Method and system for reduction of quantization-induced block-discontinuities and general purpose audio codec

• US 6,704,706 B2
• Filed: 02/04/2002
• Issued: 03/09/2004
• Est. Priority Date: 05/27/1999
• Status: Expired due to Term

• Current Assignee: Meta Platforms, Inc. (f/k/a Facebook, Inc.)
• Original Assignee: America Online Inc. (Warner Bros. Discovery, Inc.)
• Inventors: Mantegna, John, Wu, Shuwu
• Primary Examiner(s): ABEBE, DANIEL DEMELASH
• Application Number:
  US10/061,206
• Publication Number:
  US 20020111801A1
• Time in Patent Office: 764 Days
• Field of Search: 704/500, 704/200, 704/203, 704/222, 704/219, 704/220, 704/258, 704/265, 704/269
• US Class Current: 704/230
• CPC Class Codes: G10L 19/00 Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis in musical instruments G10H
• CPC Class Codes: G10L 19/0212 using orthogonal transformation
• CPC Class Codes: G10L 19/022 Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring
• 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 19/038 Vector quantisation, e.g. TwinVQ audio
• CPC Class Codes: G10L 2019/0012 Smoothing of parameters of the decoder interpolation

Abstract

Enabling low-latency reduction of quantization-induced block-discontinuities of continuous data formatted into a plurality of data blocks having boundaries typically includes forming an overlapping input data block by prepending a fraction of a previous input data block to a current input data block, identifying regions near the boundary of each overlapping input data block, and excluding regions near the boundary of each overlapping input data block and reconstructing an initial output data block from the remaining data of such overlapping input data block. The continuous data may include audio data and/or time-domain data. The low-latency reduction of quantization-induced block-discontinuities of continuous data may be applied to at least one of a coder and decoder.

Claims

1. A low-latency method for enabling reduction of quantization-induced block-discontinuities of continuous data formatted into a plurality of data blocks having boundaries, including:

forming an overlapping input data block by prepending a fraction of a previous input data block to a current input data block;

performing a reversible transform on each overlapping input data block to yield energy concentration in the transform domain;

quantizing each reversibly transformed block and generating quantization indices indicative of such quantization;

inversely transforming each quantized transform-domain block into an overlapping reconstructed data block; and

excluding data from regions near the boundary of each overlapping reconstructed data block and reconstructing an initial output data block from the remaining data of such overlapping reconstructed data block.

2. The method of claim 1 wherein the continuous data includes audio data.

3. The method of claim 1 wherein the continuous data includes continuous time-domain data, wherein the method further includes formatting the continuous time-domain data into a plurality of time-domain blocks having boundaries.

4. The method of claim 1 further including applying the low-latency method to at least one of a coder and a decoder.

5. The method of claim 4 wherein applying the low-latency method to at least one of the coder and the decoder includes:

encoding the quantization indices for each quantized block as an encoded block, and outputting each encoded block as a bit-stream;

decoding each encoded block into quantization indices; and

generating a quantized transform-domain block from the quantization indices.

6. The method of claim 1 further including:

interpolating boundary data between adjacent overlapping reconstructed data blocks; and

prepending the interpolated boundary data with the initial output data block to generate a final output data block.

7. The method of claim 6 further including applying a windowing function to each original input data block to enhance residue energy concentration near the boundaries of each such original input data block.

8. The method of claim 7 wherein the windowing function is substantially characterized by an identity function but with bell-shaped decays near the boundaries of a block.

9. The method of claim 1 wherein performing the reversible transform includes performing the reversible transform only on each overlapping input data block.

10. A computer program, residing on a computer-readable medium, for enabling low-latency reduction of quantization-induced block-discontinuities of continuous data formatted into a plurality of data blocks having boundaries, the computer program comprising instructions for causing a computer to:

form an overlapping input data block by prepending a fraction of a previous input data block to a current input data block;

perform a reversible transform on each overlapping input data block to yield energy concentration in the transform domain;

quantize each reversibly transformed block and generate quantization indices indicative of such quantization;

inversely transform each quantized transform-domain block into an overlapping reconstructed data block; and

exclude data from regions near the boundary of each overlapping reconstructed data block and reconstruct an initial output data block from the remaining data of such overlapping reconstructed data block.

11. The computer program of claim 10 wherein the continuous data includes audio data.

12. The computer program of claim 10 wherein the continuous data includes continuous time-domain data, wherein the computer program further includes instructions for causing the computer to format the continuous time-domain data into a plurality of time-domain blocks having boundaries.

13. The computer program of claim 10 further including instructions for causing the computer to apply the low-latency computer program to at least one of a coder and a decoder.

14. The computer program of claim 13 wherein the instruction for causing the computer to apply the low-latency computer program to at least one of the coder and the decoder include instructions for causing the computer to:

encode the quantization indices for each quantized block as an encoded block and output each encoded block as the bit-stream;

decode each encoded block into quantization indices; and

generate a quantized transform-domain block from the quantization indices.

15. The computer program of claim 10 further includes instructions causing the computer to:

interpolate boundary data between adjacent overlapping reconstructed data blocks; and

prepend the interpolated boundary data with the initial output data block to generate a final output data block.

16. The computer program of claim 15 further including instructions for causing the computer to apply a windowing function to each original input data block to enhance residue energy concentration near the boundaries of each such original input data block.

17. The computer program of claim 16 wherein the windowing function is substantially characterized by an identity function but with bell-shaped decays near the boundaries of a block.

18. The computer program of claim 10 wherein the instructions for causing the computer to perform the reversible transform include instructions for causing the computer to perform the reversible transform only on each overlapping input data block.

19. A system for enabling low-latency reduction of quantization-induced block-discontinuities of continuous data formatted into a plurality of data blocks having boundaries, including:

means for forming an overlapping input data block by prepending a fraction of a previous input data block to a current input data block;

means for performing a reversible transform on each overlapping input data block to yield energy concentration in the transform domain;

means for quantizing each reversibly transformed block and generating quantization indices indicative of such quantization;

means for inversely transforming each quantized transform-domain block into an overlapping reconstructed data block; and

means for excluding data from regions near the boundary of each overlapping reconstructed data block and reconstructing an initial output data block from the remaining data of such overlapping reconstructed data block.

20. The system of claim 19 wherein the continuous data includes audio data.

21. The system of claim 19 wherein the continuous data includes continuous time-domain data, wherein the system further includes means for formatting the continuous time-domain data into a plurality of time-domain blocks having boundaries.

22. The system of claim 19 further including means for applying the low-latency system to at least one of a coder and a decoder.

23. The system of claim 22 wherein the means for applying the low-latency system to at least one of the coder and the decoder includes:

means for encoding the quantization indices for each quantized block as an encoded block and outputting each encoded block as the bit-stream

means for decoding each encoded block into quantization indices; and

means for generating a quantized transform-domain block from the quantization indices.

24. The system of claim 19 further including:

means for interpolating boundary data between adjacent overlapping reconstructed data blocks; and

means for prepending the interpolated boundary data with the initial output data block to generate a final output data block.

25. The system of claim 24 further including means for applying a windowing function to each original input data block to enhance residue energy concentration near the boundaries of each such original input data block.

26. The system of claim 25 wherein the windowing function is substantially characterized by an identity function but with bell-shaped decays near the boundaries of a block.

27. The system of claim 19 wherein the means for performing the reversible transform includes means for performing the reversible transform only on each overlapping input data block.

28. A low-latency method for enabling reduction of quantization-induced block-discontinuities of continuous data formatted into a plurality of data blocks having boundaries, including:

forming an overlapping input data block by prepending a fraction of a previous input data block to a current input data block;

identifying regions near the boundary of each overlapping input data block; and

excluding regions near the boundary of each overlapping input data block and reconstructing an initial output data block from the remaining data of such overlapping input data block.

29. The method of claim 28 wherein identifying regions near the boundary of each overlapping input data block includes:

performing a reversible transform on each overlapping input data block to yield energy concentration in the transform domain;

quantizing each reversibly transformed block and generating quantization indices indicative of such quantization; and

inversely transforming each quantized transform-domain block into an overlapping reconstructed data block that is indicative of regions near the boundary of each overlapping input data block.

30. The method of claim 28 wherein the continuous data includes audio data.

31. The method of claim 28 wherein the continuous data includes continuous time-domain data, wherein the method further includes formatting the continuous time-domain data into a plurality of time-domain blocks having boundaries.

32. The method of claim 28 further including applying the low-latency method to at least one of a coder and a decoder.

33. The method of claim 28 further including:

interpolating boundary data between adjacent overlapping reconstructed data blocks; and

prepending the interpolated boundary data with the initial output data block to generate a final output data block.

34. The method of claim 28 further including applying a windowing function to each original input data block to enhance residue energy concentration near the boundaries of each such original input data block.

35. The method of claim 34 wherein the windowing function is substantially characterized by an identity function but with bell-shaped decays near the boundaries of a block.

36. The method of claim 29 further including applying the low-latency method to at least one of a coder and a decoder that includes:

encoding the quantization indices for each quantized block as an encoded block, and outputting each encoded block as a bit-stream;

decoding each encoded block into quantization indices; and

generating a quantized transform-domain block from the quantization indices.

37. The method of claim 29 wherein performing the reversible transform includes performing the reversible transform only on each overlapping input data block.

38. A computer program, residing on a computer-readable medium, for enabling low-latency reduction of quantization-induced block-discontinuities of continuous data formatted into a plurality of data blocks having boundaries, the computer program comprising instructions for causing a computer to:

form an overlapping input data block by prepending a fraction of a previous input data block to a current input data block;

identify regions near the boundary of each overlapping input data block; and

exclude regions near the boundary of each overlapping input data block and reconstruct an initial output data block from the remaining data of such overlapping input data block.

39. The computer program of claim 38 wherein the instructions that cause the computer to identify regions near the boundary of each overlapping input data block includes instructions for causing the computer to:

perform a reversible transform on each overlapping input data block to yield energy concentration in the transform domain;

quantize each reversibly transformed block and generate quantization indices indicative of such quantization; and

inversely transform each quantized transform-domain block into an overlapping reconstructed data block that is indicative of regions near the boundary of each overlapping input data block.

40. The computer program of claim 39 wherein the instructions for causing the computer to perform the reversible transform include instructions for causing the computer to perform the reversible transform only on each overlapping input data block.

41. A system for enabling low-latency reduction of quantization-induced block-discontinuities of continuous data formatted into a plurality of data blocks having boundaries, including:

means for forming an overlapping input data block by prepending a fraction of a previous input data block to a current input data block;

means for identifying regions near the boundary of each overlapping input data block; and

means for excluding regions near the boundary of each overlapping input data block and reconstructing an initial output data block from the remaining data of such overlapping input data block.

42. The system of claim 41 wherein the means for identifying regions near the boundary of each overlapping input data block includes:

means for performing a reversible transform on each overlapping input data block to yield energy concentration in the transform domain;

means for quantizing each reversibly transformed block and generating quantization indices indicative of such quantization; and

means for inversely transforming each quantized transform-domain block into an overlapping reconstructed data block that is indicative of regions near the boundary of each overlapping input data block.

43. The system of claim 42 wherein the means for performing the reversible transform includes means for performing the reversible transform only on each overlapping input data block.