Generation of comfort noise
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorTomas Jansson Toftgård
Life of this patent
Estimating the term…
Abstract
A comfort noise controller for generating CN (Comfort Noise) control parameters is described. A buffer of a predetermined size is configured to store CN parameters for SID (Silence Insertion Descriptor) frames and active hangover frames. A subset selector is configured to determine a CN parameter subset relevant for SID frames based on the age of the stored CN parameters and on residual energies. A comfort noise control parameter extractor (50B) is configured to use the determined CN parameter subset to determine the CN control parameters for a first SID frame following an active signal frame.
Claims16
A method of generating Comfort Noise (CN) control parameters, comprising:
- storing CN parameter sets in a buffer of a predetermined size (M) for Silence Insertion Descriptor (SID) frames and active hangover frames of an encoded audio signal, where the CN parameter set stored for each SID frame or active hangover frame includes a residual energy value;
- determining representative CN parameters for a first SID frame following an active non-hangover frame of the encoded audio signal, based on a relevant subset of the CN parameter sets stored in the buffer, and determining the relevant subset based on an age of the stored CN parameter sets and the residual energy values;
- and
- using the representative CN parameters to determine the CN control parameters for the first SID frame.
A non-transitory computer readable medium storing a computer program for generating Comfort Noise (CN) control parameters, said computer program comprising computer readable code units that when executed by a processing circuit of a computer configures the processing circuit to:
- store CN parameter sets in a buffer of a predetermined size (M) for Silence Insertion Descriptor (SID) frames and active hangover frames of an encoded audio signal, wherein the CN parameter set stored for each SID frame or active hangover frame includes a residual energy value;
- determine representative CN parameters for a first SID frame following an active non-hangover frame of the encoded audio signal, based on a relevant subset of the CN parameter sets stored in the buffer, and determining the relevant subset based on an age of the stored CN parameter sets and the residual energy values;
- use the representative CN parameters to determine the CN control parameters for the first SID frame.
A comfort noise controller for generating Comfort Noise (CN) control parameters, comprising:
- a buffer of a predetermined size (M) configured to store CN parameter sets for Silence Insertion Descriptor (SID) frames and active hangover frames of an encoded audio signal, where the CN parameter set stored for each SID frame or active hangover frame includes a residual energy value;
- and
- processing circuitry configured to:
- determine representative CN parameters for a first SID frame following an active non-hangover frame of the encoded audio signal, based on a relevant subset of the CN parameter sets stored in the buffer, and determine the relevant subset based on an age of the stored CN parameter subsets and the residual energy values;
- and
- use the representative CN parameters determine the CN control parameters for the first SID frame.
An audio decoder comprising:
- a buffer circuit;
- and
- processing circuitry configured to:
- store, as a buffer entry in the buffer circuit, comfort-noise parameter values received for Silence Insertion Descriptor (SID) frames and active hangover frame of an encoded audio signal, the comfort-noise parameters including at least a residual energy value for the corresponding SID or active hangover frame;
- for a first SID frame following one or more active non-hangover frames of the encoded audio signal:
- select one or more first buffer entries, in order of recency and in dependence on how many active non-hangover frames preceded the first SID frame;
- select one or more second buffer entries from the one or more first buffer entries, as those first buffer entries having residual energy values that fall within a defined range of the residual energy value of the most recent buffer entry;
- and
- generate comfort noise values for the first SID frame, in dependence on the one or more second buffer entries.
Dependencies are inferred from the claim text.