# US 2014/0156287 A1 · Bitstream syntax for multi-process audio decoding

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- Number: US 2014/0156287 A1
- Document ID: US20140156287A1
- Status: Published application
- Kind: A1
- Application number: 14/172,807
- Filed: 2014-02-04
- Published: 2014-06-05
- Earliest claimed: 2007-06-29
- Assignees: Microsoft Corporation
- Applicants: Microsoft Corporation
- Inventors: Kazuhito Koishida; Sanjeev Mehrotra; Chao He; Wei-Ge Chen
- Web page: https://patentgrep.com/patent/US20140156287A1

## CPC

- G10L 19/167: {Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes}
- G10L 19/002: Dynamic bit allocation (for perceptual audio coders G10L19/032)
- G10L 19/008: Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
- G10L 19/022: Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring
- G10L 19/03: Spectral prediction for preventing pre-echo; Temporary noise shaping [TNS], e.g. in MPEG2 or MPEG4
- G10L 19/038: Vector quantisation, e.g. TwinVQ audio
- G10L 19/04: using predictive techniques
- G10L 19/24: Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING

## Abstract

An audio decoder provides a combination of decoding components including components implementing base band decoding, spectral peak decoding, frequency extension decoding and channel extension decoding techniques. The audio decoder decodes a compressed bitstream structured by a bitstream syntax scheme to permit the various decoding components to extract the appropriate parameters for their respective decoding technique.

## Claims

### Claim 1

A method of decoding a compressed audio bitstream containing syntax elements conforming to a bitstream syntax, the bitstream syntax defining a base coding layer and a frequency extension coding layer for coding a portion of audio content using a frequency extension coding, the method comprising:
reading the base coding layer and frequency extension coding layer of the compressed audio bitstream;
parsing a plurality of syntax elements from the frequency extension coding layer specifying parameters used in the frequency extension coding, wherein the parameters comprise parameters specifying frequency extension coding using a different transform window size than a base coding layer;
processing coded audio content of the frequency extension coding layer to reconstruct the portion of audio content in an output audio signal;
playing the output audio signal.

### Claim 2 (depends on 1)

The method of claim 1 wherein the parameters comprise parameters identifying tiles coded using frequency extension coding with a different transform window size than a based coding layer.

### Claim 3 (depends on 1)

The method of claim 1 wherein the parameters comprise dynamic band configuration parameters specifying spectral band locations where frequency extension coding is applied.

### Claim 4 (depends on 1)

The method of claim 1 wherein said dynamic band configuration parameters specify start and end positions of spectral bands coded using vector quantization techniques.

### Claim 5 (depends on 1)

The method of claim 1 wherein the parameters comprise displacement vector search range, step size for displacement vector quantization, scale factor and codeword modifications.