Signals having quantized values and variable length codes

• US 6,604,069 B1
• Filed: 04/06/1999
• Issued: 08/05/2003
• Est. Priority Date: 01/30/1996
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Tsutsui, Kyoya
• Primary Examiner(s): {haeck over (S)}mits, Ta̅livaldis Ivars
• Application Number:
  US09/286,772
• Time in Patent Office: 1,582 Days
• Field of Search: 704/204, 704/229, 704/500, 704/200.1
• US Class Current: 704/200.1
• CPC Class Codes: G06T 9/005 Statistical coding, e.g. Huffman, run length coding
• CPC Class Codes: G06T 9/007 Transform coding, e.g. discrete cosine transform
• CPC Class Codes: H04B 1/665 using psychoacoustic properties of the ear, e.g. masking effect

Abstract

Efficiently encoded signals wherein the compression ration can be high without a corresponding degradation of signal quality. The range of values of subband-based signal components for quantization to zero, to which a short codelength is given, is set so as to be larger. Consequently the ratio of the subband-based signal components quantized to values of a shorter codelength will become higher than if the subband-based signal components are quantized in such a manner as to minimize the total quantization error energy in each frequency band.

Claims

1. An encoded data signal readable by a device and transmitted in a data transmission medium, the encoded data signal comprising:

quantized values of signal components in a plurality of frequency subbands of a frequency spectrum;

quantization precision values for the signal components of each subband, wherein the quantization precision is higher where the quantized values are larger and lower where the quantized values are smaller; and

variable-length codes for the quantized values, wherein the code lengths are longer if the quantization precision value is higher, and shorter if the quantization precision value is lower.

2. The encoded data signal of claim 1, further comprising:

normalized signal components in each subband.

3. The encoded data signal of claim 2, wherein the signal components are coefficient normalized and the coefficient approximates a maximum absolute value of a spectral signal component of each subband.

4. The encoded data signal of claim 3, wherein a ratio of shorter to longer codelengths is higher than if the subband-based signal components had been quantized in such a manner as to minimize the total quantization error energy in each subband.

5. The encoded data signal of any of claims 1, 3, or 4, wherein the encoded data signal is representative of an acoustic signal.

6. The encoded data signal of claim 5, wherein the frequency subbands are narrower in the low frequency ranges and broader in the high frequency ranges, based upon psychoacoustic characteristics of human hearing.

7. An encoded data signal measurable by a device and transmitted in a data transmission medium, the encoded data signal comprising:

quantized values of signal components in a plurality of frequency subbands of a frequency spectrum;

quantization precision values for the signal components of each subband, wherein the quantization precision is higher where the quantized values are larger and lower where the quantized values are smaller; and

variable-length codes for the quantized values, wherein the code lengths are longer if the quantization precision value is higher, and shorter if the quantization precision value is lower.

8. The encoded data signal of claim 7, further comprising:

normalized signal components in each subband.

9. The encoded data signal of claim 8, wherein the signal components are coefficient normalized and the coefficient approximates a maximum absolute value of a spectral signal component of each subband.

10. The encoded data signal of claim 9, wherein a ratio of shorter to longer codelengths is higher than if the subband-based signal components had been quantized in such a manner as to minimize the total quantization error energy in each subband.

11. The encoded data signal of any of claims 7, 9, or 10, wherein the encoded data signal is representative of an acoustic signal.

12. The encoded data signal of claim 11, wherein the frequency subbands are narrower in the low frequency ranges and broader in the high frequency ranges, based upon psychoacoustic characteristics of human hearing.

13. A data signal which has been encoded by a device and transmitted in a data transmission medium, the encoded data signal comprising:

quantized values of signal components in a plurality of frequency subbands of a frequency spectrum;

quantization precision values for the signal components of each subband, wherein the quantization precision is higher where the quantized values are larger and lower where the quantized values are smaller; and

variable-length codes for the quantized values, wherein the code lengths are longer if the quantization precision value is higher, and shorter if the quantization precision value is lower.

14. The encoded data signal of claim 13, further comprising:

normalized signal components in each subband.

15. The encoded data signal of claim 14, wherein the signal components are coefficient normalized and the coefficient approximates a maximum absolute value of a spectral signal component of each subband.

16. The encoded data signal of claim 15, wherein a ratio of shorter to longer codelengths is higher than if the subband-based signal components had been quantized in such a manner as to minimize the total quantization error energy in each subband.

17. The encoded data signal of any of claims 13, 15, or 16, wherein the encoded data signal is representative of an acoustic signal.

18. The encoded data signal of claim 17, wherein the frequency subbands are narrower in the low frequency ranges and broader in the high frequency ranges, based upon psychoacoustic characteristics of human hearing.

19. An encoded data signal transmitted in a data transmission medium and operative to control, in part, the operation of a decoding apparatus, the encoded data signal comprising:

quantized values of signal components in a plurality of frequency subbands of a frequency spectrum;

quantization precision values for the signal components of each subband, wherein the quantization precision is higher where the quantized values are larger and lower where the quantized values are smaller; and

variable-length codes for the quantized values, wherein the code lengths are longer if the quantization precision value is higher, and shorter if the quantization precision value is lower.

20. The encoded data signal of claim 19, further comprising:

normalized signal components in each subband.

21. The encoded data signal of claim 20, wherein the signal components are coefficient normalized and the coefficient approximates a maximum absolute value of a spectral signal component of each subband.

22. The encoded data signal of claim 21, wherein a ratio of shorter to longer codelengths is higher than if the subband-based signal components had been quantized in such a manner as to minimize the total quantization error energy in each subband.

23. The encoded data signal of any of claims 19, 21, or 22, wherein the encoded data signal is representative of an acoustic signal.

24. The encoded data signal of claim 23, wherein the frequency subbands are narrower in the low frequency ranges and broader in the high frequency ranges, based upon psychoacoustic characteristics of human hearing.

25. An encoded data signal readable by a device, the encoded data signal comprising:

quantized values of signal components in a plurality of frequency subbands of a frequency spectrum;

quantization precision values for the signal components of each subband, wherein the quantization precision is higher where the quantized values are larger and lower where the quantized values are smaller; and

variable-length codes for the quantized values, wherein the code lengths are longer if the quantization precision value is higher, and shorter if the quantization precision value is lower.

26. The encoded data signal of claim 25, further comprising:

normalized signal components in each subband.

27. The encoded data signal of claim 26, wherein the signal components are coefficient normalized and the coefficient approximates a maximum absolute value of a spectral signal component of each subband.

28. The encoded data signal of claim 27, wherein a ratio of shorter to longer codelengths is higher than if the subband-based signal components had been quantized in such a manner as to minimize the total quantization error energy in each subband.

29. The encoded data signal of any of claims 25, 27, or 28, wherein the encoded data signal is representative of an acoustic signal.

30. The encoded data signal of claim 29, wherein the frequency subbands are narrower in the low frequency ranges and broader in the high frequency ranges, based upon psychoacoustic characteristics of human hearing.

31. An encoded data signal measurable by a device, the encoded data signal comprising:

quantized values of signal components in a plurality of frequency subbands of a frequency spectrum;

quantization precision values for the signal components of each subband, wherein the quantization precision is higher where the quantized values are larger and lower where the quantized values are smaller; and

variable-length codes for the quantized values, wherein the code lengths are longer if the quantization precision value is higher, and shorter if the quantization precision value is lower.

32. The encoded data signal of claim 31, further comprising:

normalized signal components in each subband.

33. The encoded data signal of claim 32, wherein the signal components are coefficient normalized and the coefficient approximates a maximum absolute value of a spectral signal component of each subband.

34. The encoded data signal of claim 33, wherein a ratio of shorter to longer codelengths is higher than if the subband-based signal components had been quantized in such a manner as to minimize the total quantization error energy in each subband.

35. The encoded data signal of any of claims 31, 33, or 34, wherein the encoded data signal is representative of an acoustic signal.

37. A data signal which has been encoded by a device, the encoded data signal comprising:

quantized values of signal components in a plurality of frequency subbands of a frequency spectrum;

quantization precision values for the signal components of each subband, wherein the quantization precision is higher where the quantized values are larger and lower where the quantized values are smaller; and

variable-length codes for the quantized values, wherein the code lengths are longer if the quantization precision value is higher, and shorter if the quantization precision value is lower.

36. The encoded data signal of claim 37, wherein the frequency subbands are narrower in the low frequency ranges and broader in the high frequency ranges, based upon psychoacoustic characteristics of human hearing.

38. The encoded data signal of claim 37, further comprising:

normalized signal components in each subband.

39. The encoded data signal of claim 38, wherein the signal components are coefficient normalized and the coefficient approximates a maximum absolute value of a spectral signal component of each subband.

40. The encoded data signal of claim 39, wherein a ratio of shorter to longer codelengths is higher than if the subband-based signal components had been quantized in such a manner as to minimize the total quantization error energy in each subband.

41. The encoded data signal of any of claims 37, 39, or 40, wherein the encoded data signal is representative of an acoustic signal.

42. The encoded data signal of claim 41, wherein the frequency subbands are narrower in the low frequency ranges and broader in the high frequency ranges, based upon psychoacoustic characteristics of human hearing.

43. An encoded data signal operative to control, in part, the operation of a decoding apparatus, the encoded data signal comprising:

quantized values of signal components in a plurality of frequency subbands of a frequency spectrum;

quantization precision values for the signal components of each subband, wherein the quantization precision is higher where the quantized values are larger and lower where the quantized values are smaller; and

variable-length codes for the quantized values, wherein the code lengths are longer if the quantization precision value is higher, and shorter if the quantization precision value is lower.

44. The encoded data signal of claim 43, further comprising:

normalized signal components in each subband.

45. The encoded data signal of claim 44, wherein the signal components are coefficient normalized and the coefficient approximates a maximum absolute value of a spectral signal component of each subband.

46. The encoded data signal of claim 45, wherein a ratio of shorter to longer codelengths is higher than if the subband-based signal components had been quantized in such a manner as to minimize the total quantization error energy in each subband.

47. The encoded data signal of any of claims 43, 45, or 46, wherein the encoded data signal is representative of an acoustic signal.

48. The encoded data signal of claim 47, wherein the frequency subbands are narrower in the low frequency ranges and broader in the high frequency ranges, based upon psychoacoustic characteristics of human hearing.

49. An encoded data signal embodied in a carrier wave and operative to control, in part, the operation of a decoding apparatus, the encoded data signal comprising:

quantized values of signal components in a plurality of frequency subbands of a frequency spectrum;

quantization precision values for the signal components of each subband, wherein the quantization precision is higher where the quantized values are larger and lower where the quantized values are smaller; and

variable-length codes for the quantized values, wherein the code lengths are longer if the quantization precision value is higher, and shorter if the quantization precision value is lower.