# US 10,319,386 B2 · Methods and apparatuses for DTX hangover in audio coding

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- Number: US 10,319,386 B2
- Document ID: US10319386B2
- Status: Granted
- Kind: B2
- Application number: 14/769,603
- Filed: 2013-12-12
- Published: 2016-01-07
- Granted: 2019-06-11
- Earliest claimed: 2013-02-22
- Assignees: Telefonaktiebolaget LM Ericsson (publ)
- Applicants: Telefonaktiebolaget L M Ericsson (publ)
- Inventors: Stefan Bruhn; Tomas Jansson Toftgård; Martin Sehlstedt
- Web page: https://patentgrep.com/patent/US10319386B2

## CPC

- G10L 19/012: Comfort noise or silence coding
- G10L 19/005: Correction of errors induced by the transmission channel, if related to the coding algorithm
- G10L 19/02: using spectral analysis, e.g. transform vocoders or subband vocoders
- G10L 19/173: {Transcoding, i.e. converting between two coded representations avoiding cascaded coding-decoding}
- G10L 25/51: for comparison or discrimination
- G10L 25/69: for evaluating synthetic or decoded voice signals
- G10L 25/84: for discriminating voice from noise
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING

## Abstract

Transmitting node and receiving node for audio coding and methods therein. The nodes being operable to encode/decode speech and to apply a discontinuous transmission (DTX) scheme comprising transmission/reception of Silence Insertion Descriptor (SID) frames during speech inactivity. The method in the transmitting node comprising determining, from amongst a number N of hangover frames, a set Y of frames being representative of background noise, and further transmitting the N hangover frames, comprising at least said set Y of frames, to the receiving node. The method further comprises transmitting a first SID frame to the receiving node in association with the transmission of the N hangover frames, where the SID frame comprises information indicating the determined set Y of hangover frames to the receiving node. The method enables the receiving node to generate comfort noise based on the hangover frames most adequate for the purpose.

## Claims

### Claim 1

A method performed by transmitting node, the node being operable to encode speech and to apply a discontinuous transmission (DTX) scheme comprising transmission of Silence Insertion Descriptor (SID) frames during speech inactivity, the method comprising:
determining a number N of hangover frames, wherein the number N of hangover frames is variable;
transmitting the N hangover frames to a receiving node comprising a decoder; and enabling the decoder to generate comfort noise based on the N hangover frames, wherein the enabling step comprises transmitting a first SID frame to the receiving node in association with the transmission of the N hangover frames,
wherein the SID frame comprises a counter value indicating the determined number N of hangover frames, and
determining the number N of hangover frames comprises determining the number of frames generated during a period in which an activity detection flag is set to a certain value and a second flag is set to a certain value.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first SID frame further comprises SID parameters.

### Claim 3 (depends on 1)

The method of claim 1, wherein the number N of hangover frames is dynamically variable based on properties of an input audio signal.

### Claim 4

A transmitting node, operable to encode speech and to apply a discontinuous transmission (DTX) scheme comprising transmission of Silence Insertion Descriptor (SID) frames during speech inactivity, the transmitting node comprising a transmitter and a data processing system, the data processing system being operative to:
determine a number N of hangover frames, wherein the number N of hangover frames is variable;
employ the transmitter to transmit the N hangover frames to a receiving node comprising a decoder; and
employ the transmitter to transmit a first SID frame to the receiving node in association with the transmission of the N hangover frames, wherein
the SID frame comprises a counter value indicating the determined number N of hangover frames, thereby enabling the decoder to generate comfort noise based on the N hangover frames, and
the transmitting node is configured to determine the number N of hangover frames by performing a process comprising determining the number of frames generated during a period in which an activity detection flag is set to a certain value and a second flag is set to a certain value.

### Claim 5 (depends on 4)

The transmitting node of claim 4, wherein the data processing system comprise a processor and a memory and wherein said memory is containing instructions executable by said processor.

### Claim 6 (depends on 4)

The transmitting node of claim 4, wherein the first SID frame further comprises SID parameters.

### Claim 7 (depends on 4)

The transmitting node of claim 4, wherein the number N of hangover frames is dynamically variable based on properties of an input audio signal.

### Claim 8

A transmitting node, operable to encode speech and to apply a discontinuous transmission (DTX) scheme comprising transmission of Silence Insertion Descriptor (SID) frames during speech inactivity, the transmitting node comprising:
a transmitter; and
a data processing system, the data processing system being configured to:
determine a number N of hangover frames, wherein the number N of hangover frames is variable;
employ the transmitter to transmit the N hangover frames to a receiving node comprising a decoder; and
employ the transmitter to transmit a first SID frame to the receiving node in association with the transmission of the N hangover frames, wherein
the SID frame comprises a counter value indicating the determined number N of hangover frames, thereby enabling the decoder to generate comfort noise based on the N hangover frames, and
the data processing system is configured to determine the number N of hangover frames by performing a process comprising determining the number of frames generated during a period in which an activity detection flag is set to a certain value and a second flag is set to a certain value.

### Claim 9 (depends on 1)

A computer program product comprising a non-transitory computer readable medium storing computer program code, which when run in a transmitting node causes the transmitting node to perform the method of claim 1.