Encoding of multiple audio signals

Patent metadata

Field	Value
Publication number	US-10115403-B2
Application number	US-201615372980-A
Country	US
Kind code	B2
Filing date	Dec 8, 2016
Priority date	Dec 18, 2015
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A device includes a processor, a memory, and a combiner. The processor is configured to receive a first combined frame and a second combined frame corresponding to a multi-channel audio signal. The memory is configured to store first lookahead portion data of the first combined frame. The first lookahead portion data is received from the processor. The combiner is configured to generate a frame at a multi-channel encoder. The frame includes a subset of samples of the first lookahead portion data, one or more samples of updated sample data corresponding to the first combined frame, and a group of samples of second combined frame data corresponding to the second combined frame.

First claim

What is claimed is:

1. A device comprising:
a processor configured to receive a first combined frame and a second combined frame corresponding to a multi-channel audio signal;
a memory configured to store first lookahead portion data of the first combined frame, the first lookahead portion data received from the processor; and
a combiner configured to generate a frame at a multi-channel encoder, the frame including a subset of samples of the first lookahead portion data, one or more samples of updated sample data corresponding to the first combined frame, and a group of samples of second combined frame data corresponding to the second combined frame.

2. The device of claim 1 , wherein the first combined frame includes a combination of a first input frame of a first audio channel of the multi-channel audio signal and a second input frame of a second audio channel of the multi-channel audio signal.

3. The device of claim 2 , further comprising:
a sample corrector configured to generate at least a particular portion of a second version of the first combined frame based on the first input frame, the second input frame, and a second particular input frame of the second audio channel,
wherein the second combined frame includes a particular combination of a first particular input frame of the first audio channel and the second particular input frame, and
wherein the processor is further configured to generate the updated sample data by processing at least the particular portion of the second version of the first combined frame.

4. The device of claim 1 , wherein the subset of samples of the first lookahead portion data excludes sample information from a second audio channel of the multi-channel audio signal.

5. The device of claim 4 , wherein the one or more samples of the updated sample data include the sample information.

6. The device of claim 1 , wherein the subset of samples of the first lookahead portion data includes predicted sample information corresponding to a second audio channel of the multi-channel audio signal.

7. The device of claim 1 , wherein the processor is further configured to generate the second combined frame data by processing a frame portion of the second combined frame.

8. The device of claim 1 , wherein the processor includes at least one of a high-pass filter, a resampler, or an emphasis adjuster.

9. The device of claim 1 , wherein the processor includes:
a high-pass filter configured to generate a filtered signal by filtering an input signal; and
a resampler configured to generate a resampled signal by resampling the filtered signal,
wherein the processor is configured to generate a pre-processed signal based on the resampled signal.

10. The device of claim 9 , wherein the resampler includes a downsampler configured to generate the resampled signal by downsampling the filtered signal.

11. The device of claim 9 , wherein the processor further includes an emphasis adjuster configured to generate an emphasized signal by adjusting an emphasis of the resampled signal, wherein the pre-processed signal is based on the emphasized signal.

12. The device of claim 9 , wherein the input signal includes a first lookahead portion of the first combined frame, at least a particular portion of a second version of the first combined frame, or a frame portion of the second combined frame.

13. The device of claim 9 , wherein the pre-processed signal includes the first lookahead portion data, the updated sample data, or the second combined frame data.

14. The device of claim 1 , wherein the processor is configured to:
generate the subset of samples of the first lookahead portion data using a filter;
determine a first filter state of the filter upon generation of the subset of samples of the first lookahead portion data;
store the first filter state in the memory;
subsequent to generating the subset of samples of the first lookahead portion data, generate a second subset of samples of the first lookahead portion data using the filter, wherein the filter has a second filter state upon generation of the second subset of samples of the first lookahead portion data;
reset the filter to have the first filter state; and
generate the updated sample data using the filter having the first filter state.

15. The device of claim 1 , further comprising:
a first microphone configured to receive a first audio channel;
a second microphone configured to receive a second audio channel, the first audio channel corresponding to a leading audio channel of the first audio channel and the second audio channel, and the second audio channel corresponding to a lagging audio channel of the first audio channel and the second audio channel; and
a temporal equalizer configured to:
determine a value indicative of an amount of temporal mismatch between the first audio channel and the second audio channel; and
generate the multi-channel audio signal based on first samples of the first audio channel and second samples of the second audio channel, the second samples shifted relative to the first samples based on the value.

16. The device of claim 1 , wherein the updated sample data is based on one or more downmixing parameter values that are used to generate the first combined frame.

17. The device of claim 1 , further comprising:
a first microphone configured to receive a first audio channel; and
a second microphone configured to receive a second audio channel, the first audio channel corresponding to a leading audio channel of the first audio channel and the second audio channel, and the second audio channel corresponding to a lagging audio channel of the first audio channel and the second audio channel, wherein the multi-channel audio signal is based on the first audio channel and the second audio channel.

18. The device of claim 1 , the combiner further configured to generate a second frame at the multi-channel encoder, the second frame including a group of samples of first combined frame data corresponding to the first combined frame, the second frame corresponding to a first output frame, wherein the first output frame has a shorter duration than first combined frame.

19. The device of claim 18 , wherein the first output frame corresponds to an initial frame, and wherein the frame corresponds to a second output frame, the second output frame corresponding to a period of time after the first output frame.

20. The device of claim 18 , wherein the group of samples of the first combined frame data corresponding to the first combined frame comprises a portion of a pre-processed first combined frame.

21. A method of encoding comprising:
storing, at a device, first lookahead portion data of a first combined frame, the first combined frame and a second combined frame corresponding to a multi-channel audio signal; and
generating, by a combiner of the device, a frame at a multi-channel encoder of the device, the frame including a subset of samples of the first lookahead portion data, one or more samples of updated sample data corresponding to the first combined frame, and a group of samples of second combined frame data corresponding to the second combined frame.

22. The method of claim 21 , wherein the first combined frame includes a combination of a first input frame of a first audio channel of the multi-channel audio signal and a second input frame of a second audio channel of the multi-channel audio signal, wherein the subset of samples of the first lookahead portion data excludes

Assignees

• Qualcomm Inc

Inventors

• Atti Venkatraman
• Chebiyyam Venkata Subrahmanyam Chandra Sekhar

Classifications

• G10L19/008 Primary

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title

• H04S2400/15

  Aspects of sound capture and related signal processing for recording or reproduction · CPC title

• H04S2400/03

  Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 (H04S2400/01 takes precedence) · CPC title

• G10L19/022

  Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring · CPC title

• G10L19/26

  Pre-filtering or post-filtering · CPC title