# US 10,121,480 B2 · Method and apparatus for encoding audio data

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- Number: US 10,121,480 B2
- Document ID: US10121480B2
- Status: Granted
- Kind: B2
- Application number: 15/222,283
- Filed: 2016-07-28
- Published: 2017-01-26
- Granted: 2018-11-06
- Earliest claimed: 2010-11-25
- Assignees: Intel Corporation
- Applicants: Intel Corporation
- Inventors: Dmitry N. Budnikov; Igor Igor Chikalov; Sergey N. Zheltov
- Web page: https://patentgrep.com/patent/US10121480B2

## CPC

- G10L 19/035: Scalar quantisation
- G10L 19/012: Comfort noise or silence coding
- G10L 19/0204: {using subband decomposition}
- G10L 21/04: Time compression or expansion
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING

## Abstract

A method for processing audio data includes determining a first common scalefactor value for representing quantized audio data in a frame. A second common scalefactor value is determined for representing the quantized audio data in the frame. A line equation common scalefactor value is determined from the first and second common scalefactor values.

## Claims

### Claim 1

An audio encoder circuit, comprising:
a scaler/quantizer unit to determine a first common scalefactor value for representing quantized audio data in a frame, a second common scalefactor value for representing the quantized audio data in the frame, and a line equation common scalefactor value; and
a noiseless coding unit to receive the line equation common scalefactor.

### Claim 2 (depends on 1)

The audio encoder of claim 1, wherein the first common scalefactor value requires a first number of bits that exceeds a predetermined threshold number, and the second common scalefactor value requires a second number of bits that does not exceed the predetermined threshold number.

### Claim 3 (depends on 2)

The audio encoder of claim 2, wherein the predetermined threshold number is a number of available bits to conform with a predetermined bit rate.

### Claim 4 (depends on 1)

The audio encoder of claim 1, wherein one of the first common scalefactor value and the second common scalefactor value is a common scalefactor value from a previous frame.

### Claim 5 (depends on 1)

The audio encoder of claim 1, wherein the scaler/quantizer unit determines the line equation common scalefactor value from the first and second common scalefactor values.

### Claim 6 (depends on 1)

The audio encoder circuit of claim 1, wherein the first common scalefactor value represents a high point where a number of bits required to represent the quantized audio data with the first common scalefactor value exceeds a number of available bits, and the second common scalefactor value represents a low point where a number of bits required to represent the quantized audio data with the second common scalefactor value does not exceed the number of available bits.

### Claim 7 (depends on 1)

The audio encoder circuit of claim 1, wherein the noiseless coding unit determines a number of bits required for representing audio data in the frame quantized using the line equation common scalefactor value and a number of bits required for representing the line equation common scalefactor value.

### Claim 8 (depends on 7)

The audio encoder circuit of claim 7 further comprising an iterative control unit to direct modification of the line equation common scalefactor value and re-quantization of the audio data in the frame with a modified line equation common scalefactor value if the number of bits required exceeds an available number of bits.

### Claim 9 (depends on 1)

The audio encoder circuit of claim 1, wherein the scaler/quantizer unit designates the line equation common scalefactor value as the common scalefactor value for representing the audio data in the frame.

### Claim 10 (depends on 8)

The audio encoder circuit of claim 8, wherein the iterative control unit determines distortion for each spectral band in the audio data of the frame; and
directs modification of an individual scalefactor value corresponding to a spectral band if distortion for the spectral band exceeds allowed distortion.

### Claim 11

A method for processing audio data, comprising:
determining a first common scalefactor value for representing quantized audio data in a frame;
determining a second common scalefactor value for representing the quantized audio data in the frame, wherein at least one of the determinings is performed by a processor;
identifying a line equation common scalefactor value and designating the line equation common scalefactor value as a common scalefactor value for representing the quantized audio data in the frame, wherein at least one of the determinings and identifying is performed by a processor.

### Claim 12 (depends on 11)

The method of claim 11, wherein determining the first common scalefactor value for representing quantized audio data in the frame comprises selecting a common scalefactor value from a previous frame.

### Claim 13 (depends on 11)

The method of claim 11, wherein the first common scalefactor value requires a number of bits that exceeds a predetermined threshold number, and the second common scalefactor value requires a number of bits that does not exceed the predetermined threshold number.

### Claim 14 (depends on 13)

The method of claim 13, wherein the predetermined threshold number is a number of available bits to conform with a predetermined bit rate.

### Claim 15 (depends on 11)

The method of claim 11 wherein the line equation common scalefactor value is determined from the first and second common scalefactor values.

### Claim 16 (depends on 11)

The method of claim 11, wherein the first common scalefactor value represents a high point where a number of bits required to represent the quantized audio data with the first common scalefactor value exceeds a number of available bits, and the second common scalefactor value represents a low point where a number of bits required to represent the quantized audio data with the second common scalefactor value does not exceed the number of available bits.

### Claim 17 (depends on 15)

The method of claim 15 further comprising:
quantizing the audio data in the frame with the line equation common scalefactor value;
determining a number of bits required for representing the quantized audio data in the frame and the line equation common scalefactor value; and
modifying the line equation common scalefactor value and re-quantizing the audio data in the frame with a modified line equation common scalefactor value if a number of bits required exceeds an available number of bits.

### Claim 18 (depends on 11)

The method of claim 11, further comprising:
determining distortion for each spectral band in the audio data of the frame; and
modifying an individual scalefactor value corresponding to a spectral band if distortion for the spectral band exceeds allowed distortion.

### Claim 19

A method for processing audio data, comprising:
determining a first common scalefactor value for representing quantized audio data in a first frame and determining a second common scalefactor value for representing quantized audio data in a second frame; and
quantizing modified discrete cosine transform (MDCT) coefficients with a common scalefactor value having a value of the first common scalefactor value determined for the first frame, wherein at least one of the determining and quantizing is performed by a processor.

### Claim 20 (depends on 19)

The method of claim 19 further comprising:
determining a number of bits required for representing the quantized MDCT coefficients and the common scalefactor value; and
modifying the common scalefactor value and re-quantizing the MDCT coefficients with the modified common scalefactor if the number of bits required exceeds an available number of bits, wherein at least one of the determinings, quantizing, and modifying procedures is performed by a processor.

### Claim 21 (depends on 20)

The method of claim 20 further comprising modifying the common scalefactor value and re-quantizing the MDCT coefficients until the number of bits required is less than or equal to the available number of bits.

### Claim 22 (depends on 20)

The method of claim 20, wherein modifying the common scalefactor value comprises adding a quantizer incrementation value to the common scalefactor value.

### Claim 23 (depends on 20)

The method of claim 20, wherein the first common scalefactor value represents a high point where a number of bits required to represent the quantized audio data with the first common scalefactor value exceeds a number of available bits, and the second common scalefactor value represents a low point where a number of bits required to represent the quantized audio data with the second common scalefactor value does not exceed the number of available bits.

### Claim 24 (depends on 19)

The method of claim 19, wherein determining the first common scalefactor value for representing the quantized audio data in the first frame comprises determining a common scalefactor value for representing quantized audio data in a previous frame.