the sample having the same frequency as the frequency of each sample of said first signal with the quantized value of said first signal to take the replaced signal as said synthesized signal. 
     
     
       18. An adaptive transform coding and decoding system comprising:
 a transform means for transforming an input signal into a frequency domain signal;    an analysis means for analyzing said input signal and said frequency domain signal to derive an allowable quantization error;    a quantizing means for quantizing amplitude value of said frequency domain signal on the basis of a quantization step size to derive a quantized value and a quantization error,    a quantization parameter determining means for determining said quantization step size with reference to said allowable quantization error and said quantization error and a total code amount;    a selector for analyzing the quantized value of said frequency domain signal to derive a first signal and a second signal;    a first coding means for coding said quantized value of said first signal with reference to said second signal to derive a first code and a first code amount;    a second coding means for coding said quantized value of said second signal to derive a second code and a second code amount;    a parameter coding means for coding said quantization step size to derive a third code and a third code amount;    an adder for deriving said total code amount of said first code amount, said second code amount and said third code amount;    a multiplexer for multiplexing said first code, said second code and said third code to generate a bit stream    a demultiplexer for separating an input signal into a first code, a second code and a third code;    a first decoding means for decoding said first code with reference to said second code to derive a first signal;    a second decoding means for decoding said second code to derive a second signal;    a parameter decoding means for decoding said third signal to derive a quantization step size;    a synthesis means for synthesizing said first signal and said second signal for deriving a synthesized signal;    an inverse quantizing means for inverse quantizing said quantized value of said synthesized signal to derive an inverse quantized signal; and    an inverse transform means for transforming said inverse quantized signal into a time domain to derive a time domain signal.    
     
     
       19. An encoding system comprising:
   transform means for transforming an input signal into a signal in a frequency domain;        replacing means for replacing a portion of said signal in the frequency domain with a replaced element having a different amplitude from that of said portion;        first encoding means for encoding the difference in amplitudes between said portion and the replaced element into a first code and for encoding a position information of said replaced element in said signal into a second code; and        multiplexing means for multiplexing said first code and said second code to generate a bitstream.      
     
     
       20. The encoding system as set forth in  claim 19 , wherein said multiplexing means multiplexes a third code which relates to the number of said replaced elements with said bitstream.  
     
     
       21. The encoding system as set forth in  claim 19 , further comprising:
   encoding means for encoding said amplitude of said replaced element.     
     
     
       22. The encoding system as set forth in  claim 19 , wherein said frequency signal is divided into a plurality of regions, wherein at least one of said position information of said replaced elements is indicated in relation to a frequency which is predetermined relating to said plurality of regions.  
     
     
       23. A decoding system comprising:
   demultiplexing means for demultiplexing a bitsteam into a first code and a second code indicative of a replacement information of a portion of a signal;        decoding means for decoding said first code to generate amplitude replacement information and for decoding said second code to generate a position information to identify said portion in said signal;        reconstructing means for reconstructing said portion of said signal by modifying the amplitude of said portion with said amplitude replacement information; and        inverse transform means for inverse transforming said reconstructed signal into a time domain signal.      
     
     
       24. The decoding system as set forth in  claim 23 , wherein said demultiplexing means demultiplexes said bitstream and obtains a third code indicative of the number of the replaced elements of a portion of a signal.  
     
     
       25. The decoding system as set forth in  claim 23 , wherein:
   said demultiplexing means demultiplexes said bitstream and obtains a code indicative of amplitude information of a portion of a signal; and        said decoding means further decodes said code indicative of amplitude information of a portion of a signal to generate said amplitude of said portion.     
     
     
       26. The decoding system as set forth in  claim 25 , wherein said signal is divided into a plurality of regions, wherein at least one of said frequencies of said replacement information of a portion of a signal is indicated in relation to a frequency which is predetermined relating to said plurality of regions. 
     
     
       27. A system including an encoding system and a decoding system, said encoding ststem comprising:
   replacing means for replacing a portion of a signal with a replaced element with a different amplitude from that of said portion;        first encoding means for encoding the difference in amplitudes between said portion and the replaced element into a first code and for encoding the position information of said replaced element in said signal into a second code; and        multiplexing means for multiplexing said first code and said second code to generate a bitstream; and        said decoding system comprising:        demultiplexing means for demultiplexing said bitsteam into said first code and said second code;        first decoding means for decoding said first code to generate the difference in amplitudes between said portion and said replaced element and decoding said second code to generate said position information of said replaced element in said signal; and        reconstructing means for reconstructing said portion of said signal,        wherein said portion is identified by said position information and the amplitude of said portion is modified using said amplitude information that represents the difference in amplitudes between said portion of said signal and said element.      
     
     
       28. The system as set forth in  claim 27 , wherein said multiplexing means multiplexes a third code which relates to the number of said replaced elements with said bitstream, and wherein said demultiplexing means demultiplexes said bitstream and obtains said third code which relates to the number of said replaced elements.  
     
     
       29. The system as set forth in  claim 28 , wherein said encoding system further comprises:
   dividing means for dividing an input signal into said first signal, said second signal and a third signal; and        second encoding means for encoding said third signal by means which is different from said first encoding means; and        wherein said decoding system further comprises:        second decoding means for decoding said third signal by means which is different from said first decoding means; and        synthesis means for synthesizing said replaced elements and said third signal to derive a synthesized signal.      
     
     
       30. The system as set forth in  claim 29 , wherein said encoding means further comprises:
   transform means for transforming the input time domain signal into a frequency domain signal; and        wherein said decoding means further comprises:        inverse transform means for transforming said synthesized signal into a time domain signal.      
     
     
       31. The system as set forth in  claim 30 , wherein said frequency domain signal is divided into a plurality of regions, wherein at least one of said frequencies of said replaced elements is indicated in relation to a frequency which is predetermined relating to said plurality of regions.  
     
     
       32. An encoding system comprising:
   a selector that replaces a portion of a signal with a replaced element having a different amplitude from that of said portion;        a pulse coding unit that encodes the difference in amplitudes between said portion and the replaced element into a first code and encodes a position information of said replaced element in said signal into a second code; and        a multiplexer that multiplexes said first code and said second code to generate a bitstream.      
     
     
       33. The encoding system as set forth in  claim 32 , wherein said multiplexer multiplexes a third code which relates to the number of said replaced elements with said bitstream.  
     
     
       34. The encoding system as set forth in  claim 33 , further comprising:
   a transform unit that transforms an input signal into a frequency signal;        wherein said selector and said pulse coding unit divide said input signal into said first signal, said second signal and a third signal; and        a coding unit that encodes said third signal by means which is different from said pulse coding unit.      
     
     
       35. The encoding system as set forth in  claim 34 , wherein said frequency signal is divided into a plurality of regions, wherein at least one of said frequencies of said replaced elements is indicated in relation to a frequency which is predetermined relating to said plurality of regions.  
     
     
       36. A decoding system comprising:
   a demultiplexer that demultiplexes a bitsteam into a first code and a second code indicative of replacement information of a portion of a signal;        a pulse decoding unit that decodes said first code to generate amplitude replacement information and for decoding said second code to generate position information to identify said portion of said signal and reconstructs said portion of said signal;        wherein said portion is identified by said position information and the amplitude of said portion is modified using said amplitude replacement information.      
     
     
       37. The decoding system as set forth in  claim 36 , wherein said demultiplexer demultiplexes said bitstream into the second code indicative of replacement information of said portion of said signal.  
     
     
       38. The decoding system as set forth in  claim 37 , wherein said pulse decoding unit decodes said second code to generate the position information to identify said portion in said signal.  
     
     
       39. The decoding system as set forth in  claim 38 , wherein said demultiplexer demultiplexes said bitstream and obtains a third code indicative of replacement information of a portion of a signal.  
     
     
       40. The decoding system as set forth in  claim 39 , further comprising:
   a synthesis unit that synthesizes said replacement information of a portion of a signal and a signal decoded by means different from said pulse decoding unit to derive a synthesized signal.      
     
     
       41. The decoding system as set forth in  claim 40 , further comprising:
   a inverse transform unit transforms said synthesized signal into a time domain signal.      
     
     
       42. The decoding system as set forth in  claim 40 , wherein said signal is divided into a plurality of regions, wherein at least one of said frequencies of said replacement information of a portion of a signal is indicated in relation to a frequency which is predetermined relating to said plurality of regions.  
     
     
       43. A system including an encoding system and a decoding system,
   said encoding system comprising:        a selector that replaces a portion of a signal with a replaced element with a different amplitude from that of said portion;        a pulse coding unit that that encodes the difference in amplitudes between said portion and the replaced element into a first code and for encoding the position information of said replaced element in said signal into a second code; and        a multiplexer that multiplexes said first code and said second code to generate a bitstream; and        said decoding system comprising:      a demultiplexer that demultiplexes said bitsteam into said first code and said second code; and        a pulse decoding unit that decodes said first code to generate the difference in amplitudes between said portion and said replaced element and decodes said second code to generate said position information of said replaced element in said signal; and        wherein said pulse decoding unit reconstructs said portion of said signal,        wherein said portion is identified by said position information and the amplitude of said portion is modified using said amplitude information that represents the difference in amplitudes between said portion of said signal and said replaced element.        
     
     
       44. The system as set forth in  claim 43 , wherein said multiplexer multiplexes a third code which relates to the number of said replaced elements with said bitstream, and wherein said demultiplexer demultiplexes said bitstream and obtains said third code which relates to the number of said replaced elements.  
     
     
       45. The system as set forth in  claim 44 , wherein said encoding system further comprises:
   the selector and pulse coding unit dividing an input signal into said first signal, said second signal and a third signal; and        a coding unit that encodes said third signal by means which is different from said pulse coding unit; and        wherein said decoding system further comprises:        a decoding unit that decodes said third signal by means which is different from said pulse decoding unit; and        a synthesis unit that synthesizes said replaced elements and said third signal to derive a synthesized signal.      
     
     
       46. The system as set forth in  claim 45 , wherein said encoding system further comprises:
   a transform unit that transform an input time domain signal into a frequency domain signal; and        wherein said decoding system further comprises:        an inverse transform unit that transforms said synthesized signal into a time domain signal.      
     
     
       47. The system as set forth in  claim 46 , wherein said frequency domain signal is divided into a plurality of regions, wherein at least one of said frequencies of said replaced elements is indicated in relation to a frequency which is predetermined relating to said plurality of regions.  
     
     
       48. The encoding system as set forth in  claim 20 , further comprising second encoding means for encoding said number into said third code by means which is different from said first encoding means. 
     
     
       49. The encoding system as set forth in  claim 33 , further comprising an encoding unit that encodes said number into said third code by means which is different from said first encoding means.