Multi-channel audio encoding and decoding with different window configurations

• US 7,860,720 B2
• Filed: 05/15/2008
• Issued: 12/28/2010
• Est. Priority Date: 09/04/2002
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Thumpudi, Naveen, Chen, Wei-Ge
• Primary Examiner(s): Hudspeth; David R
• Assistant Examiner(s): Rider; Justin W
• Application Number:
  US12/121,629
• Publication Number:
  US 20080221908A1
• Time in Patent Office: 957 Days
• Field of Search: None
• US Class Current: 704/500
• 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 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/0212 using orthogonal transformation

Abstract

An audio encoder and decoder use architectures and techniques that improve the efficiency of multi-channel audio coding and decoding. The described strategies include various techniques and tools, which can be used in combination or independently. For example, an audio encoder performs a pre-processing multi-channel transform on multi-channel audio data, varying the transform so as to control quality. The encoder groups multiple windows from different channels into one or more tiles and outputs tile configuration information, which allows the encoder to isolate transients that appear in a particular channel with small windows, but use large windows in other channels. Using a variety of techniques, the encoder performs flexible multi-channel transforms that effectively take advantage of inter-channel correlation. An audio decoder performs corresponding processing and decoding. In addition, the decoder performs a post-processing multi-channel transform for any of multiple different purposes.

Claims

1. In an audio encoder, a computer-implemented method comprising:

receiving a frame of multi-channel audio data;

grouping plural windows from different channels in the frame into one or more tiles, wherein each tile of the one or more tiles groups one or more co-located windows among the plural windows from the different channels in the frame, wherein plural channels of the different channels have different window configurations in the frame, and wherein at least one tile of the one or more tiles groups co-located windows from the plural channels having different window configurations in the frame; and

outputting tile configuration information for the one or more tiles, the tile configuration information indicating how the plural windows are grouped into the one or more tiles.

2. The method of claim 1 wherein the multi-channel audio data is in two channels.

3. The method of claim 1 wherein the multi-channel audio data is in more than two channels.

4. The method of claim 1 wherein, for each tile of the one or more tiles, the group of one or more co-located windows for the tile shares a start position for the tile and shares an end position for the tile.

5. The method of claim 4 wherein the different channels include first, second, and third channels with different window configurations in the frame, wherein the first channel includes a first window and a second window, wherein the second channel includes a window co-located in position with the first window of the first channel, wherein the third channel includes a window co-located in position with the second window of the first channel, wherein the first window of the first channel is in a first tile along with the window of the second channel, and wherein the second window of the first channel is in a second tile along with the window of the third channel.

6. The method of claim 1 wherein the tile configuration information includes tile size and channel member information.

7. The method of claim 1 wherein the outputting comprises sending a signal to indicate whether the different channels all have an identical window configuration.

8. The method of claim 7 wherein the outputting further comprises, if the different channels do not all have an identical window configuration, sending one or more channel masks and sending one or more tile sizes.

9. A storage medium storing computer-executable instructions for causing a computer programmed thereby to perform the method of claim 1.

10. In an audio encoder, a computer-implemented method comprising:

receiving audio data in plural channels, wherein the plural channels include first, second, and third channels;

partitioning the audio data into plural windows, wherein the encoder independently partitions the audio data in each of the plural channels;

grouping the plural windows into plural groups, wherein the plural groups include first and second groups, wherein windows in the first and second channels but not the third channel are members of the first group, wherein windows in the first and third channels but not the second channel are members of the second group, and wherein the encoder groups windows that are in different channels but have the same start time and same stop time into a single one of the plural groups; and

outputting configuration information for the plural groups.

11. The method of claim 10 wherein a third group of the plural groups includes windows from three or more channels.

12. A storage medium storing computer-executable instructions for causing a computer programmed thereby to perform the method of claim 10.

13. In an audio decoder, a computer-implemented method comprising:

receiving encoded audio data in plural channels in a frame;

retrieving tile configuration information for one or more tiles, the tile configuration information indicating how plural windows from the plural channels are grouped into the one or more tiles, wherein each of the one or more tiles groups one or more co-located windows among the plural windows from the plural channels in the frame, wherein at least some of the plural channels have different window configurations in the frame, and wherein at least one tile of the one or more tiles groups co-located windows from the at least some channels having different window configurations in the frame; and

decoding the audio data based at least in part upon the retrieved tile configuration information.

14. The method of claim 13 wherein the plural channels consist of two channels.

15. The method of claim 13 wherein the plural channels consist of more than two channels.

16. The method of claim 13 wherein, for each tile of the one or more tiles, the group of one or more co-located windows for the tile shares a start position for the tile and shares an end position for the tile.

17. The method of claim 13 wherein the tile configuration information includes tile size and channel member information.

18. The method of claim 13 wherein the retrieving comprises getting a signal to indicate whether the plural channels all have an identical window configuration.

19. The method of claim 18 wherein the retrieving further comprises, if the plural channels do not all have an identical window configuration, getting one or more channel masks and getting one or more tile sizes.

20. A storage medium storing computer-executable instructions for causing a computer programmed thereby to perform the method of claim 13.

21. The method of claim 16 wherein the plural channels include first, second, and third channels with different window configurations in the frame, wherein the first channel includes a first window and a second window, wherein the second channel includes a window co-located in position with the first window of the first channel, wherein the third channel includes a window co-located in position with the second window of the first channel, wherein the first window of the first channel is in a first tile along with the window of the second channel, and wherein the second window of the first channel is in a second tile along with the window of the third channel.

22. In an audio decoder, a computer-implemented method comprising:

receiving encoded audio data in plural channels, wherein the plural channels include first, second, and third channels;

retrieving configuration information for plural groups, the audio data in the plural channels having been partitioned into plural windows, wherein the configuration information indicates how the plural windows from the plural channels are grouped into the plural groups, wherein the plural groups include first and second groups, wherein windows in the first and second channels but not the third channel are members of the first group, wherein windows in the first and third channels but not the second channel are members of the second group, and wherein the configuration information defines the plural groups such that windows that are in different channels but have the same start time and same stop time are grouped into a single one of the plural groups; and

decoding the audio data based at least in part upon the retrieved configuration information.

23. The method of claim 22 wherein a third group of the plural groups includes windows from three or more channels.

24. A storage medium storing computer-executable instructions for causing a computer programmed thereby to perform the method of claim 22.