Quantization of speech and audio coding parameters using partial information on atypical subsequences

• US 7,885,809 B2
• Filed: 04/19/2006
• Issued: 02/08/2011
• Est. Priority Date: 04/20/2005
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Ramprashad, Sean A.
• Primary Examiner(s): Smits; Talivaldis I
• Assistant Examiner(s): ROBERTS, SHAUN A
• Application Number:
  US11/408,125
• Publication Number:
  US 20060241940A1
• Time in Patent Office: 1,756 Days
• Field of Search: 704/229, 704/230, 704/222, 704/500
• US Class Current: 704/222
• CPC Class Codes: G10L 19/028 Noise substitution, i.e. substituting non-tonal spectral components by noisy source comfort noise for discontinuous speech transmission G10L19/012
• CPC Class Codes: G10L 19/032 Quantisation or dequantisation of spectral components

Abstract

A method and apparatus is disclosed herein for a quantizing parameters using partial information on atypical subsequences. In one embodiment, the method comprises partially classifying a first plurality of subsequences in a target vector into a number of selected groups, creating a refined fidelity criterion for each subsequence of the first plurality of subsequences based on information derived from classification, dividing a target vector into a second plurality of subsequences, and encoding the second plurality of subsequences, including quantizing the second plurality of subsequences given the refined fidelity criterion.

Claims

1. A method comprising:

partially ordering, by an encoder of a processing device, a first plurality of subsequences of a target vector by arranging subsequences of the first plurality of subsequences into a plurality of ordered groups in accordance with a measure of the target vector available only to the encoder and not available to a decoder, wherein membership in an ordered group represents a variation of behavior of subsequences of the first plurality of subsequences, wherein order of groups in the plurality of ordered groups does not provide information on element by element values of the target vector itself, wherein the subsequences in each ordered group are not differentiated and are given equal priority within the ordered group, and wherein information specifying the partial ordering of the first plurality of subsequences into the plurality of ordered groups is explicitly encoded into a number of bits sent to the decoder that represents an arrangement of the first plurality of subsequences into the ordered groups, wherein the bits specify only the partial ordering and define only the subsequences in each ordered group and the order of the plurality of ordered groups, and wherein the partial ordering is fully recoverable using the information;

dividing, by the encoder, the subsequences of the first plurality of subsequences into a second plurality of subsequences;

creating, by the encoder, a subsequence fidelity criterion for each subsequence of the second plurality of subsequences based at least in part on the partial ordering of the first plurality of subsequences represented through the arrangement of the first plurality of subsequences into groups; and

encoding, by the encoder, the second plurality of subsequences, including quantizing the second plurality of subsequences, given each of the subsequence fidelity criterions.

2. The method defined in claim 1 wherein each subsequence fidelity criterion is mapped to a bit allocation, wherein quantizing the second plurality of subsequences is in accordance with the bit allocation, and wherein the bit allocation tries not to differentiate between subsequences of the same group.

3. The method defined in claim 1 further comprising:

mapping the partial ordering of the first plurality of subsequences to a unique index;

encoding the index; and

sending the index in the bitstream.

4. The method defined in claim 3 further comprising adding the resulting quantization information of the second plurality of subsequences into the bitstream along with the index specifying the partial order, wherein the index allows a receiver of the bitstream to reconstruct a meaning of the quantization information.

5. The method defined in claim 2 wherein creating each of the subsequence fidelity criterions is based on information derived from classification and includes modifying an existing fidelity criterion that applies only globally to encoding the entire target vector.

6. The method defined in claim 5 wherein the global fidelity criterion is a total number of bits that can be used to encode the target vector, and wherein the subsequence bit allocation conforms to the global fidelity criterion.

7. The method defined in claim 1 wherein the target vector has no assumed redundancy or statistical structure for apparent classification into the ordered groups.

8. The method defined in claim 1 wherein a measure of the variation of a subsequence is not precisely defined, is not sent in the bitstream, and is implied imprecisely through a group membership in one of the ordered groups and through a ordering of the ordered groups.

9. The method defined in claim 1 further comprising grouping one or more types of variations by considering the variation with respect to a statistical norm.

10. The method defined in claim 1 wherein partially ordering the first plurality of subsequences into groups comprises:

detecting variations in the first plurality of subsequences, classifying the variations, grouping the variations into two or more groups, assigning subsequences to the groups, ordering the groups, and not transmitting the variations.

11. The method defined in claim 10 wherein arranging the subsequences into a plurality of ordered groups based on the measure of variation is based on a measure of energy.

12. The method defined in claim 1 wherein classifying variations is based on testing performance of quantizing individual targets with all possible refinements of the global fidelity criterion that can be represented by a partial order.

13. The method defined in claim 1 wherein arranging the subsequences into a plurality of ordered groups based on the measure of variation is based on testing a number of possible classification options and the respective bit assignments and selecting the option that has a desired level of performance given a criterion.

14. The method defined in claim 1 wherein arranging the subsequences into a plurality of ordered groups based on the measure of variation is based on trying to maximize the number of the first plurality of sequences that do not receive quantization resources in each of the subsequence fidelity criterions.

15. The method defined in claim 1 further comprising creating an unequal bit assignment across the ordered groups to which the first plurality of subsequences are arranged, wherein the unequal bit assignment is a function of the group and specifies the total number of bits per group.

16. The method defined in claim 15 wherein the bit assignment across the first plurality of subsequences can be directly mapped to the bit assignment across the second plurality of subsequences by dividing the total bit assignment per group as equally as possible among group members.

17. The method defined in claim 15 wherein creating the unequal bit assignment is based on observing a statistical variation between members of different ordered groups in the plurality of ordered groups and observing that there is an order of priority between ordered groups, wherein the observed statistical variation is not specified.

18. The method defined in claim 1 wherein creating the subsequence fidelity criterion comprises generating patterns of bit assignments within each group of subsequences.

19. The method defined in claim 18 wherein creating the-subsequence fidelity criteria comprises:

determining groups of bit assignments for subsequences in the same group; and

reordering these bit assignments in a fixed fashion that is not driven by the partial ordering and assumes no priority of subsequences within the group is specified by the partial ordering.

20. The method defined in claim 19 wherein reordering the bit assignments is based on achieving a desired perceptual effect that is not implicit on the partial ordering.

21. The method defined in claim 20 wherein the desired perceptual effect is a perceptual masking property.

22. The method defined in claim 20 wherein the reordering the bit assignments comprises clustering one or more non-zero bit assignments away from an already coded area.

23. The method defined in claim 19 wherein reordering the bit assignments causes subsequences with a maximum bit allocation to be quantized before subsequences with less than the maximum bit allocation.

24. The method defined in claim 1 wherein creating the refined fidelity criterion based on information derived from classification comprises modifying the fidelity criteria to take advantage of perceptual masking effects.

25. The method defined in claim 24 wherein the perceptual masking effects are in one or more of a group consisting of effects in one or more of time and frequency.

26. The method defined in claim 1 further comprising adapting quantizers for encoding the second plurality of subsequences based on the information.

27. The method defined in claim 26 wherein adapting quantizers comprises:

for each subsequence, selecting use of one of a plurality of quantizers based on a category assigned to said each subsequence, the category being defined by group membership in the plurality of ordered groups.

28. The method defined in claim 27 wherein selecting use of one of the plurality of quantizers comprises selecting a codebook for use in quantization based on the group membership.

29. An article of manufacture comprising one or more computer readable media storing instructions which, when executed by a system, causes the system to perform a method comprising:

partially ordering a first plurality of subsequences of a target vector by arranging subsequences of the first plurality of subsequences into a plurality of ordered groups in accordance with a measure of the target vector available only to an encoder and not available to a decoder, wherein membership in an ordered group represents a variation of behavior of subsequences of the first plurality of subsequences, wherein order of groups in the plurality of ordered groups does not provide information on element by element values of the target vector itself, wherein the subsequences in each ordered group are not differentiated and are given equal priority within the ordered group, and wherein information specifying the partial ordering of the first plurality of subsequences into the plurality of ordered groups is explicitly encoded into a number of bits in a stream sent to the decoder that represents an arrangement of the first plurality of subsequences into the ordered groups, wherein the bits specify only the partial ordering define only the subsequences in each ordered group and the order of the plurality of ordered groups, and wherein the partial ordering is fully recoverable using the information;

dividing the subsequences of the first plurality of subsequences into a second plurality of subsequences;

creating a subsequence fidelity criterion for each subsequence of the second plurality of subsequences based at least in part on the partial ordering of the first plurality of subsequences represented through the arrangement of the first plurality of subsequences into groups; and

encoding the second plurality of subsequences, including quantizing the second plurality of subsequences given each of the subsequence fidelity criterions.

30. A method comprising:

decoding, by a decoder of a processing device, encoded group membership information from a received bitstream, the group membership information being a number of bits in the bitstream that were explicitly encoded to define an ordering of groups into which a first plurality of subsequences of a target vector were arranged in accordance with a measure of the target vector available only to an encoder and not available to the decoder, wherein the ordering is a partial ordering because membership in a group represents a variation of behavior of subsequences of the first plurality of subsequences, wherein order of groups in the plurality of groups does not provide information on element by element values of the target vector itself, wherein the first plurality of subsequences are unequally assigned across the plurality of groups, wherein the group membership information defines only the subsequences in each group and the order of the plurality of groups, and wherein the ordering of groups is fully recoverable using the group membership information, and wherein the one or more subsequences in each group are given equal priority within the group;

generating, by the decoder based at least in part on the decoded group membership information, a subsequence fidelity criterion for each subsequence of a second plurality of subsequences of the target vector used during encoding; and

decoding, by the decoder, the second plurality of encoded subsequences from the bitstream based on each of the subsequence fidelity criterions that define a parsing and syntax of the bitstream.

31. The method defined in claim 30 further comprising reordering the second plurality of subsequences based on order information received from the bitstream.

32. The method defined in claim 30 wherein each of the subsequence fidelity criteria comprise a bit allocation, wherein decoding of the second plurality of encoded subsequences is based on the bit allocation, and wherein the bit allocation tries not to differentiate between subsequences within the same group.

33. The method defined in claim 30 wherein generating the subsequence fidelity criteria comprises modifying a global fidelity criteria that applies only globally to encoding the target vector.

34. The method defined in claim 30 wherein the arranging of the first plurality of subsequences into groups is based on one or more types of statistical variation between the groups.

35. The method defined in claim 30 further comprising creating an unequal bit assignment across the second plurality of encoded subsequences as a function of the groups into which the first plurality of subsequences are arranged, and wherein decoding the second plurality of encoded subsequences is based on the unequal bit assignment.

36. The method defined in claim 30 wherein creating the subsequence fidelity criteria comprises generating patterns of bit assignments within each group of subsequences.

37. The method defined in claim 36 wherein creating the subsequence fidelity criteria comprises:

determining groups of bit assignments for subsequences in the same group; and

reordering the bit assignments in a fixed fashion that is not driven by the partial ordering and assumes no priority of subsequences within the group specified by the partial ordering.

38. The method defined in claim 37 wherein reordering the bit assignments is based on achieving a desired perceptual effect that is not implicit on the partial ordering.

39. The method defined in claim 38 wherein the desired perceptual effect is a perceptual masking property.

40. The method defined in claim 38 wherein reordering the bit assignments comprises clustering one or more non-zero or higher bit assignments away from an already decoded area.

41. The method defined in claim 37 wherein reordering the bit assignments causes subsequences with a maximum bit allocation to be quantized before subsequences with less than the maximum bit allocation.

42. The method defined in claim 36 further comprising generating a random sequence at prescribed energy for subsequences with no information in bits describing the quantization, the random sequence being combined with the decoded subsequences to create a decoded version of a target vector.

43. The method defined in claim 30 wherein creating the subsequence fidelity criteria comprises modifying the fidelity criteria to take advantage of perceptual masking effects.

44. The method defined in claim 43 wherein the perceptual masking effects are in one or more of a group consisting of time and frequency.

45. The method defined in claim 43 further comprising adapting the noise-fill to match an exact non-zero bit assignment pattern in the criteria.

46. An article of manufacture comprising one or more computer readable media storing instructions which, when executed by a system, causes the system to perform a method comprising:

decoding encoded group membership information from a received bitstream, the group membership information being a number of bits in the bitstream that were explicitly encoded to define an ordering of groups into which a first plurality of subsequences of a target vector were arranged in accordance with a measure of the target vector available only to an encoder and not available to a decoder, wherein the ordering is a partial ordering because membership in a group represents a variation of behavior of subsequences of the first plurality of subsequences, wherein an order of the groups does not provide information on element by element values of the target vector itself, wherein the first plurality of subsequences are unequally assigned across the plurality of groups, wherein the group membership information defines only the subsequences in each group and the order of the groups, and wherein the ordering is fully recoverable using the group membership information, and wherein the one or more subsequences in each group are given equal priority within the group;

generating, based at least in part on the decoded group membership information, a subsequence fidelity criterion for each subsequence of a second plurality of subsequences of the target vector used during encoding; and

decoding the second plurality of encoded subsequences from the bitstream based on each of the subsequence fidelity criterions that define a parsing and syntax of the bitstream.