Patent ID: 9514755
Filing Date: 2016-12-06
CPC Classification: G10L

Claim Text:
1. A method for concealing one or more consecutive lost packets; wherein a lost packet is a packet which is deemed to be lost by a transform-based audio decoder; wherein the transform-based audio decoder applies an overlapped transform; wherein each of the one or more lost packets comprises a set of transform coefficients; wherein each set of transform coefficients comprises N transform coefficients, with N>1; wherein for each set of transform coefficients, the overlapped transform generates a corresponding aliased intermediate frame of 2N samples; wherein for each received packet, wherein the overlapped transform generates the corresponding frame of the audio signal, based on a first half of the corresponding aliased intermediate frame and based on a second half of the aliased intermediate frame of a packet which precedes the received packet; and wherein a set of transform coefficients is used by the transform-based audio decoder to generate a corresponding frame of a time domain audio signal; the method comprising: determining a last received packet comprising a last received set of transform coefficients; wherein the last received packet is directly preceding the one or more lost packets; determining contents of a first buffer based on a last received frame of the audio signal; wherein the last received frame corresponds to the last received packet; determining contents of a second buffer based on the second half of the aliased intermediate frame of the last received packet; determining for a current lost packet of the one or more lost packets a number of preceding lost packets from the one or more lost packets; wherein the determined number is referred to as a loss position; determining a packet loss concealment, referred to as PLC, scheme based on the loss position of the current packet; and determining an estimate of a current frame of the audio signal using the determined PLC scheme; wherein the current frame corresponds to the current lost packet.